Stable composition comprising particles in a frozen aqueous matrix

IS 2 340 261 T3

DESCRIPTION

Stable composition comprising particles in a frozen aqueous matrix.

Background of the invention

Technical field

The present invention describes a composition of a stable suspension of a poorly soluble compound in water comprising particles of the compound suspended in a frozen aqueous matrix and the method for its preparation. The composition is stable for a long period of time, preferably six months or more.

Background of the technique

More and more poorly soluble or insoluble pharmaceutical compounds are being formulated in aqueous solutions. These compounds represent a challenge in terms of their administration in injectable form. Water insoluble drugs can have significant advantages when formulated as a stable suspension of submicron particles. Accurate particle size control is essential for the safety and effective use of these formulations. The particles must be less than seven microns in diameter to safely pass through capillaries without causing emboli (Allen et al., 1987; Davis and Taube, 1978; Schroeder et al., 1978; Yokel et al., 1981 ). One solution to this problem is the production of extremely small particles of the insoluble drug candidate and the creation of a microparticulate or nanoparticulate suspension. In this way, drugs that previously could not be formulated in a water-based system can be adequately obtained for intravenous administration. Suitably, for intravenous administration a small particle size (<7 pm), low toxicity (from toxic formulation components or residual solvents) and bioavailability of the drug particles are necessary after administration.

Suspensions may also be suitable for oral, intramuscular, pulmonary, topical, or subcutaneous administration. When administered by these routes, a particle size in the range of 5 to 100 microns may be desirable.

Suspensions may lack sufficient physical and chemical stability when stored for an extended period of time. Physical instability occurs when particles aggregate into larger particles, which is generally the result of a small particle size. Ostwald-Mie ripening can occur due to the small radius of the particles and the concomitant increase in surface activity, hence in solubility. In particular, nanoparticles have a very high surface: volume ratio, which improves their dissolution rate and solubility. As a consequence, the particles can be solubilized in the suspension, which is followed by recrystallization to form large crystals. Crystal aggregation and growth result in nanoparticle suspensions with a larger and variable particle size. Suspensions with particles greater than 7 pm are no longer suitable for intravenous administration.

In suspension, the active ingredient can also undergo degradation and, over time, result in reduced activity due to interaction with the suspending medium. A slight dissolution can even accelerate the degradation of the active ingredient. The rate of chemical degradation depends on the particle size, the intrinsic solubility and the chemical nature of the active ingredient.

It is highly desirable to have a pharmaceutical preparation of an aqueous suspension with a long shelf life, preferably at least six months, in terms of both physical and chemical stability.

Various methods have been described in the prior art to limit the aggregation and growth of suspended nanoparticle crystals to improve their physical stability as well as their shelf life. One method includes the step of adding surface stabilizers to the preparations. Suitable surface stabilizers include surfactants, polymers, cloud point modifiers (see U.S. Patent Nos. 5,298,262, 5,346,702, and 5,470,583), crystal growth modifiers (see U.S. Patent No. 5,665,331) and cryoprotectants (see US Patent No. 5,302,401). Although such approaches have been successful in limiting particle aggregation as well as crystal growth, surface active agents may not be found that would allow prolonged storage of the suspension in its liquid state, at room temperature or in the refrigerator. Or, if such stabilizing agents are found, they may have unsuitable toxicity profiles.

Another approach to inhibiting nanoparticle crystal growth and aggregation is to limit the mean particle size to a narrow range, from about 150 nm to about 350 nm, as described in Liversidge et al. United States No. 6,267,989. Patent No. 6,267,989 describes that crystal aggregation and growth are minimized when the particles are in this size range. However, the narrow range of the particle size limits its applications. For some applications, it may be desirable to have nanoparticle suspensions with a particle size greater than 400 nm. These applications include, but are not limited to, oral, subcutaneous, or intramuscular administration, where the convenient particle size can be from 5 to 100 microns. In other formulations, the particle size

Convenient ES 2 340 261 T3 may be less than 100 nm. This is evidenced, for example, in particles designed to bypass the RES (reticuloendothelial system). These long-circulating particles can also migrate through the loose, fenestrated vasculature, such as that associated with certain cancerous tumors. This would facilitate the passive targeting of these tumors.

Yiv et al. describe, in US Patent No. 6,245,349, a stable lipid nanoparticle formulation of lipophilic and amphipathic drugs. The formulation is an oil-in-water microemulsion that is composed of phospholipids, propylene glycol, polyethylene glycol, a surfactant, and water. An oil component such as a triglyceride is optional. The components are mixed together to form an emulsion. The mean particle size must be less than 200 µm for the preparation, which must be sterilized by filtration. The composition can be stored in concentrated form or in diluted form. The diluted form includes an aqueous buffer and is stable in a temperature range of about -50 ° C to about 40 ° C. In Example 1, the composition was stored at -20 ° C for 21 days with no evidence of phase separation, change in particle size, or crystallization of the drug. The method, however, is limited to oil-in-water dispersions with a particle size less than 200 nm in which all components are liquid. These dispersions are generally sterilized by filter sterilization, requiring the dispersion to pass through filters with a pore size of 220 nm.

The prior art also describes methods for improving the chemical stability of nanoparticle preparations during prolonged storage. The general approach is to remove the aqueous medium by lyophilization and store the nanoparticles in a dry, lyophilized form. An example is described in Example 6 of US Patent No. 5,091,187. In general, dialysis is required prior to lyophilization to remove any unwanted solutes, such as a salt, or to prevent concentration of such solutes during the lyophilization process. The additional steps of dialysis and lyophilization increase production costs, as dialysis is a time-consuming process and lyophilization is an energy-consuming process. Furthermore, the lyophilized preparation requires reconstitution with an appropriate dispersing medium before administration by injection (intravenously, intramuscularly or subcutaneously) or orally. This requires more work in administering the pharmaceutical agent, as well as the potential for human error that can occur during reconstitution.

As part of the effort to develop new methods for stabilizing these suspensions, we have discovered that freezing can circumvent these instability mechanisms by coating the drug particles with a frozen aqueous matrix. At temperatures as low as these, the solubility of the drug is reduced and the very high viscosity of the aqueous medium discourages the diffusion of the dissolved drug out of the solid particle. This includes nucleation, crystal growth, and Ostwald ripening. Lower temperatures also increase chemical stability by slowing down the degradation of the drug in the aqueous medium. Crystallization of water can also take place, for example below the eutectic point of the mixture, thus eliminating the possibility of forming a phase in solution containing the drug, which can undergo secondary nucleation, crystal growth and maturation. of Ostwald.

The nanoparticles of the invention can be prepared by any method known in the art. One approach focuses on reducing the size of the particles that deliver the drug. In a series of patents including US Patent Nos. 6,228,399, 6,086,376, 5,922,355, and 5,660,858, Parikh et al. Disclose that sonication can be used to prepare microparticles of an insoluble compound. in water. Among these patents, US Patent No. 5,922,355 describes an improvement to a method that employs sonication to make smaller particles. The improvement comprises mixing an active pharmacological agent with a phospholipid and with surfactants in a single phase aqueous system and applying energy to the system to produce smaller particles. However, stabilization of the suspension by freezing is not mentioned.

US Patent No. 5,091,188, issued by Haynes, also describes reducing the particle size of a pharmacologically active water-insoluble drug and employing a lipid coating on the particles to produce a solid form. The patent is directed to a pharmaceutical composition consisting essentially of an aqueous suspension of solid drug particles with a diameter of from about 0.05 to about 10 microns. The lipid coating attached to the surface of the particles acts to stabilize them. The composition is produced by adding the drug to water in the presence of membrane-forming lipid surfactants and then reducing the particle size within the aqueous suspension. However, freezing of the suspension is not cited as a stabilization method.

US Patent No. 5,858,410 describes a pharmaceutical nanosuspension suitable for parenteral administration. Patent No. 5,858,410 indicates that subjecting at least one solid therapeutically active compound dispersed in a solvent to high pressure homogenization in an interval piston homogenizer to form particles with a mean diameter, determined by photon correlation spectroscopy (PCS), 10 nm to 1,000 nm, the proportion of particles larger than 5 microns in the total population is less than 0.1% (particle number distribution determined with a Coulter counter), without prior conversion to a melt, where the active compound is solid at room temperature and it is insoluble, only slightly soluble or moderately soluble in water, aqueous media and / or organic solvents. Examples of Patent No. 5,858,410 mention jet milling prior to homogenization.

IS 2 340 261 T3

US Patent No. 5,145,684 describes another approach for providing insoluble drug nanoparticles for parenteral delivery by reducing particle size. Patent No. 5,145,684 describes the wet milling of an insoluble drug in the presence of a surface modifier to provide drug particles with an effective average particle size of less than 400 nm. Patent No. 5,145,684 emphasizes the convenience of not using solvents in its process. Patent No. 5,145,684 indicates that the surface modifier is adsorbed on the surface of the drug particle in an amount sufficient to prevent agglomeration into larger particles.

In addition to physically reducing the particle size of the drug and coating the particles with a surface stabilizer, nanoparticles can also be prepared by various precipitation methods. These methods typically involve dissolving the drug in a solvent as a continuous phase, which is followed by changing the conditions of the solution in a non-continuous phase so that the fine particles are precipitated out in the non-continuous phase. Typically a coating agent or surface stabilizer is used to co-precipitate with the drug in order to stabilize the particles. Examples of these precipitation methods are solvent and antisolvent microprecipitation, phase inversion precipitation, pH change precipitation, supercritical fluid precipitation, and temperature change precipitation.

Examples of suitable precipitation techniques include the preparation of nanoparticle suspensions as described in US Patent Application Serial No. 60 / 258,160; 09 / 874,799; 09 / 874,637; 09 / 874,499 and 09 / 953,979. These applications describe the formation of small particles of organic compounds by dissolving the organic compound in a water-miscible organic solvent, followed by precipitation of the organic compounds in an aqueous medium to form a pre-suspension, followed by the addition of energy to the pre-suspension. to stabilize a coating of the particle, to modify the lattice structure of the particle or to reduce the particle size. Preferably the process is used to prepare a suspension of a poorly water soluble pharmaceutically active compound.

US Patent No. 5,118,528 describes a process for preparing nanoparticles by precipitation with solvents and antisolvents. The process includes the steps of (1) preparing a liquid phase of a substance in a solvent or in a mixture of solvents to which one or more surfactants can be added, (2) preparing a second liquid phase of a non-solvent or of a mixture of non-solvents, the non-solvent being miscible with the solvent or the mixture of solvents for the substance, (3) add solutions (1) and (2) together with stirring; and (4) removing unwanted solvents to produce a colloidal suspension of nanoparticles. Patent No. 5,118,528 indicates that substance particles smaller than 500 nm are produced without supplying energy. In particular, the patent 5,118,528 establishes that it is not advisable to use high energy equipment, such as sonicators and homogenizers.

US Patent No. 4,826,689 describes a method of making uniform-sized particles from water-insoluble drugs or other organic compounds. First, a suitable solid organic compound is dissolved in an organic solvent, and the solution can be diluted with a non-solvent. Next, an aqueous precipitation liquid is infused, which precipitates the non-aggregated particles with a substantially uniform mean diameter. The particles are then separated from the organic solvent. Depending on the organic compound and the desired particle size, the parameters of temperature, ratio between non-solvent and organic solvent, infusion rate, stirring rate and volume can change according to the invention. Patent No. 4,826,689 describes that in this process a drug is formed in a metastable state that is thermodynamically unstable. Patent No. 4,826,689 indicates the capture of the drug in a metastable state by using crystallization inhibitors (for example polyvinylpyrrolidinone) and surface active agents (for example polyoxyethylene) -co (oxypropylene) to convert the metastable precipitate into Stable enough to be isolated by centrifugation, membrane filtration or reverse osmosis.

US Patent No. 5,780,062 describes a method for preparing small particles of insoluble drugs by (1) dissolving the drug in a first water-miscible solvent, (2) preparing a second solution of a polymer and an amphiphile in a second aqueous solvent, the drug being substantially insoluble, whereby a polymer / amphiphilic complex is formed and (3) mixing the solutions of the first and second stages to precipitate an aggregate of the drug and the polymer / amphiphilic complex.

US Patent No. 4,997,454 describes a method for making uniform size particles from solid compounds. The method of patent No. 4,997,454 includes the steps of dissolving the solid compound in a suitable solvent, followed by infusion of the precipitation liquid, thus precipitating non-aggregated particles with a substantially uniform mean diameter. Then the solvent particles are separated. Patent No. 4,997,454 does not promote the formation of crystalline particles because, during the precipitation process, the crystals can dissolve and recrystallize, thus broadening the range of particle size distribution. Patent No. 4,997,454 favors the capture of the particles in a thermodynamically unstable state during the precipitation process.

US Patent Nos. 6,235,224 B1 and 6,143,211, both published by Mathiowitz et al., Describe the use of phase inversion phenomena to precipitate microencapsulated microparticles. The method includes mixing a polymer and a drug with a solvent. This mixture is introduced into an effective amount of a miscible non-solvent, thus causing the spontaneous formation of the microencapsulated product.

IS 2 340 261 T3

Microprecipitation by pH change is another technology used to prepare dispersions of a nanoparticulate pharmaceutical agent. See for example US Patent Nos. 5,766,635; 5,716,642; 5,665,331; 5,662,883; 5,560,932; and 4,608,278. This technology involves dissolving a pharmaceutical compound in an aqueous base having a non-neutral pH, which is then neutralized to precipitate the compound in the aqueous base.

In still another approach, such as that described in US Patent No. 5,766,635, published by Spenlenhauer et al., Nanoparticles are prepared by dissolving a poly (ethylene oxide) and / or a copolymer of poly (propylene) oxide / polylactide in an organic solvent, mixing the organic solution thus formed with an aqueous solution so that the nanoparticles are separated by precipitation from the solution, and microfluidization of the suspension without the use of surfactants. In this way, support particles are formed, which are composed of a solid polymeric matrix, in which a co-precipitated pharmaceutical agent can be incorporated.

Supercritical fluid precipitation is described in US Patent Nos. 5,360,478 and 5,389,263 to Krukonis et al., As well as WO 97/14407 to Johnston. The technology is similar to the solvent and antisolvent precipitation method. In this case, the supercritical fluid, which can be a gas or a liquid under conditions of pressure and temperature above its critical point, acts as an antisolvent. The addition of the supercritical fluid to a solution of a solute in a solvent causes the solute to reach or approach the supersaturated state and to precipitate out into fine particles.

Temperature change precipitation is described in US Patent No. 5,188,837 to Domb. The method involves the addition of a thermally stable drug to a polymer. The polymer is often based on an oil (eg phospholipids, synthetic waxes) and has a low melting point. The drug is heated with the polymer to a point slightly above the melting point of the polymer, to form a hot emulsion of the drug in the molten polymer. The emulsion is then rapidly cooled by adding the emulsion to a cold non-solvent bath, such as water, with vigorous stirring, so that the emulsion drops and solidifies, capturing the active agent in the suspension.

Still another approach to preparing submicron particles of poorly water soluble organic compounds is to form an emulsion of the compound. The organic compound dissolves in an organic phase. The organic phase forms an emulsion with an aqueous phase. An emulsion-evaporation method is described in US Patent Application Serial No. 09 / 964,273. The method includes the steps of: (1) providing a multiphase system having an organic phase and an aqueous phase, the organic phase including a pharmaceutically effective compound; and (2) sonicating the system to evaporate a part of the organic phase, so that the compound is precipitated in the aqueous phase and with an effective average particle size less than about 400 nm.

US Patent No. 5,605,785 describes a process for forming nanoamorphic dispersions of photographically useful compounds. The nanoamorphic dispersion formation process includes any known emulsification process that produces a dispersed phase with amorphous particulates.

Still another approach to preparing a submicron-sized nanoparticle suspension of a pharmaceutically active compound consists of seeding, at some point during a precipitation process, to generate crystals of a desired morphology (see U.S. Patent Application No. Serial No. 10 / 035.821). The method comprises the steps of dissolving a first amount of the pharmaceutically active compound in the first water-miscible organic solvent to form a first solution. Then the first solution is sown. Alternatively, a second solvent can be seeded. It is also possible to use seed compounds at other points during the precipitation process. The first solution is then mixed with the second solvent. Mixing of the first solution with the second solvent results in the precipitation of the pharmaceutically active compound in the desired morphological form.

Another approach is directed at the production of protein-coated suspended particles. US Patent No. 5,916,596 issued by Desai et al. describes the application of high shear stress to a mixture of an organic phase containing a pharmacologically active agent and an aqueous medium containing a biocompatible polymer. The mixture is subjected to shear stress in a high pressure homogenizer, at a pressure in the range of about 3,000 to 30,000 psi. Patent No. 5,916,596 requires that the mixture contain substantially no surfactant, since the combined use of a surfactant with a protein results in the formation of large, needle-like crystalline particles, the size of which increases during storage. See columns 17-18 in Example 4.

US Patent No. 5,560,933, published by Soon-Shiong et al., Describes the formation of a polymeric shell around the water-insoluble drug for delivery in vivo. The method describes the application of sonication to a mixture comprising an aqueous medium containing a polymer and a dispersing agent with a substantially water-insoluble drug dispersed therein. In this reference, sonication is used to effect the formation of disulfide bonds in the polymer, causing the polymer to crosslink, producing a polymeric envelope around the drug. Sonication is carried out for a time sufficient for disulfide bonds to form.

In US Patent No. 5,665,383, Grinstaff et al. describe the application of ultrasound to a single B phase, i.e. an aqueous medium, to encapsulate an immunostimulating agent in a polymeric envelope for its

ES 2 340 261 T3 delivered in vivo. Ultrasound favors the crosslinking of the encapsulating agent by the disulfide bonds to form the shell.

US Patent Nos. 5,981,719 and 6,268,053 describe a method for preparing microparticles of macromolecules with a particle size of less than 10 microns. The macromolecules are mixed with a soluble polymer or with a mixture of soluble polymers (for example albumin) at a pH close to the isoelectric point of the macromolecule in the presence of energy, preferably heat, for a predetermined period of time. The microparticles formed by this process allow aqueous fluids to penetrate and solubilized macromolecules and polymers to exit the microparticles and can be processed to exhibit short-term or long-term release kinetics, thus providing rapid or sustained release of the particles. macromolecules.

Summary of the invention

One of the drawbacks of aqueous nanoparticle suspensions is their poor physical and chemical stability. Physical instability is due to particle aggregation and crystal growth. Chemical instability is due to degradation of the solubilized active ingredient in the surrounding solution that is in equilibrium with the suspended solid phase, which can be enhanced due to interactions of the active ingredient with excipients such as surfactants and buffers. Due to these stability problems, many aqueous nanoparticle systems are not suitable for use as pharmaceutical preparations. For example, when the dissolved active compound is chemically unstable due to hydrolysis, for example, then decomposition in solution would shift the chemical balance towards progressive degradation and loss of the active ingredient.

We have found that freezing can avoid these instability mechanisms by wrapping drug particles in a frozen aqueous matrix. At temperatures as low as these, the solubility of the drug is reduced and the very high viscosity of the aqueous medium discourages the diffusion of the dissolved drug out of the solid particle. This includes nucleation, crystal growth, and Ostwald ripening. Lower temperatures also slow down the spontaneous degradation of drug molecules in the aqueous medium, improving their chemical stability. Low temperatures also slow down the degradation of the active ingredient due to its interactions with excipients. Crystallization of the water can also take place, for example below the eutectic point of the mixture, thus eliminating the possibility of forming a solution phase containing the drug and may undergo secondary nucleation, crystal growth and Ostwald ripening.

The present invention provides a composition of a stable suspension of nanoparticles of a poorly water soluble organic pharmaceutical agent in an aqueous matrix according to claim 1, as well as a method for preparing the composition according to claim 23. It is also described the supply of a stable suspension of other compounds such as cosmetic products, photographic agents and the like. The composition can be stored for an extended period of time, preferably six months or more.

The invention can be applied to any nanoparticle system known in the art. Nanoparticle suspensions can be prepared from any of the known methods, such as physical milling, homogenization, high shear mixing, emulsion-evaporation precipitation, solvent and antisolvent precipitation, supercritical fluid precipitation, exchange precipitation of temperature, precipitation by change of pH, precipitation by melting and seeding.

The invention is also applicable to nanoparticle systems with a wide range of compositions including, for example, surface modifiers, pH adjusting agents, crystal growth modifiers, cryoprotective agents, osmotic agents, co-solvents and viscosity modulating agents.

The composition does not require any reconstitution with an appropriate dispersing agent prior to use and is applicable to a variety of routes of administration, including, but not limited to, injection (intravenous, intramuscular, subcutaneous), pulmonary, ophthalmic, topical, and oral.

These and other aspects and attributes of the present invention are set forth with reference to the following figures and accompanying specification.

Detailed description of the invention

Although this invention is capable of many different embodiments, the preferred embodiments of the invention are described in detail herein, these being considered as examples of the principles of the invention and not intended to limit the broad aspects of the invention to the illustrated embodiments.

The present invention describes a pharmaceutical composition for intravenous or oral administration, as well as a method for preparing the composition as a suspension of nanoparticles in an aqueous matrix. Parenteral administration includes intravenous, intraarterial, intrathecal, intraperitoneal, intraocular, intraarticular, intradural, intramuscular, intradermal, or subcutaneous injection. The composition is also suitable for other non-oral routes of administration, including for example topical, ophthalmic, nasal, buccal, inhalation, rectal, and the like.

IS 2 340 261 T3

The pharmaceutical agent is a compound that is poorly soluble in water. The composition is physically and chemically unstable when stored in the refrigerator or at room temperature for an extended period of time, preferably for a year or more. Stabilization can be achieved by freezing the aqueous suspension of nanoparticles and storing the composition in its frozen state. At temperatures as low as these, the solubility of the drug is reduced and the very high viscosity of the aqueous medium discourages the diffusion of a dissolved drug out of the solid particle containing the drug. This includes nucleation, crystal growth, and Ostwald ripening. Lower temperatures also slow the spontaneous degradation of drug molecules in the aqueous medium to improve their chemical stability. Crystallization of water can also take place, for example below the eutectic point of the mixture, thus eliminating the possibility of forming a phase in solution containing the drug, which can undergo secondary nucleation, crystal growth and Ostwald ripening. .

Suspensions of other poorly water soluble materials that are not pharmaceutical agents are also described, including, for example, compounds for photographic use.

A. Compositions of nanoparticle suspensions

The composition of the invention comprises nanoparticles of a pharmaceutical agent suspended in a frozen aqueous matrix as defined in claim 1. As desired, one or more other excipients may be included in the composition, depending on the particular pharmaceutical agent, the method. to prepare the nanoparticle suspension and the route of administration.

1. Pharmaceutical Agents

The invention can be practiced with a wide variety of poorly water soluble organic pharmaceutical agents which can be therapeutic agents, diagnostic agents or cosmetic products.

The pharmaceutical agent can be in a crystalline phase or in an amorphous, non-crystalline phase. The agent is preferably poorly soluble in water. By "poorly soluble in water" it is meant that the pharmaceutical agent has a solubility in water of less than 10 mg / ml, and preferably less than 1 mg / ml. These agents poorly soluble in water are the most suitable for preparations of aqueous suspensions of nanoparticles, since there are limited alternatives to formulate these agents in aqueous medium. Other water soluble pharmaceutical agents exist by entrapment in a solid support matrix (eg polyacetate-polyglycolate copolymer, albumin, starch), or by encapsulating these agents in a surrounding vesicle that is impermeable to the pharmaceutical agent. This encapsulating vesicle can be a polymeric coating such as polyacrylate. Furthermore, nanoparticles and microparticles prepared from these water soluble pharmaceutical agents can be modified to improve chemical stability and control the pharmacokinetic properties of the agents by controlling the release of the agents from the particles. Examples of water soluble pharmaceutical agents include, but are not limited to, simple organic compounds, proteins, peptides, nucleotides, oligonucleotides, and carbohydrates.

The therapeutic agent can be selected from a variety of known classes of pharmaceuticals, including, for example, analgesics, anti-inflammatory agents, anthelmintics, antiarrhythmic agents, antibiotics (including penicillins), anticoagulants, antidepressants, antidiabetic agents, antiepileptics, antifungals, antihistamines, antihypertensive agents, antimuscarinic agents, antimycobacterial agents, antineoplastic agents, antiprotozoal agents, immunosuppressants, immunostimulants, antithyroid agents, antiviral agents; anxiolytic sedatives (hypnotics and neuroleptics), astringents, beta-adrenoceptor blocking agents, blood products and substitutes, cardiac inotropic agents, contrast media, corticosteroids, antitussives (expectorants and mucolytics), diagnostic agents, diagnostic imaging agents , diuretics, dopaminergics (antiparkinsonian agents), hemostats, immunological agents, lipid regulating agents, muscle relaxants, parasympathomimetics, parathyroid calcitonin as well as bisphosphonates, prostaglandins, radiopharmaceuticals, sex hormones (including steroids), antiallergic, stimulant and anoretic agents, sympathomimetics, thyroid agents, vasodilators, vaccines and xanthines.

Diagnostic agents include X-ray imaging agents and contrast media. Examples of X-ray imaging agents include WIN-8883 (ethyl 3,5-diacetamido-2,4,6-triiodobenzoate), also known as diatrizoic acid ethyl ester (EEDA), WIN-67722, that is Ethyl 6-ethoxy-6-oxohexyl-3,5-bis (acetamido) -2,4,6-triiodobenzoate; Ethyl 2- (3,5-bis (acetamido) -2,4,6-triiodobenzoyloxy) butyrate (WIN 16318); ethyl diatrizoxyacetate (WIN 12901); Ethyl 2- (3,5-bis (acetamido) -2,4,6-triiodobenzoyloxy) propionate (WIN 16923); N-ethyl-2- (3,5-bis (acetamido) -2,4,6-triiodobenzoyloxy) acetamide (WIN 65312); isopropyl-2- (3,5bis (acetamido) -2,4,6-triiodobenzoyloxy) acetamide (WIN 12855); Diethyl 2- (3,5-bis (acetamido) -2,4,6-triiodobenzoyloxy) malonate (WIN 67721); Ethyl 2- (3,5-bis (acetamido) -2,4,6-triiodobenzoyloxy) phenylacetate (WIN 67585); Propanedioic acid, [[3,5-bis (acetylamino) -2,4,5-triiodobenzoyl] oxy] bis (1-methyl) ester (WIN 68165); and benzoic acid, 3,5-bis (acetylamino) -2,4,6-triiodo-4- (ethyl-3-ethoxy-2-butenoate) ester (WIN 68209). Preferred contrast agents include those that are expected to disintegrate relatively quickly under physiological conditions, thus minimizing any inflammatory response associated with the particles. Disintegration can result from enzymatic hydrolysis, solubilization of carboxylic acids at physiological pH, or other mechanisms. Therefore, the poorly soluble iodinated carboxylic acids, such as iodipamide, diatrizoic acid and metrizoic acid, together with the species

ES 2 340 261 T3 hydrolytically labile iodides, such as WIN 67721, WIN 12901, WIN 68165 and WIN 68209, or others may be preferred.

Antineoplastic or anticancer agents include, but are not limited to, paclitaxel and derivative compounds and other antineoplastic agents selected from the group consisting of alkaloids, antimetabolites, alkylating agents, and antibiotics.

Preferred diagnostic or therapeutic agents include those intended for oral administration and intravenous administration. A description of these classes of therapeutic and diagnostic agents, as well as a list of the species within each class, can be found in Martindale, The Extra Pharmacopoeia, Twentyninth Edition, The Pharmaceutical Press, London, 1989. Therapeutic agents and diagnostic agents are commercial and / or can be prepared by techniques known in the art.

A cosmetic agent is any active ingredient capable of having cosmetic activity. Examples of these active ingredients can be, among others, emollients, humectants, free radical inhibiting agents, anti-inflammatories, vitamins, depigmenting agents, anti-acne agents, anti-seborrheic agents, keratolytics, slimming agents, skin coloring agents and photoprotective agents, and, in particular, linoleic acid, retinol, retinoic acid, alkyl esters of ascorbic acid, polyunsaturated fatty acids, nicotinic esters, tocopherol nicotinate, unsaponifiables from rice, soy or shea (shea), ceramides, hydroxy acids such as glycolic acid, selenium derivatives, antioxidants, beta-carotene, gamma-onzanol and stearyl glycerate. Cosmetic products are commercial and / or can be prepared by techniques known in the art.

The pharmaceutical agent may be present in an amount of from about 0.01% to about 50%, in particular from about 0.1% to about 30%, and especially preferably from about 0.5% to about 5%, by weight of the composition.

2. Excipients

The other excipients in the invention are optional. One or more other excipients can be included in the composition. Examples of other excipients include buffers, pH adjusting agents, crystal growth modifiers, cryoprotectants, osmotic agents, co-solvents, and viscosity modulating agents.

The two or more surface modifiers that are included in the compositions of the invention are selected from among anionic surfactants, cationic surfactants, nonionic surfactants or surface active biological molecules as defined in claim 1.

Suitable anionic surfactants include, but are not limited to, potassium laurate, sodium lauryl sulfate, sodium dodecyl sulfate, alkyl polyoxyethylene sulfates, sodium alginate, dioctyl sodium sulfosuccinate, glyceryl esters, sodium carboxymethylcellulose, cholic acid and other bile acids (eg cholic acid, deoxycholic acid, glycocholic acid, taurocholic acid, glycodeoxycholic acid) and salts thereof (eg sodium deoxycholate, etc.). Suitable cationic surfactants include, but are not limited to, quaternary ammonium compounds such as benzalkonium chloride, cetyltrimethylammonium bromide, lauryldimethylbenzylammonium chloride, acylcarnitine hydrochlorides, or alkylpyridinium halides.

Suitable nonionic surfactants include polyoxyethylene fatty alcohol ethers (Macrogol and Brij), polyoxyethylene sorbitan fatty acid esters (Polysorbate s), polyoxyethylene fatty acid esters (Myri), polyoxyethylene or phospholipid derivatized lipids (Sorbitan esters, Span ), glycerol monostearate, polyethylene glycols, polypropylene glycols, cetyl alcohol, cetostearyl alcohol, stearyl alcohol, aryl alkyl polyether alcohols, Polyoxyethylene-polyoxypropylene copolymers (poloxamers), polaxamines, methylcellulose, hydroxycellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, non-crystalline cellulose, polysaccharides including starch and starch derivatives such as hydroxyethyl starch (HES), polyvinyl alcohol and solid alcohol. In a preferred form of the invention, the nonionic surfactant is a copolymer of polyoxyethylene and polyoxypropylene and preferably a block copolymer of propylene glycol and ethylene glycol. These polymers are sold under the trademark POLOXAMER, also sometimes referred to as PLURONIC.^®, and is sold by various suppliers, including Spectrum Chemical and Ruger. Polyoxyethylene fatty acid esters include those of the short alkyl chain. An example of such a surfactant is SOLIITOL® HS 15, polyethylene-660-hydroxystearate, manufactured by BASF Aktiengesellschaft.

Biological surface active molecules are selected from albumin, casein, heparin, hirudin, or other appropriate proteins.

Other representative examples of surface modifiers include gelatin, casein, gum acacia, cholesterol, tragacanth, stearic acid, benzalkonium chloride, calcium stearate, glycerol monostearate, cetostearyl alcohol, cetomacrogol emulsifying wax, sorbitan esters, polyoxyethylene alkyl ethers, for example macrogol ethers such as ketomacrogol 1000, polyoxyethylene castor oil derivatives, polyoxyethylene sorbitan fatty acid esters, for example commercial Tweens ™, polyethylene glycols, polyoxyethylene stearates, colloidal silicon dioxide, phosphates, sodium dodecyl sulfate, calcium carboxymethyl cellulose, sodium carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl cellulose, hydroxypropyl cellulose, hydroxypropyl cellulose, aluminum cellulosephthalate noxypropyl triethanolamine, polyvinyl alcohol and polyvinylpyrrolidone (PVP). Most of these super modifiers

Official ES 2 340 261 T3 are known pharmaceutical excipients and are described in detail in the Handbook of Pharmaceutical Excipients, jointly published by the American Pharmaceutical Association and the Pharmaceutical Society of Great Britain, the Pharmaceutical Press, 1986.

Surface modifiers are commercially available and / or can be prepared by techniques known in the art. Two or more surface modifiers are used in combination.

Suitable pH adjusting agents include, but are not limited to, buffers, sodium hydroxide, hydrochloric acid, tris (hydroxymethyl) aminomethane (tris), citrate, acetate, lactate, meglumine, or the like. Buffers also include, but are not limited to, amino acids such as glycine, leucine, alanine, lysine, or the like.

Suitable crystal growth modifiers are described in US Patent No. 5,665,331. A crystal growth modifier is defined as a compound that, in the co-precipitation process, is incorporated into the structure of the micro-precipitated crystals of the pharmaceutical agent, thus hindering the growth or enlargement of the microcrystalline precipitate by the so-called Ostwald ripening process. Some crystal growth modifiers can be structurally similar, on a molecular basis, to the pharmaceutical agent. Polymers are also suitable crystal modifiers, for example the crystallization inhibitor polyvinylpyrrolidinone, as described in US Patent No. 4,826,689. Crystal growth modifiers can also act by forming a complex with the solute, that is, by supersaturation, thus preventing or inhibiting nucleation and / or growth of the crystals.

Cryoprotectants for use in nanoparticle suspensions are described in US Patent No. 5,302,401. In said patent, cryoprotectants inhibit nanoparticle agglomeration during the lyophilization process. Examples of suitable cryoprotectants include carbohydrates such as sucrose, xylose, glucose, and sugar alcohols such as mannitol and sorbitol, surface active agents such as polysorbates (Tweens), as well as glycerol and dimethylsulfoxide. Cryoprotectants can also include water-soluble polymers such as polyvinylpyrrolidinone (PVP), starch, and polyalkoxy ethers such as polyethylene glycols, polypropylene glycols, and poloxamers. Biologically derived cryoprotectants include albumin. Still another class of cryoprotectants includes PEG lipids such as Solutol. A cryoprotectant is a carbohydrate. A preferred carbohydrate is a monosaccharide or a disaccharide. A preferred disaccharide is sucrose. Another preferred cryoprotectant includes, but is not limited to, polymers such as those listed above. Still another preferred cryoprotectant is albumin.

Viscosity modulating agents are agents that affect the viscosity of the composition. Examples of modulating agents are carbohydrates (eg celluloses, gums, sugars, sugar alcohols), polymers (eg poloxamers, poloxamines, polyvinylpyrrolidone), proteins (eg albumin, milk proteins). These agents are listed in the Handbook of Pharmaceutical Additives published by Gower, in the Thickeners Section, Viscosity control agents, Consistency regulators, Bodying agents, Antigellants, which is incorporated herein by reference and forms part of the same.

Suitable osmotic agents include sugars (eg dextrose, sucrose), sugar alcohols (eg mannitol, sorbitol), salts (eg sodium chloride), glycerol and glycerol derivatives, and the like.

Examples of suitable co-solvents are ethyl alcohol, dimethyl sulfoxide, and N-methyl-2-pyrrolidinone (also called N-methyl-2-pyrrolidone). Other examples include lactic acid, acetic acid, and other liquid carboxylic acids.

The excipient may be present in an amount of from about 0.001% to about 20%, preferably from about 0.01% to about 5%, by weight of the composition.

The excipient (s) may be added to the aqueous medium in the nanoparticle preparation process or they may be added directly to the pharmaceutical agent before mixing with the aqueous medium. If the pharmaceutical agent is dissolved in an organic phase prior to mixing with an aqueous antisolvent, the excipient (s) can be added to the organic phase prior to precipitation.

3. Particle Size and Shape of Nanoparticles

In this invention, particle size is measured by dynamic light scattering methods (e.g. photocorrelation spectroscopy, laser diffraction, low angle laser light scattering (LALLS), half angle laser light scattering (MALLS), light obscuration methods (Coulter method, for example), rheology or microscopy (light or electron) within the ranges stated above). The invention is applicable to suspensions of nanoparticles and microparticles of a wide range of particle size. The preferred effective mean particle size of the particles is less than about 2 pm, particularly less than about 400 nm and especially less than 200 nm or any range or combination of ranges.

Four. Methods of Preparation of Nanoparticle Suspensions

Aqueous suspensions of nanoparticles of the pharmaceutical agent can be prepared by any method, including mechanical grinding of the active agent, by precipitation techniques, or by methods

ES 2 340 261 T3 suspension of the pharmaceutical agent. Mechanical milling includes techniques such as jet milling, bead milling, ball milling, hammer milling, fluid power milling, or wet milling as described in US Patent No. 5,145,684.

A precipitation step can be applied to make a particle suspension, which is then subjected to an energy addition step. The energy addition step includes subjecting the particle dispersion to high shear stress conditions, including cavitation, shear, or impact forces, by means of a microfluidizer, interval piston homogenizer, or a countercurrent homogenizer, the conditions are describe in US Patent No. 5,091,188. Suitable range piston homogenizers are commercial, for example those sold by Avestin under the trademark EMULSIFLEX, and French Pressure Cells, sold by Spectronic Instruments. Microfluidics Corp., has suitable microfluidizers. The crystal seeding stage described below can be carried out at any point during the process consisting of subjecting the solution to high shear conditions and in particular it is carried out before the energy addition stage.

The energy addition step can also be carried out by sonication techniques. The sonication step can be performed with any suitable sonication device, such as the Branson Model S-450A or the Cole-Parmer Model 500-700 Watt. Such devices are well known in the industry. Typically, the sonication device has a sonication hom or probe that is inserted into the solution containing the drug to emit sonic energy into the solution. In a preferred form of the invention, the sonication device operates at a frequency from about 1 kHz to about 90 kHz and in particular from about 20 kHz to about 40 kHz or in any range or combination of ranges. Probe sizes can vary and are preferably in different sizes, such as * / 2 inch (1.3 cm) or * 4 inch (0.6 cm) or the like. It may also be convenient to cool the solution during sonication to temperatures below room temperature. The crystal seeding step described below can be carried out at any point during the process that consists of subjecting the solution to high shear conditions and, in particular, is carried out before the addition step.

5. Precipitation method

In the precipitation method, the pharmaceutical agent is dissolved in a solvent to establish a solution. The solution is then mixed with an aqueous medium to obtain a fine particle pre-suspension of the pharmaceutical agent. The aqueous medium may optionally contain one or more other excipients selected from the group of pH adjusting agents, cryoprotectants, crystal growth modifiers, osmotic agents, co-solvents, and viscosity modifiers. Excipients can also be included in the solvent in which the pharmaceutical agent is dissolved prior to the precipitation step. Pre-suspension energy can be applied as needed to stabilize the agent coating, to change the lattice structure, or to further reduce the particle size of the precipitate. Power sources include, but are not limited to, sonication, homogenization, microfluidization, countercurrent homogenization, or other methods that provide impact, shear, or cavitation forces. Power sources also include methods of providing continuous thermal input in the form of heating or cooling, or by varying temperature (eg, cycling).

Some known precipitation processes are emulsion-evaporation precipitation, microprecipitation, solvent and antisolvent precipitation, supercritical fluid precipitation, temperature change precipitation, pH change precipitation, and seeding.

Precipitation by emulsion-evaporation

The emulsion-evaporation method is described in US Patent Application Serial No. 09 / 964,273. The process comprises the steps of: (1) providing a multiphase system with an organic phase and an aqueous phase, the organic phase containing a pharmaceutically effective compound; and (2) sonicating the system so that a part of the organic phase evaporates, causing the compound to precipitate in the aqueous phase and with an effective mean particle size less than about 2 pm. The step of providing a multiphase system includes the steps of: (1) mixing a water-immiscible solvent (oil phase) with the pharmaceutically effective compound to define an organic solution, (2) preparing a water-based solution with one or more surface active compounds and (3) mixing the organic solution with the aqueous solution to form the multiphase system. The multiphase system can be shaken or mixed to form a crude emulsion. The raw emulsion will have oil droplets in the water about less than about 1 pm in diameter. The crude emulsion is sonicated to define a microemulsion and finally to define a suspension of submicron particles.

The water immiscible solvent is selected from the group consisting of linear, branched or cyclic alkanes of 5 or more carbons, linear, branched or cyclic alkenes of 5 or more carbons, linear, branched or cyclic alkynes of 5 or more carbons; aromatic hydrocarbons, fully or partially halogenated hydrocarbons, ethers, esters, ketones, mono-, di- or tri-glycerides, native oils, alcohols, aldehydes, acids, amines, linear or cyclic silicones, hexamethyldisiloxane or any combination of these solvents. A preferred water immiscible solvent is methylene chloride.

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The sonication step can be substituted by any other means that provides energy and examples of other energy sources are sonication, homogenization, microfluidization, countercurrent homogenization, or other methods that provide impact, shear stress, or cavitation forces.

Microprecipitation

The microprecipitation method is described in US Patent Application Serial No. 60 / 258,160; 09 / 874,799; 09 / 874,637; 09 / 874,499 and 09 / 953,979. Small particles of organic compounds are formed by the precipitation of an organic compound in an aqueous medium to form a pre-suspension, which is followed by the addition of energy to stabilize the coating of the particle or to modify the lattice structure of the particle. Preferably the process is used to prepare a suspension of a pharmaceutically active poorly water soluble compound suitable for parenteral or oral administration.

The process can be subdivided into two categories, Method A and Method B.

Method a

In Method A, the organic compound ("drug") is first dissolved in the first solvent to define a first solution. The organic compound can be added at about 0.1% (w / vol) to about 50% (w / vol), depending on the solubility of the organic compound in the first solvent. It may be necessary to heat the concentrate to between about 30 ° C and about 100 ° C to ensure complete dissolution of the compound in the first solvent.

A second aqueous solution is provided with one or more optional surface modifiers selected from anionic, cationic, nonionic surface active agents or a surface active biological molecule, added thereto.

It may also be convenient to add a pH adjusting agent to the second solution such as a buffer, sodium hydroxide, hydrochloric acid, tris buffer, citrate, acetate, lactate, meglumine or the like. Other buffers include amino acids such as glycine, leucine, alanine, lysine, and the like. The second solution should have a pH in the range of about 2 to about 11.

In a preferred form of the invention, the method for preparing submicron-sized particles of an organic compound includes the steps of adding the first solution to the second solution. The rate of addition depends on the batch size and the precipitation kinetics for the organic compound. Typically, for a small scale laboratory process (1 liter setup), the rate of addition is about 0.05 cc per minute to about 10 cc per minute. During the addition, the solutions must be under constant stirring. Using light microscopy, it is observed that amorphous particles, semi-crystalline solids or supercooled liquids are formed to define a presuspension. The method further includes the step of subjecting the presuspension to an annealing step to convert the amorphous particles, supercooled liquid or semi-crystalline solid to a more stable crystalline solid state. The resulting particles will have an effective mean particle size as measured by dynamic light scattering methods (e.g. photocorrelation spectroscopy, laser diffraction, low angle laser light scattering (LALLS), half angle laser light scattering ( MALLS), light obscuration methods (Coulter method, for example), rheology or microscopy (light or electron) within the ranges stated above).

The energy addition step involves the addition of energy by sonication, homogenization, countercurrent flow homogenization, microfluidization, or other methods that provide impact, shear stress, or cavitation forces. During this stage, the sample can be cooled or heated. In a preferred form of the invention, the annealing step is carried out in an interval piston homogenizer such as that sold by Avestin Inc. under the trade name EmulsiFlex-C160. In another preferred form of the invention, annealing can be carried out by ultrasonication using an ultrasonic processor such as the Vibra-Cell Ultrasonic Processor (600 W), manufactured by Sonics and Materials, Inc. In yet another preferred form of the invention, Annealing can be carried out using an emulsification apparatus such as described in US Patent No. 5,720,551.

Depending on the annealing speed, it may be convenient to adjust the temperature of the processed sample to the range of approximately -30 ° C to 30 ° C. Alternatively, in order to effect the desired phase change in the processed solid, it may also be necessary to heat the pre-suspension to a temperature in the range of about 30 ° C to about 100 ° C during the annealing step.

In addition to amorphous particles, semi-crystalline solids or a supercooled liquid, the pre-suspension can also be composed of friable crystals that are more easily pulverized than in their solid state before precipitation. In this case, the energy addition step breaks these particles down to a desired size.

IS 2 340 261 T3

Method b

Method B differs from Method A in the following respects. The first difference is a surfactant or combination of surfactants added to the first solution. The surfactants can be selected from nonionic, anionic, and cationic surfactants.

In addition to amorphous particles, semi-crystalline solids or supercooled liquid, the pre-suspension can also consist of friable crystals that are more easily pulverized than in their solid state before precipitation. In this case, the energy addition step breaks these particles down to a desired size.

An emulsion precipitation technique is described in commonly assigned and co-pending US Patent Serial No. 09 / 964,273. In this approach, the process includes the steps of (1) providing a multiphase system having an organic phase and an aqueous phase, the organic phase containing a pharmaceutically effective compound; and (2) sonicating the system so that a part of the organic phase evaporates, causing the compound to precipitate in the aqueous phase and with an effective average particle size of less than about 2 pm. The step of providing a multiphase system includes the steps of (1) mixing a water-immiscible solvent with the pharmaceutically effective compound to define an organic solution, (2) preparing a water-based solution with one or more surface active compounds, and (3) mix the organic solution with the aqueous solution to form the multiphase system. The mixing stage of the organic phase and the aqueous phase may include the use of interval piston homogenizers, colloidal mills, high speed stirring equipment, extrusion equipment, manual stirring or stirring equipment, microfluidizer or other equipment or techniques that provide high shear stress conditions. The raw emulsion will have oil droplets in the water less than about 1 pm in diameter. The crude emulsion is sonicated to define a microemulsion and finally to define a suspension of submicron particles.

An optional polymorphism control step can be performed during any of these steps and is discussed in detail below. The polymorphism control step can be carried out before or after sonication of the system. In an especially preferred form of the invention, the polymorphism control step is carried out during the sonication step.

Another approach to preparing submicron-sized particles is described in commonly assigned and co-pending US Patent Serial No. 10 / 183,035. The process includes the steps of: (1) providing a crude dispersion of a multiphase system having an organic phase and an aqueous phase, the organic phase containing a pharmaceutical compound; (2) provide energy to the crude dispersion to form a fine dispersion; (3) freeze the fine dispersion; and (4) lyophilizing the fine dispersion to obtain submicron size particles of the pharmaceutical compound. The step of providing a multiphase system includes the steps of (1) mixing a water-immiscible solvent with the pharmaceutically effective compound to define an organic solution; (2) preparing a water-based solution with one or more surface active compounds; and (3) mixing the organic solution with the aqueous solution to form the multiphase system. The stage of mixing the organic phase with the aqueous phase includes the use of interval piston homogenizers, colloidal mills, high-speed stirring equipment, extrusion equipment, manual stirring or stirring equipment, microfluidizers, or other equipment or techniques. that provide high shear stress conditions.

The polymorphism control step detailed below can be carried out during any of these steps. In a particularly preferred form of the invention, the polymorphism control step is carried out in the mixing step (3) of the step consisting of providing a multiphase system.

Precipitation with Solvent and Antisolvent

A suitable solvent and antisolvent precipitation technique is described in US Patent Nos. 5,118,528 and 5,100,591. The process includes the steps of (1) preparing a liquid phase of a biologically active substance in a solvent or in a mixture of solvents to which one or more surfactants can be added; (2) preparing a second liquid phase of a non-solvent or non-solvent mixture, the non-solvent being miscible with the solvent or solvent mixture for the substance; (3) add the solutions of (1) and (2) together with stirring; and (4) removing unwanted solvents to produce a colloidal suspension of nanoparticles. The patent 5,118,528 describes the production of particles of the substance smaller than 500 nm without supplying energy.

As mentioned above, the optional polymorphism control step discussed in detail below can be performed during any of these steps. In an especially preferred form of the invention, the polymorphism control step is carried out in step (3) before the solutions (1) and (2) are added together.

Phase Inversion Precipitation

Suitable phase inversion precipitation is described in US Patent Nos. 6,235,224, 6,143,211 and in US Patent Application No. 2001/0042932. Phase inversion is a term used to describe the physical phenomena whereby a polymer dissolved in a solvent system as a phase

The continuous ES 2 340 261 T3 is inverted into a solid macromolecular network in which the polymer is the continuous phase. One method of inducing phase inversion is by adding a non-solvent to the continuous phase. The polymer undergoes a transition from a single phase to an unstable mixture of two phases: polymer-rich fractions and polymer-poor fractions. The non-solvent micellar droplets in the polymer-rich phase serve as nucleation sites and are coated with polymer. Patent No. 6,235,224 indicates that phase inversion in polymer solutions under certain conditions can cause spontaneous formation of discrete microparticles, including nanoparticles. Patent No. 6,235,224 describes dissolving or dispersing a polymer in a solvent. A pharmaceutical agent is also dissolved or dispersed in the solvent. For an optional polymorphism control step to be effective in this process, it is desirable that the agent is dissolved in the solvent. The polymer, agent, and solvent together form a mixture having a continuous phase, with the solvent being the continuous phase. The mixture is then introduced in an excess of at least ten times a miscible non-solvent to cause the spontaneous formation of microencapsulated microparticles of the agent, with an average particle size between 10 nm and 10 pm. The particle size is influenced by the volume ratio of solvent: non-solvent, the polymer concentration, the viscosity of the polymer-solvent solution, the molecular weight of the polymer, as well as the characteristics of the solvent-non-solvent pair. The process eliminates the step of creating microdroplets, such as by emulsion formation, of the solvent. The process also avoids agitation and / or shear stresses.

The optional polymorphism control step detailed below can be performed during any of these steps. In an especially preferred form of the invention, the polymorphism control step is carried out before or during the addition of the non-solvent to the continuous phase.

Precipitation due to pH change

PH change precipitation techniques typically include a step of dissolving a drug in a solution at a pH at which the drug is soluble, followed by the step of changing the pH to a point where the drug is no longer soluble. it is soluble. The pH can be acidic or basic, depending on the particular pharmaceutical compound. The solution is then neutralized to form a pre-suspension of submicron-sized particles of the pharmaceutically active compound. A suitable pH change precipitation process is described in US Patent No. 5,665,331. The process includes the step of dissolving the pharmaceutical agent with a crystal growth modifier (CGM) in an alkaline solution and then neutralizing the solution with an acid in the presence of one or more suitable surface-modifying surface active agents. to form a fine particle dispersion of the pharmaceutical agent. The precipitation step can be followed by steps of cleaning the dispersion by diafiltering the dispersion and then adjusting the concentration of the dispersion to a desired level. This process, according to the information received, leads to microcrystalline particles with mean Z diameters less than 400 nm as measured by photon correlation spectroscopy.

The optional polymorphism control step detailed below can be performed during any of these steps. In a preferred form of the invention, the polymorphism control step is carried out before or during the neutralization step.

Other examples of pH shift precipitation methods are described in US Patent Nos. 5,716,642, 5,662,883, 5,560,932, and 4,608,278.

Infusion Precipitation Method

Suitable infusion precipitation techniques are disclosed in US Patent Nos. 4,997,454 and 4,826,689. First, an appropriate solid compound is dissolved in a suitable organic solvent to form a solvent mixture. Then, a precipitating non-solvent miscible with the organic solvent is infused into the solvent mixture at a temperature between about -10 ° C and about 100 ° C and at an infusion rate of about 0.01 ml per minute at about 1,000 ml per minute by volume of 50 ml, to produce a suspension of precipitated non-aggregated solid particles of the compound with a substantially uniform mean diameter of less than 10 pm. It is preferred to stir the solution being infused with the precipitating non-solvent. The non-solvent may contain a surfactant to stabilize the particles against aggregation. The particles are then separated from the solvent. Depending on the solid compound and the desired particle size, the parameters of temperature, ratio of non-solvent to solvent, infusion rate, stirring rate, and volume may vary in accordance with the invention. The particle size is proportional to the ratio between the non-solvent: solvent volumes and the infusion temperature is inversely proportional to the infusion speed and the stirring speed. The precipitation non-solvent may be aqueous or non-aqueous, depending on the relative solubility of the compound and the desired suspension vehicle.

The optional polymorphism control step detailed below can be performed during any of these steps. In a preferred form of the invention, the polymorphism control step is carried out before or during the infusion of the non-solvent.

Precipitation by Temperature Change

The temperature change precipitation technique, also known as the hot melt technique, is described in US Patent No. 5,188,837 to Domb. In one embodiment of the invention,

ES 2 340 261 T3 lipospheres by the steps of (1) melting or dissolving a substance, such as a drug to be delivered, in a molten carrier, to form a liquid of the substance to be delivered; (2) adding a phospholipid together with an aqueous medium to the molten substance or vehicle at a temperature higher than the melting temperature of the substance or vehicle; (3) mixing the suspension at a temperature above the melting temperature of the vehicle until a fine homogeneous preparation is obtained; and then (4) rapidly cooling the preparation to or below room temperature.

The optional polymorphism control step detailed below can be performed during any of these steps, as long as the processing temperatures do not exceed the melting point of the drug. In a particularly preferred form of the invention, the polymorphism control step is carried out before the step of cooling the hot drug dispersion.

Solvent Evaporation Precipitation

Solvent evaporative precipitation techniques are described in US Patent No. 4,973,465. Patent No. 4,973,465 describes methods for preparing microcrystals that include the steps of: (1) providing a solution of a pharmaceutical composition and a phospholipid dissolved in a common organic solvent or in a combination of solvents, (2) evaporating the solvent or solvents and (3) suspending the film obtained by evaporation of the solvent or solvents in an aqueous solution by strong stirring. The solvent can be removed by adding energy to the solution so that a sufficient amount of solvent evaporates and causes precipitation of the compound. The solvent can also be removed by other well-known techniques, such as applying a vacuum to the solution or blowing nitrogen over the solution. The optional polymorphism control step detailed below can be performed during any of these steps. In a particularly preferred form of the invention, the polymorphism control step is carried out before the evaporation step.

Reaction Precipitation

Precipitation by reaction includes the steps of dissolving the pharmaceutical compound in a suitable solvent to form a solution. The compound must be added in an amount at or below the saturation point of the compound in the solvent. The compound is modified by reaction with a chemical agent or by modification in response to the addition of energy, such as heat or UV light or the like, such that the modified compound has a lower solubility in the solvent and precipitate out of solution. The optional polymorphism control step detailed below can be performed during any of these steps. In a particularly preferred form of the invention, the polymorphism control step is carried out before or during the precipitation step.

Precipitation by Compressed Fluid

A suitable compressed fluid precipitation technique is described in WO 97/14407 to Johnston. The method includes the steps of dissolving a water-insoluble drug in a solvent to form a solution. The solution is then sprayed into a compressed fluid, which can be a gas, a liquid, or a supercritical fluid. The addition of the compressed fluid to a solution of a solute in a solvent causes the solute to reach or approach the supersaturated state and to precipitate out into fine particles. In this case, the compressed fluid acts as an antisolvent that lowers the cohesive energy density of the solvent in which the drug is dissolved.

Alternatively, the drug can be dissolved in the compressed fluid which is then sprayed into an aqueous phase. The rapid expansion of the compressed fluid reduces the solvent capacity of the fluid, which in turn causes the solute to precipitate out into fine particles in the aqueous phase. In this case, the compressed fluid acts as a solvent.

In order to stabilize the particles against aggregation, a surface modifier, such as a surfactant, is included in this technique. The particles prepared by this technique are generally 500 nm or smaller.

The optional polymorphism control step detailed below can be performed during any of these steps. In a particularly preferred form of the invention, the polymorphism control step is carried out before or during the particle formation step.

Suspension method

The other method for preparing aqueous suspensions of nanoparticles is the suspension method. In this method, the particles of the pharmaceutical agent are dispersed in an aqueous medium by adding the particles directly to the aqueous medium, to obtain a pre-suspension. The particles are normally coated with a surface modifier to inhibit aggregation of the particles. One or more excipients can be added to the pharmaceutical agent or aqueous medium.

IS 2 340 261 T3

Energy can be added to the pharmaceutical agent or to the pre-suspension to reduce the particle size of the pharmaceutical agents to the desired particle size. Examples of energy sources include, but are not limited to, sonication, homogenization, microfluidization, countercurrent homogenization, or other methods that provide impact, shear stress, or cavitation forces.

Polymorphism Control

Methods for preparing a suspension may further include the crystal seeding step to control the crystal structure of the drug. By the term "crystal structure" is meant the arrangement and / or conformation of the molecules within the crystal lattice. Compounds that can crystallize into different crystal structures are said to be polymorphic. The identification of polymorphs is an important stage in the formulation of drugs, since different polymorphs of the same drug may show differences in their solubility, therapeutic activity, bioavailability and stability of the suspension. Similarly, different polymorphs of the same excipient may show differences in solubility, compatibility with the drug to be delivered, chemical stability, and suspension stability. Consequently, it is important to control the polymorphic form of the compound to ensure product purity and batch-to-batch reproducibility.

The polymorphic form of the compound in the process set forth above can be controlled by the additional seeding step. Seeding includes the use of a seed compound or the addition of energy to form a seed compound. In a preferred form of the invention, the seed compound is the pharmaceutically active compound in the desired polymorphic form. Alternatively, the seed compound can also be an inert impurity or an organic compound with a structure similar to that of the desired polymorph.

The seed compound can be precipitated from a solution containing the drug by any of the processes described above. This method includes the steps of adding the pharmaceutically active compound in an amount sufficient to exceed the solubility of the pharmaceutically active compound in the first solution, creating a supersaturated solution. The supersaturated solution is treated to precipitate the pharmaceutically active compound in the desired polymorphic form. Treatment of the supersaturated solution includes aging the solution for a period of time until the formation of a crystal or crystals is observed to create a seed mixture. Treatment of the solution also includes subjecting the solution to a change in temperature or change in pH. It is also possible to add energy to the supersaturated solution so that the pharmaceutically active compound precipitates out of solution into the desired polymorph. Energy can be added in a number of ways, including the energy addition steps described above. More energy can be added by heating or exposing the pre-suspension to electromagnetic energy sources, particle beam or electron beam. Electromagnetic energy includes the use of a laser beam, dynamic electromagnetic energy, or other sources of radiation. The use of ultrasound, static electric field and a static magnetic field as a source of energy addition is also contemplated.

In a preferred form of the invention, the method of producing seed crystals from an aged supersaturated solution includes the steps of: (i) adding a quantity of pharmaceutically active compound to a drug solution to create a supersaturated solution, (ii) ) aging the supersaturated solution to form detectable crystals, creating a seed mixture; and (iii) precipitating the seed mix to create a pre-suspension. The pre-suspension can then be further processed as described herein to provide an aqueous suspension of the pharmaceutically active compound in the desired polymorph and in the desired size range.

Seeding can also be accomplished by adding energy to the first solution or to the pre-suspension to form the seeding compound, provided that the exposed liquid or liquids contain the pharmaceutical compound or a seed material. Energy can be added in the same way as described above for the supersaturated solution.

Accordingly, a subject composition of a pharmaceutical compound is disclosed in a desired polymorphic form essentially free of unspecified polymorph (s). It is contemplated that the methods of this invention may be applied using them to selectively produce a desired polymorphism for numerous pharmaceutical compounds.

6. Sterilization of the composition

The composition can be sterilized or thermally filtered, then aseptically processed prior to freezing, depending on the thermal stability of the particular components of the composition and the particle size of the composition. The preferred method for the production of a sterile product is to filter the selected components, followed by an aseptic manufacturing process before freezing. An alternative method of sterilization for the invention is gamma radiation before or after the freezing step.

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Examples

Example 1

Preparation of an itraconazole suspension by microprecipitation Method A with homogenization, followed by freezing of the suspension

Surfactant Solution: 3,500 ml of distilled water, 22 g of glycerin, 22 g of poloxamer 407, and 22 g of poloxamer 188 are added to a 4-liter flask. The surfactant solution is heated and stirred to dissolve the solids. . The surfactant solution is cooled and diluted to 4 liters with distilled water.

Itraconazole concentrate: 15 g of itraconazole and 67.5 g of lactic acid are combined in a 100 ml beaker. The mixture is heated to dissolve the solids. The itraconazole concentrate is cooled to room temperature.

Presuspension: The itraconazole concentrate is transferred to a 60 ml syringe. 1.5 liters of surfactant solution is transferred to the hopper of a jacketed homogenizer. A rod stirrer is positioned in the diluent solution until the mixing blades are fully submerged. Using a syringe pump, slowly add the itraconazole concentrate to the diluent solution while mixing.

Homogenized Suspension: The pre-suspension is immediately homogenized (10,000 psi) for approximately 20 minutes.

Final suspension: Excess lactic acid is removed by centrifugation of the homogenized suspension for 20 minutes. The supernatant is discarded and the solids are resuspended in a surfactant solution consisting of a fresh surfactant solution. The suspension is mixed by centrifugation for 20 minutes. The supernatant is discarded and the solids are resuspended in a surfactant solution composed of a fresh supernatant solution. The resuspended sample is homogenized for approximately 20 minutes at 10,000 psi. The final pH of the suspension is approximately 4. The suspension is collected in 50 ml bottles and sealed with coated stoppers.

Frozen suspension: 3-50 ml samples of the final suspension are placed in a -20 ° C freezer and 3-50 ml samples of the final suspension are stored at 2-8 ° C. After approximately 1 month, the samples are removed from storage at -20 ° C and allowed to thaw under ambient conditions. Samples are transferred at 2-8 ° C. No phase separation, visible aggregation or agglutination is observed. The sample that was subjected to freezing and controls, which was stored at 2-8 ° C, is tested for particle size distribution by laser light scattering. There are no discernible differences in particle size distribution between frozen samples and controls (see below).

<td>Sample ID</td><td>Average Particle Size</td><td>Particle size 99%</td>

<td>Control 1</td><td> 0,243</td><td> 0,510</td>

<td>Control 1 1 min. sonication</td><td> 0,238</td><td> 0,510</td>

<td>Control 2</td><td> 0,240</td><td> 0,510</td>

<td>Control 2 1 min. sonication</td><td> 0,247</td><td> 0,510</td>

<td>Control 3</td><td> 0,250</td><td> 0,510</td>

<td>Control 3 1 min. sonication</td><td> 0,266</td><td> 0,510</td>

<td>Freeze 1</td><td> 0,246</td><td> 0,510</td>

<td>Freeze 1 1 min. sonication</td><td> 0,261</td><td> 0,510</td>

<td>Freeze 2</td><td> 0,232</td><td> 0,510</td>

<td>Freeze 2 1 min. sonication</td><td> 0,245</td><td> 0,510</td>

<td>Freeze 3</td><td> 0,236</td><td> 0,510</td>

<td>Freeze 3 1 min. sonication</td><td> 0,241 _</td><td> 0,510</td>

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It is reasonable to think that the frozen suspension will be stable for a year or more under these storage conditions.

Comparative Example 2

Amorphous Itraconazole Nanosuspensions Stabilize By Storage at -70 ° C

Itraconazole (4.0 grams) is dissolved in 20 ml of methylene chloride and combined with 400 ml of a 5% albumin solution (diluted from 25%). The combined solutions are stirred manually to disperse the two liquids. The crude emulsion is then sonicated (T = 5 ° C) for 6 minutes (sonication every 30 seconds by means of a 1 ”(2.5 cm) probe at 40% amplitude). The sonicated solution is rotary evaporated under in-house vacuum (~ 100 torr) for about 1/2 hour, and then under pump vacuum (&lt;20 torr) for about 2 hours. The rotary evaporated product is analyzed by light scattering detection (Horiba), revealing particles with a mean diameter of 406 nm. This product is then shipped to Galbraith Laboratories, Inc., for analysis by GC-Headspace, revealing that the methylene chloride concentration is 12.3 ppm. Visible light microscopy inspection shows that the particles are spherical in shape with no evidence of crystallinity. Furthermore, X-ray diffraction analysis on the particles produced by this method confirms that they are totally amorphous.

Approximately 35 ml of the product is stored at -70 ° C for 32 days. Re-analysis of the suspension by HORIBA light scattering detection and microscopic examination reveals essentially no change in particle size (mean value 427 nm). It is reasonable to think that the frozen suspension will be stable for a year or more under these storage conditions.

Comparative Example 3

1% or Budesonide in a PEG-Phospholipid Surfactant System

Ingredients:

1% Budesonide

1.2% mPEG-PSPE, MW 2000

2.25% glycerin

0.14% dibasic sodium phosphate.

A weighted amount of mPEG-PSPE (palmitoyl-stearoyl-phosphatidylethanolamine) and a volume of a previously prepared aqueous solution containing 2.25% glycerin and 0.14% dibasic sodium phosphate at a pH of 8.6 they are combined and mixed by means of a high shear mixer. The drug is added and the combination is mixed under high shear stress to form a pre-suspension. The pre-suspension is homogenized for 30 discrete steps at a pressure of 25,000 psi.

A portion of the sample is frozen at -20 ° C for 24 hours and then allowed to completely thaw at room temperature.

<td colspan="3">Particle size results (measured by laser diffractometry)</td>

<td>Diameter (Volume Weight)</td><td>Initial (microns)</td><td>After Freezing Defrosting (microns)</td>

<td>Average</td><td> 0,8472</td><td> 0,8371</td>

<td>99th percentile</td><td> 1,688 1,685</td><td></td>

IS 2 340 261 T3

Comparative Example 4

1% Nabumetone with Albumin Surfactant

Ingredients:

5% human albumin

1% Nabumetone.

A volume of albumin solution and a weighted amount of the drug are combined and mixed under high shear stress to form a pre-suspension. The pre-suspension is homogenized for 30 discrete steps at a pressure of 25,000 psi.

A part of the sample is homogenized at -20 ° C for 24 hours and then allowed to completely thaw at room temperature.

<td colspan="3">Particle size results (measured by laser diffractometry)</td>

<td>Diameter (Volume Weight)</td><td>Initial (microns)</td><td>After Freeze Defrost (microns)</td>

<td>Average</td><td> 0,7721 0,7940</td><td></td>

<td>99th percentile</td><td> 1,889</td><td> 1,936</td>

Example 5

1% Nabumetone with Surfactant with Polyalkoxyether and Bile Salt

Ingredients:

2.2% Poloxamer 188

0.1% sodium deoxycholate

2.2% glycerin

1% Nabumetone.

A weighted amount of the drug and a volume of a solution containing 2.2% Poloxamer 188, 0.1% sodium deoxycholate and 2.2% glycerin adjusted to pH 8.7 are combined and they mix under high shear stress to form a pre-suspension. The pre-suspension is homogenized for 20 discrete steps at a pressure of 25,000 psi.

A part of the sample is frozen at -20 ° C for 24 hours and then allowed to completely thaw at room temperature.

<td colspan="3">Particle size results (measured by laser diffractometry)</td>

<td>Diameter (Volume Weight)</td><td>Initial (microns)</td><td>After Freeze Defrost (microns)</td>

<td>Average</td><td> 1,0498</td><td> 1,085</td>

<td>99th percentile</td><td> 2,423</td><td> 2,484</td>

IS 2 340 261 T3

Comparative Example 6

1% Budesonide with PEG-Fatty Acid Ester

Ingredients:

0.125% Solutol

2.25% glycerin

1% Budesonide.

A weighted amount of the drug and a volume of a solution containing 0.125% solutol and 2.25% glycerin adjusted to a pH of 8.7 are combined and subjected to a high shear mixing to form a pre-suspension. . The pre-suspension is homogenized for 30 discrete steps at a pressure of 25,000 psi.

A part of the sample is frozen at -20 ° C for 24 hours and then allowed to completely thaw at room temperature.

<td colspan="3">Particle size results (measured by laser diffractometry)</td>

<td>Diameter (Volume Weight)</td><td>Initial (honeys)</td><td>After Freeze Defrost. (honeys)</td>

<td>Average</td><td> 0,7587</td><td> 0,7641</td>

<td>99th percentile</td><td> 1,460</td><td> 1,480</td>

Comparative Example 7

Ingredients:

1% Vitamin E TPGS (d-alpha-tocopheryl polyethylene glycol-1000 succinate)

1% Nabumetone

2.25% glycerin

0.14% dibasic sodium phosphate.

A weighted amount of Vitamin E TPGS and a volume of a ready-made aqueous solution containing 2.25% glycerin and 0.14% dibasic sodium phosphate are combined at a pH of 8.6. The mixture is vortexed until the Vitamin E TPGS dissolves. The drug is added and the mixture is subjected to the UltraTurrax homogenate disperser to form a pre-suspension. The pre-suspension is homogenized with an Avestin B3 homogenizer for 30 discrete steps at a pressure of 25 kpsi.

A portion of the sample is frozen at -20 ° C for 24 hours, then allowed to completely thaw at room temperature.

<td colspan="3">Particle size results</td>

<td>Diameter (Volume Weight)</td><td>Initial (honeys)</td><td>After Freeze Defrost. (honeys)</td>

<td>non-sonicated 99th percentile</td><td> 2,372</td><td> 2,593</td>

<td>sonicate 99th percentile</td><td> 2,266</td><td> 2,398</td>

<td>Sonicated average *</td><td> 1,0332</td><td> 1,0333</td>

Although specific embodiments have been illustrated and described, numerous modifications can be made and the scope of protection is only limited by the scope of the appended claims.