Biodegradable implant precursor
Abstract
THE INVENTION IS RELATED TO A BIODEGRADABLE GRAFT PRECURSOR, WHICH HAS A TWO-PART STRUCTURE MADE OF AN EXTERNAL BAG AND A LIQUID CONTENT. THE GRAFT PRECURSOR IS FORMED BY A THERMOPLASTIC POLYMER COAGULABLE IN WATER AND BIODEGRADABLE, AND AN ORGANIC MISCIBLE SOLVENT IN WATER. WHEN ADMINISTERING A PLACE OF GRAFTING IN AN ANIMAL, THE PRECURSOR OF THE GRAFTING WILL SOLIDIFY IN SITU TO A MICROPOROUS, SOLID MATRIX THROUGH THE DISSIPATION OF THE ORGANIC SOLVENT TO SURROUND TISSUE FLUIDS AND COAGULATION OF THE POLYMER. THE INVENTION ALSO INCLUDES METHODS FOR MAKING THE GRAFT PRECURSOR, AN APPARATUS FOR FORMING THE PRECURSOR, AND A KIT CONTAINING THE APPARATUS. METHODS OF USE OF THE GRAFT PRECURSOR ARE ALSO PROVIDED TO TREAT A TISSUE DEFECT IN AN ANIMAL, FOR EXAMPLE, TO REINFORCE CELL DEVELOPMENT AND REGENERATION OF TISSUE, HEALING OF WOUNDS AND DENOS, REGENERATION OF NERVIOS, REGENERATION AND SIMILAR, FOR DELIVERY OF BIOLOGICALLY ACTIVE SUBSTANCES TO TISSUES OR ORGANS, AND OTHER THERAPIES.

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32 claims: 5 independent, 27 dependent
- 1ES 2 173 102 T3 REIVINDICACIONES 1. Un precursor de implante para la implantación en un tejido defectuoso en un animal, incluyendo:una estructura en dos partes compuesta de una bolsa exterior y un contenido líquido;incluyendo el precursor de implante una mezcla de un polímero termoplastico biocompatible, biodegradable, coagulable en agua, y un solvente orgónico farmacóeuticamente aceptable, soluble en agua.
- 2El precursor de implante seguón la reivindicacióon 1, donde el contenido lóquido del precursor de implante tiene una consistencia del orden de acuosa a viscosa, y la bolsa exterior tiene una consistencia del orden de gelatinosa a parecida a cera.
- 3El precursor de implante seguón la reivindicacióon 1 oó 2, donde el precursor de implante es capaz de volver a una forma completamente líquida despuós de aproximadamente 30-90 minutos de formarse, y sin contacto siguiente con un medio acuoso.
- 4El precursor de implante segun cualquiera de las reivindicaciones 1 a 3, donde el polómero termoplaóstico se selecciona del grupo que consta de polilaóctidos, poliglicóolidos, policaprolactonas, polianhídridos, poliamidas, poliuretanos, poliesteramidas, poliortoóesteres, polidioxanonas, poliacetales, policetales, policarbonatos, poliortocarbonatos, polifosfacenos, polihidroxibutiratos, polihidroxivaleratos, oxalatos de polialquileno, succinatos de polialquileno, íacido polimaílico, poliamino íacidos, polimetil vinil íeter, quitina, quitosían, y copolímeros, terpolímeros, y cualquier combinaciíon de los mismos.
- 5El precursor de implante segón la reivindicacioín 1, donde el solvente se selecciona del grupo que consta de N-metil-2-pirrolidona, 2-pirrolidona, etanol, propilen glicol, carbonato de propileno, acetona, aícido acíetico, acetato de etilo, lactato de etilo, acetato de metilo, metil etil cetona, dimetilformamida, dimetilsultoíxido, dimetil sulfona, tetrahidrofurano, caprolactama, decilmetilsulfíoxido, íacido oleico, N,N-dietil-m-toluamida, y 1-dodecilazacicloheptan-2-ona, y cualquier combinaciíon de los mismos.
- 6El precursor de implante segón la reivindicaciíon 1, incluyendo ademías un agente formador de poros seleccionado del grupo que consta esencialmente de un azucar, una sal, un polímero soluble en agua, y una sustancia insoluble en agua que se degrada raípidamente a una sustancia soluble en agua.
- 7El precursor de implante seguín la reivindicaciíon 1, incluyendo ademías un agente biolíogicamente activo seleccionado del grupo que consta de un agente antibacteriano, un agente antifungoso, y un agente antivírico.
- 8El precursor de implante segón la reivindicaciíon 1, incluyendo ademaís un agente bioloógicamente activo seleccionado del grupo que consta de un agente antiinflamatorio, un agente antiparasótico, agente antineoplóasico, un agente analgóesico, un agente anestóesico, una vacuna, un agente del sistema nervioso central, un factor de crecimiento, una hormona, una antihistamina, un agente osteoinductivo, un agente cardiovascular, un agente antiulceroso, un agente broncodilatador, un agente vasodilatador, un agente de control de natalidad, y un agente mejorador de fertilidad.
- 9El precursor de implante seguón la reivindicacióon 1, incluyendo ademaós una sustancia promotora del crecimiento óoseo.
- 10El precursor de implante seguón la reivindicacióon 9, donde la sustancia promotora del hueso es proteóna morfogóenica del hueso.
- 11El precursor de implante de la reivindicacióon 9, donde la sustancia promotora del crecimiento óoseo es hidroxiapatita.
- 12El precursor de implante seguón la reivindicacióon 1, incluyendo ademóas un agente de modificación de velocidad de liberación para controlar la velocidad de liberacioón de un agente bioloógico in vivo de la matriz de implante.
- 13El precursor de implante seguón la reivindicacióon 12, donde el agente de modificacioón de velocidad de liberacioón se selecciona del grupo que consta de un óester de un óacido monocarboxólico, un óester de un óacido dicarboxólico, un óester de un aócido tricarboxólico, un polihidroxi alcohol, un aócido graso, un trióester de glicerol, un esterol, un alcohol, y cualquier combinacioón de los mismos.
- 14El precursor de implante seguón la reivindicacióon 13, donde el agente de modificacióon de velocidad de liberacioón se selecciona del grupo que consta de acetato de 2-etoxietilo, acetato de metilo, acetato de etilo, ftalato de dietilo, ftalato de dimetilo, ftalato de dibutilo, adipato de dimetilo, succinato de dimetilo, oxalato de dimetilo, citrato de dimetilo, citrato de trietilo, citrato acetil tributólico, citrato acetil trietólico, triacetato de glicerol, sebecato de di(n-butilo), propilen glicol, polietilen glicol, glicerina, sorbitol, triglicóerido, aceite de soja epoxidizado, colesterol, un alcanol de C 6 -C 12 , 2-etoxietanol, o cualquier combinacion de los mismos.
- 15El precursor de implante seguón la reivindicacióon 13, donde el agente de modificacioón de velocidad de liberacioón se selecciona del grupo que consta de citrato de dimetilo, citrato de trietilo, heptanoato de etilo, glicerina, hexanodiol, y cualquier combinacióon de los mismos.
- 16Un móetodo de hacer un precursor de implante ex vivo, incluyendo:(a) aplicar una cantidad eficaz de un medio acuoso a una superficie de un sustrato soólido de soporte para formar una capa acuosa;(b) dispensar una cantidad eficaz de una solucióon polimóerica lóquida sobre la capa acuosa;incluyendo la solucioón polimóerica un polómero termoplaóstico biodegradable, biocompatible, coagulable en agua y un solvente orgaónico farmacóeuticamente aceptable, miscible en agua;(c) aplicar una cantidad eficaz de un medio acuoso sobre la superficie de la solucióon polimóerica;y (d) dejar que el polómero adyacente al medio acuoso coagule para formar el precursor de implante incluyendo una estructura en dos partes compuesta de una bolsa exterior y un contenido lóquido;31 ES 2 siendo efectiva la cantidad de medio acuoso aplicado en pasos (a) y (c) para producir coagulación superficial del polímero para formar la bolsa exterior del precursor de implante.
- 17El metodo segun la reivindicación 16, incluyendo ademós el paso (e) de mantener el precursor de implante a un espesor de aproximadamente 400-1500 pm.
- 18El metodo segun la reivindicacion 16 o 17, donde el espesor del precursor de implante se mantiene comprimiendo la solucióon polimóerica coagulante durante el paso (d).
- 19El metodo segun cualquiera de las reivindicaciones 16 a 18, donde el sustrato de soporte incluye vidrio, plóastico poroso, acero inoxidable sinterizado, porcelana, material óseo, hueso, espuma de celulosa oxidada, espuma polimóerica biocompatible, partóculas de polómero biocompatible, fosfato tricaólcico y materiales sanguóneos.
- 20El móetodo seguón cualquiera de las reivindicaciones 16 a 19, incluyendo ademóas antes del paso (a), los pasos de:(i) aplicar una cantidad pequena, pero eficaz, de un medio acuoso como una capa en la superficie del sustrato de soporte;(ii) dispensar una cantidad eficaz de una solucioón polimóerica sobre la capa acuosa para formar una lónea que define una zona;incluyendo la solucióon polimóerica un polómero termoplóastico biocompatible, biodegradable, coagulable en agua, y un solvente orgaónico farmacóeuticamente aceptable, soluble en agua;(iii) aplicar una cantidad eficaz de un medio acuoso a la superficie de la lónea;y (iv) dejar que el polímero coagule para formar una lónea lómite incluyendo una estructura en dos partes compuesta de una bolsa exterior con un contenido líquido;donde el precursor de implante se forma en el sustrato de soporte dentro de la zona confinada por la lónea lómite.
- 21El móetodo seguón cualquiera de las reivindicaciones 16 a 20, incluyendo ademóas antes del paso (a), el paso de preparar una capa de soporte, incluyendo la capa de soporte un material bioabsorbible o bioerosionable;donde el precursor de implante se forma en la superficie de la capa de soporte.
- 22El móetodo seguón la reivindicacióon 21, donde la capa de soporte incluye una solucióon polimóerica recubierta sobre la superficie del tejido defectuoso;incluyendo la solucioón polimóerica un polómero termoplóastico biocompatible, biodegradable, coagulable en agua, y un solvente orgaónico farmacóeuticamente aceptable, miscible en agua.
- 23El móetodo seguón la reivindicacioón 22, incluyendo ademóas incorporar un agente formador de gas a una solucióon polimóerica, y formar la capa de soporte como una estructura porosa en forma de espuma.
- 24El móetodo seguón la reivindicacióon 21, donde la capa de soporte incluye una sustancia corporal natural. 102 T3 32
- 25El móetodo seguón la reivindicacióon 21, donde la capa de soporte incluye sangre coagulada.
- 26El móetodo seguón la reivindicacioón 21, donde la capa de soporte incluye una celulosa oxidada o gelatina.
- 27El móetodo seguón la reivindicacioón 21, donde la capa de soporte incluye un polómero soluble en agua.
- 28El móetodo seguón la reivindicacióon 21, donde la capa de soporte incluye fosfato tricaólcico, sulfato cóalcico o hidroxiapatita.
- 29El móetodo seguón la reivindicacióon 27, donde la capa de soporte consta de polilóactidos, poliglicóolidos, policaprolactonas, polianhódridos, poliamidas, poliuretanos, poliesteramidas, poliortoóesteres, polidioxanonas, poliacetales, policetales, policarbonatos, poliortocarbonatos, polifosfacenos, polihidroxibutiratos, polihidroxivaleratos, oxalatos de polialquileno, succinatos de polialquileno, óacido polimóalico, polietilen glicol, hidroxipropil celulosa, polivinil pirrolidona, poliamino aócidos, polimetil vinil óeter, quitina, quitosóan, y copolómeros, terpolómeros, y cualquier combinacióon de los mismos.
- 30Un aparato para formar un precursor de implante, incluyendo:(a) medios de soporte porosos hidróofilos para mantener una solucióon polimóerica durante la formacioón de un precursor de implante;(b) medios porosos hidróofilos para comprimir la solucióon polimóerica durante la formacióon del precursor de implante;y (c) medios para articular los medios de soporte a los medios de compresióon;estando colocados los medios de articulacióon a lo largo de un borde de los medios de soporte y los medios de compresioón;donde los medios de compresióon se pueden pivotar y colocar sobre la solucióon polimóerica en los medios de soporte.
- 31Un kit incluyendo, en combinación:(a) un aparato para formar un precursor de implante ex vivo, incluyendo: (i) medios de soporte porosos hidróofilos para mantener una solucióon polimóerica durante la formacióon de un precursor de implante;(ii) medios porosos hidróofilos para comprimir la solucióon polimóerica durante la formacióon del precursor de implante;y (iii) medios para articular los medios de soporte a los medios de compresióon;estando colocados los medios de articulacióon a lo largo de un borde de los medios de soporte y los medios de compresióon;donde los medios de compresióon se pueden pivotar y colocar sobre la solucióon polimóerica en los medios de soporte;(b) al menos unos medios espaciadores para mantener un intervalo entre los medios de soporte y los medios de compresióon del aparato cuando los medios de compresióon se pivotan y colocan en los medios de soporte;ES 2 173 102 T3 (c) un vial conteniendo una mezcla polimérica incluyendo un polímero termoplastico biocompatible, biodegradable, coagulable en agua, y un solvente organico farmaceuticamente aceptable, miscible en agua;y (d) un vial conteniendo una fuente de un medio acuoso.
- 32El kit segén la reivindicacién 31, incluyendo ademas uno o varios artículos (e)-(i):(e) medios para levantar y mantener el precur sor de implante formado;(f) medios para medir las dimensiones del tejido defectuoso o el precursor de implante;(g) unos medios de rejilla para medir las dimensiones del precursor de implante;(h) medios para cortar el precursor de implante;o (i) medios para quitar el medio acuoso de la superficie del precursor de implante. NOTA INFORMATIVA: Conforme a la reserva del art. 167.2 del Convenio de Patentes Europeas (CPE) y a la Disposición Transitoria del RD 2424/1986, de 10 de octubre, relativo a la aplicacion del Convenio de Patente Europea, las patentes europeas que designen a Espana y solicitadas antes del 7-10-1992, no producirán ningun efecto en Espana en la medida en que confieran protección a productos químicos y farmaceuticos como tales. Esta informacion no prejuzga que la patente estó o no incluóda en la mencionada reserva.
Independent claims32
157 paragraphs in 5 sections, as filed
IS 2 173 102 T3
DESCRIPTION
Bio-removable implant precursor. Background of the invention
In the course of periodontal disease, infection of gingival tissue by plaque bacteria causes the ligaments that join the gum and teeth to retract, decalcifies the bone structure that holds the roots of the teeth to the bone, and forms periodontal cavities. in the gingival tissue adjacent to the teeth. Successful periodontal restoration is known to occur if periodontal ligament cells can colonize root surfaces preferentially over gingival epithelial cells, gingival fibroblasts, or osteoblasts. However, surgery alone does not result in restoration of the lost periodontium.
In an attempt to promote and achieve periodontal restoration, implant techniques have been developed. For example, microporous membranes, such as the Millipore® filter and GORE-TEX® membranes, have been developed for use in the regeneration of periodontal tissue. Ordinarily, the periodontal fin is cut, and the microporous membrane is surgically inserted to cover the surface of the tooth root and to physically prevent epithelial cells from migrating apically along the root surface.
These membranes have several drawbacks. In addition to providing variable results, a second surgical entry is required to remove the membrane after tissue regeneration is achieved because the membranes are not biodegradable. Furthermore, there is a higher incidence of infection in connection with its use.
To avoid surgical removal of an implant, membranes made of bioabsorbable material have been used, such as microfibrillar collagen, polylactic acid, and polygalactin mesh (Vicryl®). Fitting and positioning these membranes at the implant site is cumbersome and time consuming, and the therapeutic effect of these membranes has been unpredictable. Furthermore, the degradation time of collagen composite membranes has been variable, and the risk of adverse immunological reaction to this foreign protein material in the body presents a major problem.
A liquid system containing a biodegradable polymer has been developed where the solution is injected into an implant site, and solidifies in situ to form a biodegradable implant that has a solid microporous matrix. Advantageously, the implant does not require surgical removal. However, controlled delivery and containment of a liquid system within a particular area within the implant site is difficult, and the liquid can spread to areas other than the implant site.
Therefore, there is a need for an article that facilitates the controlled placement at an implant site of a liquid polymeric solution to form an implant. Another need is to develop a precursor for a solid implant that is neither all liquid nor all solid, but which solidifies in situ to form a solid microporous implant. There is also a need for a solid implant precursor that can be applied to defective tissue in an animal and shaped or molded in situ to accommodate the defect. Another need is to develop in vivo and ex vivo methods of making an implant precursor having such characteristics.
Summary of the invention
These and other objectives are achieved with the present invention which is directed to an implant precursor for implantation in an animal, such as a human or other mammal, which would eventually harden in situ to a solid implant having a microporous matrix. The invention also provides a method of making and using the implant precursor. Also provided is an apparatus for forming an implant precursor ex vivo, and a kit containing the apparatus.
The implant precursor is a two-part structure composed of an outer bag with a liquid content. The implant precursor is comprised of a biocompatible, biodegradable and / or bioerodible water-coagulable thermoplastic polymer or copolymer, which is substantially insoluble in aqueous media, and a water-soluble, pharmaceutically acceptable organic solvent. The two-part structure of the implant precursor is formed by placing a portion of a water-coagulable polymeric solution in contact with water or other aqueous medium, after which the solvent dissipates into the aqueous medium. This causes the polymer on the surface of the polymeric solution portion adjacent to the aqueous medium to coagulate to form an outer bag that has a firm consistency on the order of gelatinous to wax-like, while the solution within the bag (i.e., the contents of the bag) remain liquid. The contents of the implant precursor bag can vary from watery to slightly viscous in consistency.
The implant precursor can be applied to an implant site in an animal, such as a void, defect, surgical incision, and analogs, in or on hard or soft tissue. Once placed in the implant site, the implant precursor eventually forms a solid microporous implant by dissipation of the organic solvent into surrounding tissue fluids and further coagulation of the polymer. Preferably, the resulting implant matrix has a two-layer pore structure with a highly porous inner core portion and a comparatively less porous outer surface layer or coating. Pores are formed in the solid matrix of the implant by dissipation of the solvent of the composition to the fluids of the surrounding tissue. Optionally, the implant precursor may include a separate pore-forming agent that is capable of generating pores within the polymeric matrix of the solid implant, such as sucrose, sodium chloride, a cellulose-based polymer, and analogs.
The resulting solid implant is biodegradable, bioabsorbable, and / or bioerodible, and will gradually be absorbed into surrounding tissue fluids, such as blood serum, lymph, cerebral spinal fluid (CSF), saliva, and anologs, and disintegrates upon through an enzymatic, chemical or cellular hydrolytic action. In gene
In ES 2, the implant will be absorbed over a period of up to about 2 years to about 3 years, preferably within about 1-9 months, preferably within about 60-180 days. The implant can be used, for example, for the selective enhancement of cell growth and tissue regeneration, the delivery of biologically active substances to the animal, and the like.
The implant precursor may also include a biologically active agent, or bioactive agent, such as, for example, an anti-inflammatory agent, an antiviral agent, an antibacterial or antifungal agent useful for treating and preventing infections at the implant site, a growth factor , a hormone, and analogs. The implant resulting from in situ coagulation of the implant precursor can then serve as a system for delivering the biologically active agent to the animal.
A release rate modifying agent may also be included in the implant precursor to control the rate of disintegration of the implant matrix and / or the rate of release of a bioactive agent in vivo from the implant matrix. Examples of substances suitable for inclusion as a release rate modifying agent include dimethyl citrate, triethyl citrate, ethyl heptanoate, glycerin, hexanediol, and the like.
The invention also includes a method of making the implant precursor. The implant precursor is formed in vivo by (a) coating the surface of a suitable support substrate with an effective amount of an aqueous medium to form a layer; (b) by dispensing onto the aqueous layer an effective amount of a liquid polymeric solution made of a water-coagulable, biodegradable thermoplastic polymer, such as polylaactide, polycaprolactone, polyglycaolide, or its copolymer, and a pharmaceutically acceptable, water-soluble organic solvent, such as N-methyl2-pyrrolidone; (c) applying an effective amount of an aqueous medium to the surface of the polymer solution; and (d) allowing the polymer adjacent to the aqueous medium to coagulate to form the implant precursor having an outer pocket with liquid content. Preferably, the thickness of the implant precursor is controlled, for example, by compressing the coagulating polymeric mass between two solid flat surfaces such as a glass sheet, porous plastic, and the like. The aqueous medium is applied to the surface of the support substrate and the surface of the polymer solution in a small, but effective amount to initiate coagulation of the polymer to form the outer pocket of the implant precursor.
The precursor is formed ex vivo by dispensing the polymeric solution onto a support substrate made, for example, of glass, a porous plastic, sintered stainless steel, porcelain, bone material, and other analogous materials.
In a variation of forming an implant precursor, an amount of the liquid polymeric solution above is applied to the surface of the support substrate to form a line that delineates a boundary around a defined area. The implant precursor can be formed after
102 T3 4 within the confines of the boundary line zone.
A support layer may optionally be applied to the surface of the tissue to provide an adhesive substrate to secure the implant precursor on the surface of the defective tissue. Useful substances for forming an adhesive backing layer include, for example, the above liquid polymeric solution, a water soluble substance such as gelatin, and the like. The support layer may be in the form of a bead, a film or coating, and the like, having a thickness as desired.
The invention also includes an apparatus for forming an implant precursor ex vivo. The apparatus is preferably a two-part assembly including support means for holding the polymeric solution on a surface during formation of an implant precursor such as a porous veneer or block, and means for compressing the polymeric solution during formation of the implant precursor. implant. Preferably, the support means and compression means are connected by hinge means positioned along an edge of the support means and compression means, such that the compression means can be pivoted and positioned over the solution. polymeric in the support means. The support means and / or compression means are preferably made of a porous material, such as, for example, a porous plastic, sintered stainless steel, porcelain, and other similar materials that are water absorbent. An aqueous medium is applied as a layer on the surface of the support means, the polymeric solution applied on the aqueous layer, and a second aqueous layer is applied on the polymeric solution. Two or more spacers, such as a washer, are preferably provided on the surface of the support means to form a defined area therebetween, and the implant precursor is formed in the area between the spacers. The compression means are then placed on the support means with the spacers and coagulating polymeric solution sandwiched in between, preferably compressing the coagulating polymeric mass. The support means and compression means of the apparatus are maintained in an interleaved arrangement until the outer pocket of the implant precursor is formed. The support means and then compression means are separated and the resulting implant precursor is removed from the apparatus, cut as desired, and placed at the implant site.
A kit is also provided containing, in combination, the precursor-forming apparatus, one or more barrier means, an amount of the polymeric solution described above in one or more vials or other containers, and an amount of an aqueous medium, preferably a saline. buffered phosphate in one or more vials or other similar container. The kit may also include forceps or other analogous means for grasping the formed implant precursor; calibrated calipers or other analogous means to measure the dimensions of the defective tissue and / or the implant precursor; a grid template or other analogous means for measuring the dimensions of the implant precursor; a scalpel, blade, or other means
ES 2 173 102 T3 analogs to cut the implant precursor to a desired size; and / or a cotton pad or other analogous means to spread the aqueous medium from the surface of the implant precursor.
The implant precursor of the invention can be used to treat defective tissue in an animal. The implant precursor can be used, for example, to enhance cell growth and tissue regeneration, wound and organ repair, nerve regeneration, soft and hard tissue regeneration, and the like. The anterior implant precursor is applied to the defective tissue and allows an implant having a solid microporous matrix to coagulate.
As used herein, the term "implant site" is understood to include a site, at or on which the implant precursor is formed or applied, such as such soft tissue such as muscle or fat, or hard tissue such as bone. Examples of implant sites include defective tissue such as a tissue regeneration site; an empty space such as a periodontal cavity, surgical incision, or other formed cavity or cavity; a natural cavity such as the oral, vaginal, rectal, or nasal cavities, the fundus, and the like; and other sites where the implant precursor can be placed and formed into a solid implant. The term "biodegradable" means that the polymer and / or polymeric matrix of the implant will degrade over time by the action of enzymes, by hydrolytic action and / or by other similar mechanisms in the human body. By "bioerodible" is meant that the implant matrix will erode or degrade over time due, at least in part, to contact with substances found in surrounding tissue fluids, cellular action, and the like. By "bioabsorbable" is meant that the polymeric matrix will decompose and absorb within the human body, for example, by a cell, tissue, and the like.
Since the implant precursor does not flow like a liquid, it provides easy manipulation and placement of a liquid polymeric system to form an implant in a selected area of defective tissue without the uncontrolled flow of the polymeric solution out of the area of the implant site. implant. The present implant precursor provides a system for forming an implant of a desired thickness, size and shape. Unlike a solid implant, the implant precursor is easy to manipulate and can be shaped and molded within the defect site as it solidifies. Advantageously, the moldability of the implant precursor allows it to conform to irregularities, fissures, fissures, holes, and the like, at the site of the tissue defect. Furthermore, the surface of the implant precursor is tacky to the touch and tends to remain in position where it is applied to defective tissue. Brief description of the drawings
Figure 1 is a perspective view of one embodiment of a precursor forming apparatus of the invention.
Figure 2 is a perspective view of the precursor forming apparatus of Figure 1, showing the placement of a series of spacers.
Figure 3 is a side view of the precursor forming apparatus of Figure 2, showing the placement of the aqueous layers and polymeric solution layer in the area between the spacers.
Figure 4 is a side view of the precursor forming apparatus of Figure 3, showing the apparatus in a closed position during formation of an implant precursor.
Detailed description of the invention
The present invention provides an implant precursor in the form of an outer bag with a liquid content for implantation in an animal. The outer pocket of the implant precursor has a firm consistency on the order of gelatinous to moldable and wax-like. The implant precursor is composed of a biodegradable, water-coagulable thermoplastic polymer in combination with a water-soluble, non-toxic organic solvent.
When implanted into the body of an animal, the organic solvent from the parent implant dissipates into the surrounding tissue fluids and the polymer coagulates to form a solid microporous implant. The resulting solid implant has a variety of uses, such as a barrier system to enhance cell growth and tissue regeneration, the delivery of biologically active agents such as drugs and medicaments, and the like.
Polymer solution
To prepare the implant precursor, a liquid polymeric solution is formulated that includes a biodegradable, water-coagulable thermoplastic polymer, such as a polylaactide, polycaprolactone, polyglycolide, or its copolymer, in combination with a water-soluble, non-toxic organic solvent. , such as N-methylpyrrolidone, as described in U.S. Patent No. 4,938,763 to Dunn et al. (issued July 3, 1990), the description of which is incorporated herein by reference. The polymeric solution can optionally include a pore-forming agent.
Polymers or copolymers are substantially insoluble in water and body fluids, and biodegradable and / or bioerodible within the body of an animal. The implant precursor and the resulting solid implant are biocompatible because neither the polymer, nor the solvent, nor the polymeric matrix causes substantial tissue irritation or necrosis at the implant site.
Thermoplastic polymers
The useful thermoplastic polymers in the liquid polymeric solution to form the implant precursor include pharmaceutically compatible polymers that are biodegradable, bioabsorbable, and soften when exposed to heat, but return to the original state when cooled. Thermoplastic polymers are capable of substantially dissolving in a water-soluble carrier, or solvent, to form a solution. Thermoplastic polymers are also capable of coagulating, or solidifying, to form an outer pocket that has a firm consistency on the order of gelatinous to wax-like, and of eventually coagulating to a solids microporous matrix upon dissipation of the solvent component of the polymer solution , and the contact of the polymer with
ES 2 173 102 T3 an aqueous medium.
Thermoplastic polymers that are suitable for use in the polymeric solution generally include those with the above characteristics. Examples are polylactides, polyglycolides, polycaprolactones, polyanhydrides, polyamides, polyurethanes, polyesteramides, polyorthoasters, polydioxanones, polyacetals, polykettals, polycarbonates, polyorthoasters, polyphosphazenes, polyhydroxybutyrates, polyhydroxyhydroxy valerates, polyhydroxybutyrates (polyhydroxyhydroxy valerates, polyhydroxy-alkylenehydroxylates, polyhydroxy valelates). (amino acids), poly (methyl vinyl ether), poly (maleic anhydride), chitin, chitosan, and copolymers, terpolymers, or combinations or mixtures. Polylactides, polycaprolactones, polyglycolides and their copolymers are highly preferred thermoplastic polymers.
The thermoplastic polymer combines with a suitable organic solvent to form a solution. The solubility or miscibility of a polymer in a particular solvent will vary depending on factors such as crystallinity, hydrophilicity, capacity for hydrogen binding, and molecular weight of the polymer. Consequently, the molecular weight and concentration of the polymer in the solvent are regulated to achieve the desired solubility. Highly preferred thermoplastic polymers are those that have a low degree of crystallization, a low degree of hydrogen bonding, low solubility in water, and high solubility in organic solvents.
Solvents
Suitable solvents for use in the thermoplastic polymeric solution are those that are biocompatible, pharmaceutically acceptable, miscible with the polymeric ingredient and water, and capable of diffusing into an aqueous medium, such as tissue fluids surrounding the implant site. , such as blood serum, lymph, cerebral spinal fluid (CSF), saliva, and the like. Preferably, the solvent has a Hildebrand solubility ratio (HLB) of from about 9-13 (cal / cm<sup>3</sup>)<sup>1/2</sup>. The degree of polarity of the solvent should be effective to provide at least about 10% solubility in water, and to dissolve the polymeric component.
Solvents that are useful in liquid polymer solution include, for example, N-methyl-2-pyrrolidone, 2-pyrrolidone, C2 to C alkanols<sub>6</sub>, propylene glycol, acetone, alkyl esters such as methyl acetate, ethyl acetate, ethyl lactate, alkyl ketones such as methyl ethyl ketone, dialkylamides such as dimethylformamide, dimethyl sulfate, dimethyl sulfone, tetrahydrofuran, alkyl calcium amides such as caprolactam, decylmethyl sulfoxide, oleic acid, propylene carbonate, aromatic amides such as N, N-diethyl-mtoluamide, 1-dodecylazacycloheptan-2-one, and the like. Preferred solvents according to the invention include N-methyl-2-pyrrolidone, 2-pyrrolidone, dimethyl sulfoxide, ethyl lactate, and propylene carbonate.
A mixture of solvents that provide varying degrees of solubility for the polymeric components can be used to increase the coagulation rate of polymers that exhibit slow coagulation or settling rate. For example, the polymer can be combined with a coagulant-promoting solvent system comprised of a mixture of a good solvent (i.e., a solvent that provides a high degree of solubility) and a poorer solvent (i.e., a solvent that provides a low degree of solubility) or a non-solvent (ie, one in which the polymer is insolvent) relative to the polymeric component. It is preferred that the solvent blend contains an effective amount of a good solvent and a poorer or non-solvent solvent, mixed in such a way that the polymer remains soluble while in solution, but coagulates as the solvents dissipate or diffuse. to surrounding tissue fluids at the implant site.
The concentration of polymer in the liquid polymer composition will generally effect rapid and effective dissipation of the solvent and coagulation of the polymer. This concentration can be on the order of from about 0.01 gram of polymer per ml of solvent to an approximately saturated concentration, preferably from about 0.1 gram per ml to approximately saturated concentration.
Upon contact with an aqueous medium such as water and the like, the solvent diffuses from the polymeric solution into the aqueous medium. This causes the polymer on the surface of the polymeric solution and adjacent to the aqueous medium to coagulate to form a two-part structure including an outer bag with a liquid content. The liquid content of the implant precursor can vary in consistency from aqueous to viscous. The outer pouch can vary in consistency from gelatinous to impressionable, moldable, and wax-like. The resulting device, or implant precursor, can then be applied to an implant site. After implantation, the solvent from the implant precursor diffuses into the fluids of the surrounding tissue to form an implant having a salid polymeric matrix. Preferably, the implant precursor solidifies in situ to a solid matrix within about 0.5-4 hours after implantation, preferably within about 1-3 hours, preferably within about 2 hours.
Pore Forming and Pore Forming Agents
When placed in an implant site in an animal, the implant precursor eventually coagulates to a salid microporous matrix structure. Preferably, the matrix is composed of a microporous inner central portion and an outer microporous coating. The pores of the inner core portion are preferably substantially uniform and the coating of the solid implant is essentially non-porous compared to the porous nature of the core. Preferably, the outer covering portion of the implant has pores with considerably smaller diameters than these pores in the inner core portion.
Pores can be formed within the implant matrix by various means. The dissipation, dispersion or diffusion of the solvent from the solidifying polymeric matrix to the fluids of adjacent tissues
ES 2 173 102 T3 cents can generate pores, including pore channels, in the polymer matrix. The dissipation of the solvent from the coagulating mass creates pores within the solid implant. The pore size of the solid implant is on the order of about 1-1000 microns, preferably the pore size of the cover layer is about 3-500 microns. The solid microporous implant has a porosity of the order of about 5-95%.
A pore-forming agent can optionally be included in the polymer solution to generate additional pores in the polymer matrix. The pore-forming agent may be any pharmaceutically acceptable organic or inorganic water-soluble substance that is substantially soluble in water and body fluids, and will dissipate from the coagulating polymeric matrix and / or the salid matrix of the implant into the surrounding body fluids. at the implant site. Porous matrices formed by the inclusion of a pore-forming agent have a pore structure in which the pores are of substantially similar size.
It is preferred that the pore-forming agent is soluble or dispersible in the organic solvent to form a uniform mixture with the polymer, as a dispersion or suspension, or as a solution. The pore-forming agent can also be a water-immiscible substance that rapidly degrades to a water-soluble substance. The pore-forming agent is preferably combined with the thermoplastic polymer and solvent in the mixture, before the matrix is formed. Suitable pore-forming agents that can be used in the polymeric composition include, for example, sugars such as sucrose and dextrose, salts such as sodium chloride and sodium carbonate, polymers such as hydroxylpropylcellulose, carboxymethylcellulose, polyethylene glycol, and polyvinylpyrrolidone, and analogs. Salid crystals that will provide a defined pore size, such as salt or sugar, are preferred.
When the implant precursor is applied to an implant site, the solvent and / or pore-forming agent dissipates into the surrounding tissue fluids. This causes the formation of microporous channels within the coagulating polymeric matrix. Optionally, the pore-forming agent can dissipate from the matrix into the surrounding tissue fluids at a slower rate than the solvent, or be released from the matrix over time by biodegradation or bioerosion of the matrix. The pore-forming agent preferably dissipates from the coagulating implant matrix within a short time after implantation such that a matrix is formed with effective porosity and pore structure to accomplish the particular purpose of the implant, such as , a barrier system for a tissue regeneration site, a matrix for the timed release of a drug or medicament, and the like.
The porosity of the salid implant matrix can be varied by the concentration of water-soluble or water-miscible ingredients, such as the solvent and / or pore-forming agent, in the polymeric composition. For example, a high concentration of water soluble substances in the thermoplastic composition can produce a polymeric matrix that has a high degree of porosity. The concentration of the pore-forming agent relative to the polymer in the composition can be varied to achieve different degrees of pore formation, or porosity, in the matrix. In general, the polymeric composition will include about 0.01-1 gram of pore-forming agent per gram of polymer.
The size or diameter of the pores formed in the solid implant matrix can be modified according to the size and / or distribution of the pore-forming agent within the polymeric matrix. For example, relatively insoluble pore-forming agents can be selectively included in the polymer blend in the polymer composition based on particle size to generate pores having a diameter that corresponds to the size of the pore-forming agent. Pore-forming agents that are soluble in the polymer mixture can be used to vary the pore size and porosity of the implant matrix by the distribution and / or aggregation configuration of the pore-forming agent within the polymer mixture and coagulate a salid polymeric matrix.
When the implant is used to promote guided tissue regeneration, it is preferred that the diameter of the pores in the matrix is effective to prevent the growth of epithelial cells and enhance the growth of cells of connective tissue to the implant polymeric matrix. It is also preferred that the pore size and porosity of the implant matrix facilitate the diffusion of nutrients and other growth promoting substances such as growth factors, to the cells that have grown in the matrix. The degree of porosity of the matrix preferably provides an implant that is capable of substantially maintaining structural integrity for the desired period of time without breakage or fracture during use.
To provide an effective implant for bone cell regrowth and tissue regeneration, it is preferred that the diameter of the pores of the implant is about 3-500 microns, more preferably about 3200 microns, most preferably about 75-150 microns. It is also preferred that the matrix have a porosity of about 595%, preferably about 25-85%, to provide optimal cell and tissue growth to the matrix and optimal structural integrity.
The diameter and the distribution of the pores within the polymer matrix of the solid implant can be measured, for example, following scanning electron microscopy methods by examining cross sections of the polymer matrix. The porosity of the polymeric matrix can be measured using suitable methods known in the art, such as mercury introduction porosimetry, specific gravity or density comparisons, scanning electron microscope photo calculation, and the like. Porosity can also be calculated following the proportion or percentage of water soluble material included in the component.
ES 2 173 102 T3 polymeric position. For example, a polymer composition containing approximately 30% polymer and approximately 70% solvent and / or other water soluble components will generate an implant having a polymer matrix of approximately 70% porosity.
Biologically active agent
The polymeric solution may optionally include a biologically active agent, alone or in combination, such that the implant precursor and implant provide a delivery system for the agent to adjacent or distant tissues and organs in the animal. Biologically active agents that can be used alone or in combination in the implant and implant precursor include, for example, a medicament, drug, or other suitable biologically, physiologically, or pharmaceutically active substance that is capable of providing biological, physiological, or therapeutic effect. local or systemic in the body of an animal including a mammal, and being released from the solid implant matrix into adjacent or surrounding tissue fluids.
The biologically active agent can be soluble in the polymeric solution to form a homogeneous mixture, or insoluble in the polymeric solution to form a suspension or dispersion. After implantation, the biologically active agent is preferably incorporated into the implant matrix. As the matrix degrades over time, the biologically active agent is released from the matrix into adjacent tissue fluids, preferably at a controlled rate. The release of the biologically active agent from the matrix can be varied, for example, by the solubility of the biologically active agent in an aqueous medium, the distribution of the agent within the matrix, the size, shape, porosity, solubility and biodegradability of the matrix. implant, and analogs.
The polymeric solution, implant precursor, and implant include the biologically active agent in an amount effective to provide the desired level of biological, physiological, pharmacological, and / or therapeutic effect in the animal. There is a generally non-critical upper limit on the amount of the bioactive agent included in the polymeric solution. The only limitation is a physical limitation for advantageous application, that is, the bioactive agent should not be present in such a high concentration that the solution or viscosity of the dispersion is too high for injection. The lower limit of the amount of bioactive agent incorporated into the polymeric solution will depend on the activity of the bioactive material and the desired period of time for treatment.
The biologically active agent can stimulate a biological or physiological activity in the animal. For example, the agent can act to enhance cell growth and tissue regeneration, birth control function, produce nerve stimulation or bone growth, and the like. Examples of useful biologically active agents include a substance, or its metabolic precursor, that is capable of promoting cell and tissue growth and survival, or enhancing cell function, such as a nerve growth promoting substance. such as a ganglioside, a nerve growth factor, and the like; a hard or soft tissue growth promoting agent such as fibronectin (FN), human growth hormone (HCH), interleukin 1 proteon growth factor (IL-1), and the like; a bone growth promoting substance such as hydroxyapatite, tricaolic phosphate, and analogs; and a substance useful to prevent infection at the implant site, such as, for example, an antivorous agent such as vidarabine or acyclovir, an antibacterial agent such as a penicillin or tetracycline, an antiparasotic agent such as quinacrine or chloroquine.
Biologically active agents suitable for use in the invention also include anti-inflammatory agents such as hydrocortisone, prednisone, and anaologs; antibacterial agents such as penicillin, cephalosporins, bacitracin, and analogs; antiparasotic agents such as quinacrine, chloroquine, and the like; antifungal agents such as nystatin, gentamicin, and anaologs; antiviral agents such as acyclovir, ribarivin, interferons, and the like; antineoplastic agents such as methotrexate, 5-fluorouracil, adriamycin, toxin-conjugated tumor-specific antibodies, tumor necrosis factor, and anaologs; analgesic agents such as salicholic acid, acetaminophen, ibuprofen, flurbiprofen, morphine, and anaologs; local anesthetics such as lidocaone, bupivacaone, benzocaone and analogs; Vaccines such as hepatitis, flu, measles, rubella, tethane, polio, rabies, and analogs; central nervous system agents such as a tranquilizer, β-adrenoceptor blocking agent, dopamine, and anaologs; growth factors such as colony-stimulating factor, platelet-derived growth factor, fibroblast growth factor, transforming growth factor B, human growth hormone, bone morphogenetic proteon, insulin-like growth factor, and anaologs; hormones such as progesterone, follicle stimulating hormone, insulin, somatotropins, and analogs; antihistamines such as diphenhydramine, chlorphencramine, and the like; cardiovascular agents such as digitalis, nitroglycerin, papaverine, streptokinase, and analogs; antiulcer agents such as cimetidine hydrochloride, isopropamide iodide, and anaologs; bronchodilators such as metaproternal sulfate, aminophylline, and anaologs; vasodilators such as theophylline, niacin, minoxidil, and anaologs; and other analogous substances. For other examples of biologically active agents that can be used in the present invention, see Applicant's US Patent Application No. 07 / 783,512, filed October 28, 1991, the disclosure of which is incorporated herein by reference.
Accordingly, the formed implant can function as a delivery system for drugs, medicaments, and other biologically immune agents to tissues adjacent or distant from the implant site. The biologically active agent is preferably incorporated into the polymeric matrix, and then released to the surrounding tissue fluids and the relevant body tissue or organ.
IS 2 173 102 T3
Control of the release of the bioactive agent
The rate of implant disintegration and / or release of a bioactive agent in vivo can be controlled by varying the type and molecular weight of the polymer (s), including a release rate modifying agent, and / or by varying the combination. and concentrations of ingredients that make up the polymer solution.
The release rate of a bioactive agent from the implant matrix can be modified by varying the molecular weight of the polymer included in the polymer solution. It has been found that for implant matrices formed by the above liquid polymeric solution, the release rate of a bioactive agent follows a "U" shaped curve as the molecular weight of the polymer increases. That is, the release rate of the bioactive agent decreased, passed through a mononym, and then increased again as the molecular weight of a polymer increased. As a result, a polymeric solution can be formulated with an optimal polymer molecular weight band for the release of a bioactive substance over a selected period of time. For example, to achieve relatively rapid release of a bioactive agent from the implant matrix, a molecular weight of the polymer was used on both sides of the mononym for that particular polymer in the polymer solution. For the release of a bioactive agent over a relatively long period of time, a polymer molecular weight thereof or approximately the same for the particular polymer was preferred.
With the polymeric system present, the minimum topical release rate of a bioactive agent from the solid implant matrix occurs at an inherent viscosity (IV in deciliters / g) of approximately 0.2, but may vary depending on the ingredients of the implant. polymeric solution. To achieve sustained release of the bioactive agent from the implant matrix, it is preferred to adjust the molecular weight of the polymer to at least about 0.1 inherent viscosity (I. V.) or approximately 2,000 molecular weight determined by gel permeation chromatography (comparison with polystyrene). Acceptable sustained release rates are ordinarily obtained if the molecular weight of the polymer is less than about 0.8 IV, or a molecular weight of about 100,000. Most preferably, the molecular weight is regulated so that it is within a range of about 0.1-0.5 IV, for effective sustained release. For a poly (DL-lactide) or a loactide-co-glycolide system, the desired molecular weight range is approximately 0.10.5 IV If the molecular weight of a specific polymer is chosen from these parameters and the release of the bioactive substance is too slow or too fast, the speed can be varied simply by determining a few experimental points along the U curve for said polymer and regulating the molecular weight accordingly.
The molecular weight of a polymer can be varied by any of several methods known in the art. The choice of method is determined topically by the type of polymer solution formulated. For example, if a thermoplastic polymer is used that is biodegradable by hydrolysis, the molecular weight can be varied by controlled hydrolysis, such as in a steam autoclave. Topically, the degree of polymerization can be controlled, for example, by varying the number and type of reactive groups and the reaction times.
For other examples and a further explanation of controlling the rate of release of a bioactive agent from the implant matrix by varying the polymer composition of the polymer solution, see Applicant's corresponding United States Patent Application, number 07 / 776,816, filed. on October 15, 1991, the description of which is incorporated herein by reference.
Release rate modifying agents
The polymer solution may include a release rate modifying agent to effect sustained controlled release of a bioactive agent from the solid implant matrix. Although not intended to limit the present disclosure, the release rate modifying agent is considered to alter the release rate of a bioactive agent from the implant matrix by changing the hydrophobicity of the polymeric implant.
The use of a release rate modifying agent can decrease or increase the release of the bioactive agent in the range of multiple or orders of magnitude (e.g., 1 to 10 to 100), preferably up to a ten-fold change, compared to the release of a bioactive agent from a solid matrix without the release rate modifying agent. For example, naltrexone and doxycycline are released substantially completely from a polymeric matrix composed of poly (DL-lactide) in a period of about 2-3 days ex vivo. With the addition of a release rate modifying agent such as ethyl heptanoate which is hydrophobic to the polymeric solution, and the formation of the implant matrix by interaction of the polymeric solution and an aqueous medium, the release rate of naltrexone or doxycycline can be slowed to produce substantially complete drug release within approximately seven days. With the inclusion of a larger amount of a release rate modifying agent in the polymer solution, the release time period can be increased to approximately fourteen days. Other release rate modifying agents that are hydrophilic, such as polyethylene glycol, can enhance the release of the bioactive agent. By an appropriate choice of the molecular weight of the polymer in combination with an effective amount of the release rate modifying agent, the release rate and the extent of release of a bioactive agent from the implant matrix can be varied, for example, from relatively fast to relatively slow.
The speed modifying agents
Useful releases include, for example, organic substances that are water-soluble, water-miscible, or water-insoluble (ie, water-immiscible), with water-insoluble substances being preferred. The release rate modifying agent is preferably an orgone compound which replaced the complementary molecule with the secondary valence bond between polymorphic molecules, and increases the flexibility and ability of the polymeric molecules to slide relative to each other. Such an organic compound preferably includes a hydrophobic and a hydrophilic region to effect secondary valence bonding. It is preferred that a release rate modifying agent be compatible with the combination of polymers and solvent used to formulate the polymeric solution. It is also preferred that the release rate modifying agent is a pharmaceutically acceptable substance.
Useful release rate modifying agents include, for example, fatty acids, triglycerides, other analogous hydrophobic compounds, orgaonic solvents, plasticizer compounds, and hydrophilic compounds. Suitable release rate modifying agents include, for example, esters of mono-, di-, and tricarboxylic acids, such as 2-ethoxyethyl acetate, methyl acetate, ethyl acetate, diethyl phthalate, dimethyl phthalate, dibutyl phthalate, dimethyl adipate, dimethyl succinate, dimethyl oxalate, dimethyl citrate, triethyl citrate, acetyl tributolic citrate, acetyl trietholic citrate, glycerol triacetate, di (n-butyl) sebecate, and anologs; polyhydroxy alcohols, such as propylene glycol, polyethylene glycol, glycerin, sorbitol, and the like; fatty acids; glycerol triesters, such as triglycerides, epoxidized soybean oil, and other epoxidized vegetable oils; sterols, such as cholesterol; alcohols, such as Cg-C alkanols<sub>12</sub>, 2-ethoxyethanol, and the like. The release rate modifying agent can be used alone or in combination with other agents. Suitable combinations of release rate modifying agents include, for example, glycerin / propylene glycol, sorbitol / glycerin, ethylene oxide / propylene oxide, butylene glycol / adipic acid, and analogs. Preferred release rate modifying agents include dimethyl citrate, triethyl citrate, ethyl heptanoate, glycerin, and hexanediol.
The amount of the release rate modifying agent included in the polymeric solution varied according to the desired rate of release of the bioactive agent from the implant matrix. Preferably, the polymer solution contains about 0.5-15%, preferably about 5-10%, of a release rate modifying agent.
For other examples and further explanation of release rate modifying agents, or rate modifying agents, for use in the present invention, see Applicant's corresponding United States Patent Application, number 07 / 776,816, filed 15 October 1991, the description of which is incorporated herein by reference.
102 T3 16
Other factors to modify the release rate
The release rate of the bioactive agent from the implant matrix can also be adjusted by varying the concentration of the polymer in the polymeric solution. For example, the more dilute the polymer concentration, the more easily the bioactive agent was released from the implant matrix. For example, in a system containing approximately 5% flurbiprofen and a polymer concentration of approximately 55% poly (DL-lactide), a cumulative release of approximately 11.4% on day 1 and approximately 23% on day 1 can be expected. Day 7. With a polymer concentration of approximately 45%, the cumulative percent release is approximately 23% at day 1 and approximately 40% at day 7.
This effect can be used in combination with other means to more effectively control the release of the bioactive agent from the implant matrix as desired. For example, by regulating the concentration of the polymer and / or the bioactive agent, along with controlling the molecular weight and the amount of the release rate modifying agent, a wide range of release rates can be achieved.
The rate of release of a bioactive agent from the implant matrix can also be varied by the addition of additives such as a pore-forming agent, as explained herein. Implant precursor formation
Various methods can be used to form the implant precursor. In general, the implant precursor is formed by dispensing a portion of the liquid polymer solution onto the surface of a support substrate. Then an aqueous medium is placed in contact with the polymeric solution. Solvent is then diffused from the polymeric solution and the aqueous medium diffuses into the solution. This causes coagulation of the polymer together with the aqueous medium to form the outer pocket of the implant precursor.
Suitable support substrates include, for example, glass, stainless steel, porcelain, solid plastics, or porous plastics. These ex vivo materials may optionally have a bonded layer of a different material, such as a nylon filter, or a coating or a surface treatment or additive that allows the support to absorb or wick an aqueous medium. Aqueous media that can be used ex vivo include water and saline solutions. Other aqueous media can be used if they cause coagulation of the polymeric solution and are clonically acceptable.
The aqueous medium may be present on the surface of the supporting substrate or within the supporting substrate prior to dispensing of the polymeric solution or the aqueous medium may be applied on top of and around the polymeric solution after it is in place. The coagulation of the lower surface of the polymeric solution requires in the latter case that the aqueous medium advance below the polymeric solution.
The amount of aqueous medium used and the time that the polymeric solution and the aqueous medium are kept in contact depends on the
ES 2 173 102 T3 composition of the polymeric solution and the aqueous medium, the nature of the support substrate, the geometry of the apparatus, the quantity and dimensions of the polymeric solution and the desired consistency for the implant precursor. For a given procedure and set of materials, the consistency of the implant precursor can be varied from gelatinous to formable and impression retention to fairly rigid by increasing the time that the polymeric solution and aqueous medium are in contact. After forming the implant precursor, the aqueous medium can be removed by rocking the holder and / or the implant precursor to allow the aqueous layer to come off or by spreading the aqueous layer with an absorbent material such as a cotton swab, gauze pad. or a sponge. The implant precursor can then optionally be trimmed to the desired size and shape and then placed in the implant site. It is cut and implanted into the animal within about 1 to 60 minutes, preferably 1 to 10 minutes, of the completion of the coagulation process. If not implanted or recontacted with an aqueous medium, the implant precursor softened and eventually returned to a completely liquid phase, typically after 30-90 minutes of formation. This process is produced by an interaction between the outer bag layer and the liquid content. The solvent and aqueous medium are redistributed in the implant precursor that destroys the pocket formed in the coagulation process and gives rise to a continuous liquid phase.
The dimensions of the implant precursor can be controlled with various methods. It is preferred that the thickness of the implant precursor is about 300-1500 µm, preferably about 600-1200 µm. The desired length and width depend on the dimensions of the implant site in the animal. In preferred methods the thickness is controlled during the coagulation process and the length and width are controlled in a subsequent cutting step. The polymeric solution is dispensed onto a flat support substrate and a second flat piece of support substrate is placed on top of the polymeric solution and pushed down causing the polymeric solution to thin and spread until the desired interval is obtained between the support substrates. This interval can be defined by spacers that keep the pieces of the support substrate or other means apart. The aqueous medium can be present during this process or applied after this process. Coagulation of the polymeric solution in this defined space results in a sheet of implant precursor material with a central section of substantially uniform thickness with more thin portions at the edges. The implant precursor is cut after the central section of the blade using a razor blade, surgical precursor blade, scalpel, or other means. This cutting step allows the length, width and shape of the implant precursor to be controlled.
Alternative methods of controlling the dimensions of the implant precursor include dispensing the polymeric solution onto a support substrate in which the desired area (ie, width, length) has been defined by some type of barrier. It can then be controlled as previously described or by dragging a flat stem such as a spatula across the surface of the coagulating polymeric mass or anaologous means. The polymeric solution can also be dispensed to a recessed or void area, such as a pre-molded die or mold or template, or other analog device, having the dimensions (i.e., width, length, depth, or thickness) of the precursor. implant. Additional amounts of the polymeric solution can be applied to the surface (s) or edges of the coagulating polymeric mass to adjust the dimensions.
Various devices can be used to form the implant precursor. Such a device, which can be used ex vivo, is a "clamp cleaner". A "clamp cleaner" is constructed by attaching a sheet metal with a hole or wire loop to a clamp blade at right angles to the clamp blades in such a way that the second blade sweeps the surface of the plate or loop of wire when the gripper blades are apart. The veneer or wire loop is positioned on the support substrate ex vivo so that the hole in the veneer or the interior of the wire loop defines the area for the implant precursor. The polymeric solution is then dispensed to this area and leveled to control thickness by passing the second blade of the clamp over the polymeric solution. Then an aqueous medium is applied to produce coagulation. Alternatively, the aqueous medium is applied prior to the leveling procedure. Once the implant precursor has sufficiently coagulated, the "clamp cleaner" is removed from the substrate. The resulting implant precursor can be used according to the method of the invention.
In another embodiment of the invention, an implant precursor can be formed ex vivo by forming a boundary lone on the surface of the support substrate to contain the polymeric solution within a confined zone. To form the boundary line on a substrate, an amount of water or other aqueous medium is applied as a coating on the surface of the supporting substrate, the polymeric solution is dispensed as a line onto the water layer to define a confined zone, and Afterwards, a quantity of water is applied to the surface of the polymeric solution, giving rise to the surface coagulation of the polymeric solution. The resulting lone boundary is a two-piece, tube-shaped structure made of an outer bag with a liquid center. An implant precursor can then be formed within the confines of the boundary zone by dispensing an amount of the polymeric solution onto an aqueous layer coated on the support substrate within the boundary zone, and applying an aqueous medium to the polymeric layer. to form the two-part structure of the implant precursor.
Implant precursor forming apparatus
According to the invention, a preferred method of making an implant precursor ex vivo is by using an apparatus, such as that shown generally in Figure 1. It is understood, however, that various shapes, sizes, and arrangements of the apparatus form
ES 2 implant precursor are possible according to the invention.
Figure 1 is a schematic drawing of the preferred apparatus design, shown closed as it would be during the coagulation process. The apparatus consists of a box consisting of upper and lower sections (1 and 2) that are held together by a hinge (3) at one end and a retention mechanism (4 and 5) at the other end. Each section contains a porous hydrophilic plastic sheet (6 and 7). When the box is closed, the two sheets of porous hydrophilic plastic (6 and 7) are kept separated by spacers (8 and 9) as shown in figure 1. This apparatus is used by opening the box and filling the pores in the hydrophilic porous plastic sheets (6 and 7) with an aqueous medium. The polymeric solution is then dispensed onto the porous hydrophilic plating sheet in the lower half of the box (7) and the box is closed as shown in figure 1. The spacers (8 and 9) define the interval in which the polymeric solution is maintained during the coagulation process and therefore control the thickness of the implant precursor. Once the desired coagulation has been performed, the cage is opened and the implant precursor is cut and then implanted.
Figure 2 details the preferred embodiment of the general design of the apparatus shown in figure 1. The components are marked with the same numbers as in figure 1. This embodiment contains a section (10) that is not present in figure 1. It is a shear grid that is a portion of the box bottom (2). The box consists of upper and lower sections (1 and 2) joined with a hinge (3) formed by jump joining the two box sections. The box is made of a gamma resistant polypropylene. Alternative box materials could be used that can resist contact with the polymeric solution and gamma radiation sterilization and are quite rigid. The latch mechanism is made up of the portions (4 and 5) of the two box sections (1 and 2) that snap together and easily separate to allow the box to open and close and keep the box tightly closed during the coagulation process. The hydrophilic porous plaostic sheets (6 and 7) are rigid flat sheets with the hydrophilicity and porosity necessary to allow an aqueous medium to fill the pores of the sheet and then allow the exchange of the aqueous medium and the solvent between the polymeric solution and the medium. aqueous and solvent between the polymeric solution and aqueous medium in the pores during the coagulation process. The porosity of the sheet is a factor that controls the rate of coagulation. The porous plastic can be of an inherently hydrophilic polymer or a mixture of a hydrophobic polymer mixed with or treated with a surfactant or other agent that increases hydrophilicity. The material used in the preferred embodiment is a polyethylene mixed with a surfactant. The spacers (8 and 9) are gamma resistant polypropylene rectangles.
The cutting grid (10) is a flat portion of the lower box section (2). After the coagulation process, the implant precursor is placed on the cutting grid where it is cut.
102 T3 20 to the desired shape, length, and width using a surgical prep blade, razor blade, or other anaologous means. The cutting grid has a 1mm square configuration that contributes to cutting to the desired dimensions. This configuration may be present as part of the box itself or printed on the box or printed on a label that is then attached to the box. The configuration is printed in the preferred embodiment on a clear label which is affixed to the underside of the box bottom (2). The settings are visible through the light to slightly blurred box bottom (2) and the clear label material. Placing the label or imprint on the bottom side of the box eliminates the possibility of phosphoric or chemical interaction of the implant precursor and the label or imprint.
The dimensions of the apparatus depend on the desired dimensions of the implant precursor. For the production of an implant precursor approximately 675 µm thick with a length and width of approximately 20mm or less, the following approximate dimensions are suitable. The spacers (8 and 9) are 675 µm thick, 0.5 cm wide, and 2.5 cm long. Porous plaostic sheets are 4.5 cm long and 3.0 cm wide with a thickness of 0.3 cm. The configuration of the cutting grid (10) is 3.5 cm by 3.5 cm. The box sections (1 and 2) are approximately 7.5 cm by 5 cm with cavities for the porous plastic sheets (6 and 7) 30 cm deep. For proper thickness control, the box should be designed to close so that the spacers (8 and 9) are held tightly between two porous platosis sheets (6 and 7) so that coagulation occurs in a range. that corresponds to the thickness of the spacers.
Adhesive layer
To improve the adhesion of the implant precursor at the implant site, an adhesive layer can be applied to the tissue surface and the formed implant precursor is then placed on the support layer. The adhesive layer preferably contributes to maintaining the position of the implant precursor when coagulating to a solid matrix at the implant site. The adhesive layer includes a bioabsorbable, biodegradable and / or bioerodible substance capable of adhering to surfaces of the defective tissue and to the surface of the implant precursor. An adhesive layer can be formed, for example, by applying a small but effective amount of the above liquid polymeric solution in the form of a bead or as a coating on the surface of the defective tissue.
Support layer
To maintain the structure and shape of the implant precursor, a support layer can be applied to the tissue surface and the formed implant precursor is then placed on the support layer. Suitable materials for use in forming a support layer include, for example, a natural body material such as a blood clot or other body fluid, a water-soluble substance such as gelatin, or a water-soluble polymer, such as, po
ES 2 173 102 T3 livinyl pyrrolidone, and other analogous materials.
A supporting layer of clotted blood can be formed, for example, by piercing the tissue with a needle to generate a secondary, but effective, flow of blood that is then allowed to clot. A formed implant precursor can be applied to the surface of the support layer at the implant site.
In another embodiment, granules or small pieces of a biodegradable porous material such as polylactic acid, oxidized cellulose or gelatin and the like can be used to fill a defective or void tissue, and then a formed implant precursor can be applied to the granular material of medium.
Another useful support layer is a solid matrix having a porous foam-like structure. Such a matrix can be obtained, for example, by mixing air into the above polymeric solution to provide a foamy consistency, and allowing the mixture to coagulate to a matrix having relatively large pores and / or cavities. Air bubbles can be incorporated into the polymeric solution, for example, by vigorously shaking the polymeric solution, blowing air into the solution using a syringe, and other analogous means. It is preferred to apply an aqueous medium to the surface of the foamed mixture to cause the polymer to coagulate to form a matrix having large cavities.
Large pores can also be obtained in a solid support matrix by combining the polymeric solution with a gas-forming agent, such as, for example, a mixture of catric acid and sodium carbonate or bicarbonate. When contacted with an aqueous medium, the gas-forming agent reacts to form gas bubbles such as carbon dioxide within the coagulating polymeric matrix.
Where a void space between the defective tissue and the solid implant is desirable, the support layer is preferably formed of a water soluble and / or highly resorbable material. For example, the support layer may include a water soluble substance that will dissolve within a few days, such as an oxidized cellulose or gelatin material such as Surgicel ™ or Gelfoam ™, available from Johnson & Johnson Company and Upjohn Company; a water soluble polymer such as polyvinyl pyrrolidone, polyethylene glycol, and hydroxypropyl cellulose, and the like; and other analogous substances. Preferably, the water soluble support layer will dissolve within about 1-14 days, preferably about 2-4 days, after implantation of the implant precursor.
In cases where it is desired to promote tissue growth to a substrate at the implant site, it is preferred that the support layer includes a porous material that has a relatively longer rate of degradation. Suitable materials include, for example, a polylactic acid material typically applied to molar extraction sites to inhibit dry cavities, such as Drilac ™ which is commercially available from THM Biomedical, Inc. and a hydroxyapatite material such as Interpore 200 commercially available from Interpore International. Advantageously, a support layer made of a porous material such as polylactic acid or hydroxyapatite, allows blood to infiltrate and coagulate within the matrix providing a source of nutrients to promote tissue growth. It is noted that growth of the tissue to the support matrix would eventually break down the support layer.
Kit to form an implant precursor
The invention also includes a kit for forming an implant precursor ex vivo. The kit includes, in combination, (i) a precursor-forming apparatus, as described above, which is preferably a two-part apparatus hinged along one side; (ii) one or more spacer means for maintaining an interval or space between the two halves of the apparatus, for example, a washer, rod, block, and analogs; (iii) one or more vials or other analogous means containing the polymeric solution described above; and (iv) one or more vials or other analog media containing an aqueous medium source such as water, phosphate buffered saline, and analogs. The kit may also include forceps or other analogous means for lifting and holding the formed implant precursor; a device for measuring the dimensions of the defective tissue and / or the implant precursor, such as calibrated and analog calipers; a grid template and other analogous means for measuring the dimensions of the implant precursor; a scalpel, razor blade, or other analogous means for cutting and sizing the implant precursor; and / or a pad of cotton wool or other analogous means for removing the aqueous medium from the surface of the implant precursor.
Use of the implant precursor
The implant precursor can be used to treat various defective tissues. The implant precursor can be applied to an implant site in an animal, such as a void, defect, surgical incision, and analogs, in hard or soft tissue, by known surgical techniques.
Preferably, once placed at the implant site, the implant precursor would coagulate substantially to a solid, but moldable matrix, within about 0.5-4 hours, more preferably about 0.75-3 hours, even more preferably about 1-2 hours.
For example, the implant precursor can be used in a method of treating an bone tissue defect such as a bone fracture of the arm or leg, a tooth defect, and analogous. Preferably, the bone tissue is surgically separated from the adjacent soft tissue to expose the defect, and the implant precursor is placed in the bone defect, after the implant precursor hardens in situ to a solid implant.
In a preferred use according to the invention, the implant precursor can be used as a barrier system for guided tissue regeneration. The implant precursor is formed outside the body of the animal and then delivered to an implant site such as tissue with a vacuum
ES 2 such as a periodontal cavity, a soft tissue defect, a surgical incision, a bone defect and anaiogos. Once administered to the tissue regeneration site, the implant precursor will solidify to form a solid microporous matrix that provides a surface on which the cell can grow. To enhance the regeneration of hard tissue such as bone tissue, it is preferred that the solid implant matrix provides support for the new cell growth that will replace the matrix when it is gradually absorbed or eroded by body fluids.
An example of using the implant precursor as a barrier system is in the treatment of periodontal disease. For such treatment, the gingival tissue lining the tooth root is surgically cut from the root of the tooth and bone to form a gingival tissue envelope or cavity, and an implant precursor is placed in the cavity and against the bone. After placement, the tissue is sutured to close the cavity, and the implant precursor is allowed to harden to a solid microporous implant.
The implant precursor can be manipulated at the implant site to conform to the contours of the defective tissue. For example, in a periodontal defect, the gingival tissue flap can be pushed over the solidifying implant matrix positioned against the exposed root and bone, and pressure applied to the surface of the overlay tissue over the solidifying matrix. The solidifying matrix is malleable and such manipulation conforms the implant on one side to conform to the defective tissue and on the other side to the contours of the covering tissue. The tissue can be removed to determine the profile (ie, shape) of the implant matrix and, optionally, additional amounts of the polymeric solution can be added to form the matrix and fill in irregularities when necessary. In cases where the implant precursor is too large, a portion of the coagulant matrix can be cut along the edges of the overlay tissue, such as just above the lone of the cavity. gingival tissue. The tissue can then be fixed in position on the implant matrix, for example, by suturing the tissue at both ends of the socket to hold the tissue and the implant in position.
To facilitate adhesion of the implant precursor to the surface of the defective tissue, a bead or coating of the above polymeric solution can be applied over the defect to provide a tacky surface. The implant precursor or liquid polymer solution can then be applied to the bead or coating surface.
The implant precursor can be used to attach a skin graft to underlying wound tissue; and such use of the implant precursor helps prevent seroma or hematoma formation, and accelerate the healing process. Preferably, the implant precursor includes a topical antibiotic agent.
The implant precursor can also be used to improve the closure of a surgical incision, such as a through incision.
102 T3 24 of the sternum for open heart surgery, stabilizing the sternum and promoting healing. In such use, the implant precursor is applied to both sides of the sternum prior to closure of the sternum with metallic threads and / or sutures. Preferably, the implant precursor includes a growth factor and / or an antibiotic agent.
Advantageously, the implant precursor provides a means of adhering an implant article to tissue generally covered with a mucous layer, such as gingival tissue. In addition, the implant precursor performs the application of a liquid polymeric solution to an implant site without the uncontrolled flow of fluid to areas other than those identified for treatment. For example, in the treatment of a periodontal defect, the use of the present implant precursor advantageously avoided the accumulation of a polymeric solution in the spaces between the roots of the tooth and the periodontal region where the ligament cells are located. The present precursor implant also facilitates a better fit of a barrier implant in a defect site tissue than other devices known and used in the art.
The microporous polymeric matrix of the implant is capable of biodegradation, bioerosion and / or bioabsorption within the implant site of the animal. The particular polymer and the molecular weight of the polymer can be varied according to the desired duration or time interval to maintain the solid polymeric matrix within the implant site, such as from a few days or weeks to several years. When the implant is used to enhance cell growth and tissue regeneration, it is preferred that the polymeric matrix disintegrates at an effective rate to allow displacement of the matrix by the cell growth of adjacent cells or tissue.
The formulation of the liquid polymeric solution to prepare the implant precursor, and the administration of the implant precursor in vivo will ultimately be according to the judgment and protocol of the medical professional attending the patient such as a surgeon, or if appropriate, a dentist. The choice of the particular formulation of ingredients was made by the attending healthcare professional. Without a bioactive agent, the solid implant resulting from the implant precursor can function as a structure for the promotion of cell growth and tissue repair. With a bioactive agent, the implant will not only function in such capacity, but will also have the properties of the bioactive agent.
The amounts and concentrations of ingredients in the implant precursor administered to the patient will generally be effective to perform the intended task. If said task is to fill a void space, an implant precursor of an appropriate size and an effective amount of ingredients was administered to accomplish this task. For the administration of a bioactive agent, the amounts and rates of release will follow the recommendations of the manufacturer of the bioactive agent. In general, the concentration of a bioactive agent in the polymeric solution
ES 2 173 liquid will be about 0.01-400 mg per gram of polymer solution.
The invention will be described with reference to various specific and preferred embodiments and techniques. However, it should be understood that many variations and modifications can be made while remaining within the spirit and scope of the invention.
Example 1
Ex vivo formation of an implant precursor 10 with a porous polyethylene substrate
A polymer blend will be prepared including approximately 37% poly (DL-lactide) (DLPLA) and approximately 63% N-methyl-2-pyrrolidone (nmp). DL-PLA had a molecular weight of approximately 65,000 daltons (inherent viscosity in chloroform of approximately 0.50 dL / g). Polypropylene containers were filled with this polymer blend such that each contained approximately 0.8 g of the polymer blend. These filled containers were then sterilized by exposure to gamma radiation at a level of 25-35 kGy, resulting in a final molecular weight of DL-PLA of approximately 38,000 daltons (inherent viscosity in chloroform of approximately 0.34 dL / g ).
The apparatus depicted diagrammatically in Figure 2 was used to form an implant precursor from the liquid polymer blend. The porous polyethylene substrates on each side of the box were saturated with approximately 2.5 ml of sterile saline. Two polypropylene spacers were placed on the porous polyethylene substrate in the lower half of the box (closest to the shear grid) in such a way that they were<sub>35 </sub>They are parallel to the articulation of the box and against the edges of the porous polyethylene substrate. A container filled with the polymeric mixture will be opened, and the contents (approximately 0.6 g) will be expelled onto the center of the porous polyethylene substrate between the spacers. The box was closed and locked, then reopened after six minutes. The semi-rigid article was removed from the porous polyethylene substrate, placed over the bonded cut zone, and cut to size 45 using a sterile blade.
The implant precursor was visually examined; it was opaque, semi-rigid and flexible. The implant precursor had a two-part structure consisting of a gel-like outer layer.<sub>50 </sub>semi-rigid and a more liquid central nucleus. Chemical analysis indicates that the implant precursor contains approximately 58% MPN. Example 2
In vitro formation of an implant precursor 55
An implant precursor will be formed as in Example 1 above, except that the box remained closed for eight minutes. This item was stiffer than the item in Example 1 above. 60
Example 3
In vitro formation of an implant precursor
An implant precursor will form as in Example 1 above, except that the box remained closed for four minutes. East<sub>65 </sub>The article was less stiff than the article in Example 1 above.
102 T3 26
Example 4
In vitro formation of an implant precursor with a glass substrate
Two spacers with approximate 430 pm thicknesses will be constructed by gluing two sets of three microscope glass slide covers. These were placed on a glass microscope slide with a space between them. Then approximately 0.3 g of the same polymer mixture as in Example 1 was dispensed onto the microscope slide between the spacers using a syringe. An atomizer was used to spray the polymeric mixture three times with water. After 30 seconds the spraying with water was repeated. After another 30 seconds, another microscope slide was sprayed with water and then pressed onto the coagulating polymeric mass and spacers. This second microscope slide was held in position for 60 seconds and then removed. The coagulating polymeric mass is then sprayed three times with water and allowed to set for 60 seconds. After the three sprays of water and the 60 seconds were repeated. The microscope glass slide and the coagulating polymeric mass were then placed on a 1 mm square rack. A sterile blade will then be used to cut the polymeric dough to the desired size and shape. The cut piece is then sprayed with water three times and allowed to set for 60 seconds. The excess water was then removed using a gauze pad. The opaque and flexible implant precursor was then ready for implantation.
Example 5
In vitro formation of an implant precursor with a glass substrate
A 5.08 x 7.62 cm (2x3 inch) microscope slide with a 20 mm x 20 mm graphic is placed on the underside on a Gray-Lite n dark background glass.<sup>or</sup> 14 x 5.08 x 7.72 x 0.63 cm (2 x 3 x 1/4 inches). 750 micron stainless steel washers of 2.54 cm (1 inch) diameter were placed on the upper side of the microscope slide. A washer is placed to the left and right of the inscribed graphic. A polymer mixture prepared as described in Example 1 was then layered onto the microscope slide and smoothed out to remove bubbles and uneven areas. Sterile isotonic saline will be carefully poured into the middle of the liquid polymeric layer where it will flow to the sides to cover the entire film. The saline was allowed to be in contact with the polymeric mixture for 1 minute, during which time the external surface or coating became opaque. The excess saline was then carefully removed by air or sponge spray and the entire process was repeated again with the addition of more polymeric mixture and saline to coagulate the polymer. After the second layer had set for 1 minute, a regular 2.54 x 7.62 cm (1 x 3-inch) glass microscope slide moistened with saline was placed on top of the polymeric mixture and compressed at the height of stainless steel washers (750 pm). Additional saline was added to the edge of the por14
ES 2 173 102 T3 regular microscope glass slides to saturate the underside of the slide. The compressed material was allowed to set for a further 10 minutes. The regular microscope slide and washers were then removed and the implant precursor film was cut with a single razor blade to the dimensions of the periodontal defect.
Example 6 Application of an implant precursor to a periodontal defect
The mandibular first molar of a 65-year-old man was selected for treatment because of the depth of a durable socket and the involvement of bifurcation. During surgery, a full thickness periodontal fin was elevated, the defect was scaled and the root flattened, and the dimensions of the defect were measured. A customized implant precursor barrier membrane prepared according to Example 5 was applied over the periodontal defect to approximate the level of the crown margin and cover the oyseal margins by 2 to 3 mm. The precursor material adhered directly to the tooth and bone without the need for suturing in place. The buccal flap was repositioned over the defect and implant precursor and sutured to the lingual tissue. A periodontal dressing material was applied to the surgical area and systematic antibiotic therapy was used for 7 days. After a week, the fully formed barrier was in position. At one month, the barrier was also present, but buccally displaced from the tooth surface due to the formation of granulation tissue between the barrier and the root surface. At the 6-month examination, the barrier was no longer evident and the epithelium had grown over the area of anterior granulation tissue. Clonal probe measurements then showed that the depth of the periodontal cavity had decreased from 5mm to 2mm and the level of tissue attachment to the tooth had increased from 7mm to 4mm. The horizontal bifurcation depth had also decreased from 5 mm to 3 mm. All clonal measurements indicated good tissue regeneration at the defect site.
Example 7
Treatment using an implant precursor in combination with a support layer
A polymeric mixture can be prepared as described in Example 1. A surgical incision can be made in a thigh bone of an anesthetized male mouse to create a defect. Surgicel ™ oxidized cellulose granules can be applied to the defect to stop bleeding and fill the defect. A precursor implant prepared as described in Example 1 can be applied to the surface of the Surgicel ™ support layer. The tissue is then repositioned and sutured in position. The implant precursor further solidified to a solid barrier matrix. Example 8
Treatment with an implant precursor including a biological agent
A polymeric mixture can be prepared as described in Example 1. To this mixture 5% by weight of doxycycline hyclate can be added. An implant article can then be prepared from the drug / primer mixture as described in Example 1. The implant article can be placed in a periodontal defect as described in Example 6. Doxycycline is dispensed from the solid barrier implant as it degrades and provides protection against bacterial infection.
Contents5
2 sheets
Sheet 1 Sheet 2
68 members in 17 offices
Priority claims5
| Document | Office | Kind | Date |
|---|---|---|---|
| 12764293 | United States of America | A | |
| 12764293 | United States of America | A | |
| 19930127642 | United States of America | – | |
| 94113193 | – | – | – |
| US19930127642 | – | – | – |
Members68
| Document | Office | Kind | |
|---|---|---|---|
| CA2063729A1 | Canada | A1 | |
| WO9101126A1 | World Intellectual Property Organization (WIPO) | A1 | |
| AU6071890A | Australia | A | |
| US5077049A | United States of America | A | |
| NO920302D0 | Norway | D0 | |
| FI920293A7 | Finland | A7 | |
| NO920302L | Norway | L | |
| EP0484387A1 | European Patent Office (EPO) | A1 | |
| AU2605492A | Australia | A | |
| CA2079831A1 | Canada | A1 | |
| EP0539751A1 | European Patent Office (EPO) | A1 | |
| KR930007464A | Republic of Korea | A | |
| JPH05504941A | Japan | A | |
| JPH05305135A | Japan | A | |
| EP0484387B1 | European Patent Office (EPO) | B1 | |
| AT100308T | Austria | T | |
| ATE100308T1 | Austria | T1 | |
| DE69006216D1 | Germany | D1 | |
| DK0484387T3 | Denmark | T3 | |
| DE69006216T2 | Germany | T2 | |
| US5324519A | United States of America | A | |
| AU653498B2 | Australia | B2 | |
| US5368859A | United States of America | A | |
| ES2062540T3 | Spain | T3 | |
| CA2117394A1 | Canada | A1 | |
| AU6614294A | Australia | A | |
| KR950007878A | Republic of Korea | A | |
| EP0649662A1 | European Patent Office (EPO) | A1 | |
| JPH07163654A | Japan | A | |
| US5487897A | United States of America | A | |
| AU666676B2 | Australia | B2 | |
| NZ244581A | New Zealand | A | |
| US5599552A | United States of America | A | |
| US5660849A | United States of America | A | |
| NZ286487A | New Zealand | A | |
| JP2685353B2 | Japan | B2 | |
| EP0539751B1 | European Patent Office (EPO) | B1 | |
| AT163261T | Austria | T | |
| ATE163261T1 | Austria | T1 | |
| DE69224456D1 | Germany | D1 | |
| DE69224456T2 | Germany | T2 | |
| ES2114901T3 | Spain | T3 | |
| HK1005426A1 | Hong Kong, China | A1 | |
| CA2063729C | Canada | C | |
| KR100248326B1 | Republic of Korea | B1 | |
| US6071530A | United States of America | A | |
| EP1147781A1 | European Patent Office (EPO) | A1 | |
| US2002001608A1 | United States of America | A1 | |
| EP0649662B1 | European Patent Office (EPO) | B1 | |
| AT212866T | Austria | T | |
| ATE212866T1 | Austria | T1 | |
| DE69429801D1 | Germany | D1 | |
| DK0649662T3 | Denmark | T3 | |
| US6395293B2 | United States of America | B2 | |
| SI0649662T1 | Slovenia | T1 | |
| DE69429801T2 | Germany | T2 | |
| PT649662E | Portugal | E | |
| ES2173102T3This record | Spain | T3 | |
| JP2003093498A | Japan | A | |
| JP3451259B2 | Japan | B2 | |
| EP1147781B1 | European Patent Office (EPO) | B1 | |
| AT268611T | Austria | T | |
| ATE268611T1 | Austria | T1 | |
| DE69433843D1 | Germany | D1 | |
| DK1147781T3 | Denmark | T3 | |
| ES2225364T3 | Spain | T3 | |
| DE69433843T2 | Germany | T2 | |
| CA2079831C | Canada | C |
1 legal event, as the office reported them to INPADOC
Events
| Event | Code | |
|---|---|---|
| Definitive protectionFG2A | FG2A |
Numbers
- Publication
- 2173102
- Publication, DOCDB
- 2173102
- Publication, EPODOC
- ES2173102T
- Application
- 94113193
- Application, DOCDB
- 94113193
- Application, EPODOC
- ES19940113193T
Titles2
- Spanish
- PRECURSOR DE IMPLANTE BIODEGRADABLE.
- English
- BIODEGRADABLE IMPLANT PRECURSOR.
Classification
- CPC, 27
- A61K9/0024
- A61L15/12
- A61K9/0063
- A61K9/1647
- A61K31/74
- A61K33/42
- A61K47/34
- A61L27/16
- A61L27/18
- A61L27/50
- A61L27/54
- A61L27/56
- A61L27/58
- A61L31/14
- A61L31/148
- A61L2300/404
- A61L2300/406
- A61L2300/41
- A61L2300/414
- A61L2300/416
- A61L2300/43
- A61L2300/602
- B29C41/08
- B29C41/12
- B29C67/06
- B29K2995/0056
- B29K2995/006
- IPC, 24
- A61C8 00
- A61C19 06
- A61F2 02
- A61F2 08
- A61F2 28
- A61K6 00
- A61K9 00
- A61K9 16
- A61K31 74
- A61K33 42
- A61K47 34
- A61L27 00
- A61L27 16
- A61L27 18
- A61L27 50
- A61L27 54
- A61L27 56
- A61L27 58
- A61L31 14
- B29C41 00
- B29C41 08
- B29C41 12
- B29C67 00
- B29C67 06