Therapeutic suspensions of steroids containing pvp and/or pva

2,861,920

Patented Nov. 25, 1958

2,861,920

THERAPEUTIC SUSPENSIONS OF STEROIDS CONTAINING PVP AND/OR PVA ^JazL^KTX!eh-^KalTzⁿ!^aZ00’ ^aild Samuel L. Ross, Kalamazoo Township Kalamazoo County, Mich., assignors to

No Drawing. Application May 4,1954 Serial No, 427,678

Claims. (Cl. 167—65) ^to compositions of matter preparation containin^°^{re par}X^ularly’. * elates to compositions ^«taming an insoluble steroid in combination with one C bp;^hydrX^{hll!C pPlyvinyl} compounds, said Combinastable for th ’“’I· ^fOTm °^f “ “fincous suspension suitable for therapeutic use or iff the form of a drv adtton o/ ^{Whlch IS smt}able for the extemporaneous preparaa nrX^{an a}^™.A¹³· The invention also relates to a process for inhibiting crystal growth of steroids. solnW ^P7^parj^t!T °^{f Stable} dfideous suspensions of inFdrexXniA ^{S has presentea} considerable difficulties, acetate ^saspensions crystalline cortisone pro_cestei one, testosterone propionate, estradiol mowth^enTh-^e,-^{and th}® ^Iike’ ^are characterized by crystal growth. This is a real problem since large crystals can ^b® ^a.^soa!'ce of great irritation to patients, can cause methrffiieh fin^ffih^UltI? ^,n.^attempiinS to pass large crystals effect unbnth^yP° ^dIes’ ^{and have a} considerable effect upon the suspendability of the active material So httle is known about the mechanism of crystal growth that it is almost impossible to predict what materials or methods will retard it.

It is an object of the invention to provide novel comareX? f^mat5^{er COnta}.^ining “soluble steroids which are suitable for tnerapeutic Use. Another object of the nvention is to provide stable aqueous suspensions of steroids suitable for therapeutic use which will remain relatively free of crystal growth, even after extended

X T®’ ^An.^other object of the invention is to ^pr°.^{Vlde d}7 therapeutic compositions containing a steroid h ch will readily form a stable suspension on the addition, ot an aqueous vehicle without being subject to excessive crystal growth. , Other objects are to provide novel procedures for preparing such compositions and novel ways of inhibiting the crystallization of steroids. Still Xm¹?^bjl^CtS °^{f the} “^vention will be apparent to those smiled m the art to which this invention pertains . The invention provides compositions of matter containing a hydrophilic polyvinyl compound such as polyvinyl pyrrolidone, polyvinyl alcohol, or the like, and mixtures thereof, m combination with a steroid such as Cortisone acetate, progesterone, testosterone propionate, estradiol monobenzoate, or the like, said compositions being either in the form of an aqueous suspension or in the iorm of a dry admixture readily dispersible to form the same These suspensions are characterized by the absence of excessive crystal growth.

The marked superiority of the hydrophilic polyvinyl compounds of the invention as crystal growth fetardants for therapeutic steroid compositions as compared with other suspending agents is clearly evident from the data set fortn m the following tables. Thus, steroid suspensions prepared according to the invention are characterized by the absence of undue crystal growth in suspension even aftei storage for extended periods of time at room temperature.

, The following tables compare the effect of two hydrophilic polyvinyl .compounds with other.. suspending ^:i8^ents on the crystal ..growth of a steroid, illustratively cortisone acetate aiid cortisone acetate hydrate, the comparisons being maoe after storage at room temperature eXX J^^ioupi^mes indicated. Table I illustrates the ^{10 h}y^droPhihc polyvinyl compounds on the crydal growth of cortisone acetate as compared with other suspending agents. The cortisone acetate is in aqueous suspension in the concentration of fifteen miliigrams per cubic centimeter with 0.1 percent weight by volume of the suspending agent. ^{S Y}

TABLE I

The effect of various suspending agents on the crystal

-growth of cortisone acetate in suspension

Suspending Agent

Crystal Size

Initial days wks.

Polyvinyl Alcohol.

Polyvinylpyrrolidone .

Acaeia U. S. P_...

Dextran.._____________ΣΣΖΣΣΖΖΣ^-”

Sodium Oarboxymethyieelluiose'

Pectin N. F______

Sodium Alginate___ΖΣΖΣΣΖΣΖΣΣΖΣΖΣ <10/1 <I0*< <10*1 <10/1 <10*1 <10*1 <10/1 <10/1 <10/1 100%>10<ι 50%>10μ 20%>10_Jtl80%>10/ι 60%>10μ .

<10/1 <10*1 ’ mos.

<10*i <10*·

From, the data given in Table I it will be seen that only ^C°^{h01 aHd pcl}-^vv‘^nyi Pyrrolidone effectively inhibited the crystal growth of cortisone acetate.

, Table II illustrates the effect of the hydrophilic polvXA^Ci?T^Unds °^{n the Crystal growth of} cortisone acetate hydrate as compared, with other suspending agents ^saspeif^on contained fifteen milligrams per cubic centimeter of cortisone, acetate hydrate, 0.1 percent suspending agent, and .0.02 percent “Quatresin” (myristyl gamma picolimum chloride) as a preservative.

TABLE II

The effect of various suspending agents on the crystal growth of cortisone acetate in aqueous suspension

<td rowspan="2"> Suspending Agent ⁴⁰ - -......- .</td><td colspan="4"> Crystal Size</td>

<td> Initial</td><td> 4 days</td><td> 3 wks.</td><td> 2 mos.</td>

<td> Polyvinyl Alcohol. Polyvinylpyrrolidone Acacia U. S. P..... ' Dextran..__________ ^S°ose^{m Carboxymet}jwj^hu-' 45 Pectin N. F__________ Sodium Alginate..._____</td><td> &lt;10/. &lt;10*i &lt;10*1 &lt;10*. &lt;10*. &lt;10*. &lt;10*.</td><td> &lt;10*. &lt;10μ 100%&gt;10*i 100%&gt;10*_t 40%&gt;10*i 80%&gt;10_μ10%&gt;10*l</td><td> &lt;10*. &lt;w</td><td> : &lt;10*i 10%&gt;10*i</td>

The data given _{in Tab]e n shows only}alcohol and polyvinyl pyrrolidone of the suspending agents tested inhibit growth of cortisone acetate hydrate, table ill illustrates various preservatives which can be substituted for Quatresin” and the effect of the preservatives on the crystal growth of cortisone acetate hydrate m aqueous suspensions. No suspending agent was used.

TABLE III

The effect of various preservatives on the crystal growth of cortisone acetate in aqueous suspension

Crystal Size

Preservative

<td></td><td> Initial</td><td> 1 day</td><td> 2 wks.</td><td> 2 mos.</td>

<td> 0.02% “Quatresin”. (myristyl gamma picolinium chloride).......____ ⁰⁰ 0.01% “Merthiolate” (sod!um ethylmercurithlosalicylate)..... ........... 0.5% Ohiorobutanol..;_...* 0.5% Benzyl Alcohol....... 1.5% Benzyl Alcohol. ...·.¹ 0.5% Phenol_______________ 70 θ-1% Methylparaben______ Deionized water (control);, i</td><td> &lt;10*i &lt;10/1 &lt;10*i &lt;10*i &lt;10*1 &lt;10*1 &lt;10/1 &lt;10*1</td><td> l%&gt;10*. &lt;10*/ &lt;10*&gt; ,10%&gt;10*1 100%&gt;10*i 100%&gt;10„ 1%&gt;10μ 0.1%&gt;1O*1</td><td> 1%&gt;10μ 1%&gt;10μ 1%&gt;10μ. ~1%&gt;ίθμ</td><td> 100%&gt;10*ι 100%&gt;10μ 100%&gt;10*ι 100%&gt;10*ι 100%&gt;10μ 100%&gt;Ϊ0μ 100%&gt;10μ 100%&gt;10μ</td>

The data given in Table III shows that neither “Quatresin nor any of the other preservatives tested have any apparent inhibitory effect on the crystal growth of cortisone acetate hydrate in aqueous suspension.

The following table illustrates the crystal growth in aqueous suspensions of cortisone acetate hydrate (at a concentration of fifteen mgs./cc.) containing various suspending agents after storage at room temperature for various periods of time and the re-suspendibility of these suspensions after an extended period of time. In all instances, 0.1 percent weight by volume of the suspending agent is used.

TABLE IV

Re-suspendibility

Crystal Growth

Suspending Agent

Initial, Shakes mos., Shakes

Initial wks.

Polyvinyl Alcohol----Polyvinyl PyrrolidoneAcacia U. S. P--------Dextran.-.-------Sodium Carboxymethylcellulose.

Pectin N. F-----------Methylcellulose-------Sodium Alginate------3-10

3-10 1-2 1-2

1-2 1-2 1-2

13_____________

1-2____________

3-10___________ dried up-----20 (clumped) 20 (dumped) „ (clumped)1-2____________ &lt;10μ &lt;10μ &lt;10μ &lt;10μ &lt;10μ &lt;10μ &lt;10μ &lt;10μ

2,881,920 ⁴tion are of pharmaceutical grade, non-toxic, inert and capable of being sterilized without change in composition. On the addition of water to a dry composition containing a steroid and the selected hydrophilic polyvinyl compound, followed by mixing, a stable steroid suspension is readily obtained. . . ., ... „

The polyvinyl pyrrolidone used in the compositions described herein is sold by the General Aniline and Film Company under the trademark “Plasdone and is characterized by a viscosity coefficient, i. e., K value, of 26 to 36 and a molecular weight of about 40,000. However, it is to be understood that the invention is not to be limited to the use of this specific polyvinyl pyrrolidone since other equivalent polyvinyl pyrrolidones of pharmaceutical grade are likewise suitable. While a polyvinyl pyrrolidone of pharmaceutical grade possessing a molecular weight between twenty and eighty thousand is preferred, satisfactory results are also obtained by the use of a polyvinyl pyrrolidone outside of this molecular weight range.

, The polyvinyl alcohol utilized in the compositions described herein is sold by the DuPont Company under the trademark “Elvanol” 51-05 and is characterized by a viscosity of four to six centipoises (four percent aqueous solution at twenty degrees centigrade), a pH of six to eight and a 86 to 89 percent hydrolysis from polyvinyl acetate. It is to be understood, however, that the invention is not limited to the use of this specific polyvinyl alcohol since any other equivalent polyvinyl alcohol of pharmaceutical grade can likewise be used to achieve similar results. .., ,

The amount of hydrophilic polyvinyl compound which can be used in the compositions of the invention can vary from a range of 0.01 percent weight by volume up to ten percent weight by volume. However, the preferred range of concentration is between 0.1 to five percent weight by volume. The preferred range varies with the type ot preparation however. For example, for an eye preparation, a concentration of about 0.1 to about 0.4 percent weight by volume is preferred. Higher concentrations make eyelids sticky. For injection use concentrations of one to two percent are preferred to keep the suspension from darkening. .

The compositions of the present invention are especially suitable for therapeutic application either parenterally, orally, or topically. For example, sterile aqueous suspensions of cortisone acetate, cortisone acetate hydrate, and the like, are especially useful as topical ophthalmic *&lt;10μ ·&lt;10μ 50%, 20—ΙΟΟμ 00%,20-80μ 100%, 10-40μ

20%&gt;10μ 20%—10μ 100%, 20-β0μ *No crystal growth after ten months.

Since the clumps obtained in the three instances noted above could not be broken up, suspensions of this type are unsatisfactory for ophthalmic use or injection and are generally unsuitable for therapeutic use because of lack of uniformity in dosage.

Of the suspending agents tested, only the aqueous suspensions of cortisone acetate hydrate containing polyvinyl alcohol and polyvinyl pyrrolidone were both readily resuspendible and free of crystal growth. These suspensions are therapeutically useful, especially for ophthalmic use or parenteral injection.

Table V illustrates the effect of suspending agents set forth in Table I and “Quatresin,” on crystal growth in aqueous suspensions of cortisone acetate hydrate (at a concentration of fifteen mgs./cc.) after storage at room temperature for various periods of time and also the resuspendibility of these suspensions after an extended period of time. In all instances, 0.02 percent Quatresin and 0.1 percent suspending agent, weight by volume, are used.

TABLE V

<td rowspan="2"> “Quatresin” 4- Suspending Agent</td><td colspan="2"> Re-suspendibility</td><td colspan="2"> Crystal Growth</td>

<td> Initial, Shakes</td><td> 10 mos., Shakes</td><td> Initial</td><td> 3 wks.</td>

<td> Polyvinyl Alcohol-------- - Polyvinyl Pyrrolidone........... Acacia u. S. P------------------- Dextran-------------— Sodium Carboxymethylcellulose. Pectin N. F---------------------- Methylcellulose------------------ Sodium Alginate-.-.--------— Control—only 0.02% “Quatresin”.</td><td> 3-10___________ 3-10___________ &gt;10 (caked)— &gt;10 (caked)— 1-2____________ 1-2____________ 1-2____________ 1-2____________ 1-2____________</td><td> 3-10........... 3-10___________ &gt;20 (caked)— &gt;20 (caked)... &gt;20 (caked)... &gt;20 (caked)... &gt;20 (caked)— 1-2____________ 1-2............</td><td> &lt;10μ &lt;10μ &lt;10μ &lt;10μ &lt;10μ &lt;10μ &lt;]0μ &lt;10μ &lt;10μ</td><td> &lt;10μ 1%&gt;10μ 100%, 20-80μ 100%, 10-70μ 100%, 20-80μ 100%, 20-00μ 20%, ΙΟμ 100%. 20-60μ 20%&gt;10μ</td>

In combination with “Quatresin,” only the aqueous suspensions of cortisone acetate hydrate containing polyvinyl alcohol and polyvinyl pyrrolidone were readily re-suspendible and free of crystal growth. _

The cortisone acetate hydrate used herein is conveniently prepared by dissolving cortisone acetate in a watermethanol mixture (e. g., 100 grams of cortison acetate is dissolved in a. mixture of 250 milliliters of water and 25 liters of methanol), filtering the mixture to remove impurities, allowing the filtrate to crystallize and carefully drying the crystals to obtain cortisone acetate in its hydrated form. ,

The polyvinyl hydrophilic compounds o£ the inyen,65 ——______j. Ophthalmic preparations of this nature are not perceptible in the eye and are non-irritating. For oral use, cortisone acetate, progesterone, and the like, are especially suitable. .

Furthermore, other therapeutic materials can be incorporated with the compositions containing the selected hydroohilic polyvinyl compound and steroid to form new and extremely valuable compositions. Such therapeutic materials include antibiotics such as neomycin, penicillins such as penicillin G, penicillin O, procaine penicillin, and the like, bacitracin, chloramphenicol, streptomycin, dihydrostreptomycin, erythromycin, oxytetracyclme, chlortetracycline, tetracycline, polymyxin, circulm, endomycin,

8;8Ϊϊί,92ϋ n?e?S°·^{miXtUres of lhese} antibiotics. It should be with a steroid‘Aria A ^{t&gt;f corabulations} of an:antibiotic as fnr « P^arPcLllarly valuable for therapeutic use such ^pensions because their characteristic wetting actSn ίΚχ·£ *» “ **·»*·· «I sss nd sealed. In preparing a suspension of a steroid such as progesterone, cortisone acetate, or the like the stemW is micronized or otherwise prepared in the&gt; desiredmarf icle size, sterilized, for example, by exposure to ethvfen? oxide vapor, and then combined with a suitable vehicle o form a suspension. Particle size of the steroid is sis &lt;m hwA ^S1-^{DCe CO}n^{1Se Particles wil1} not Pass through 1 ° hypodermic needle and in the ca»e „r „ fh , .^abeenA'A tlA ^{CaUSe irritation of} the ey_e^P It has been found that, proper particle size is achieved in an oral preparation when the majority-of the particles of the. composition are within the range of about five to preferaffiv^Cffiteen^{and pareateial} °^Γ °Phthalmic use, prererably fifteen microns or less- in size the SSjff ft ^£d °f the selected hydrophilic polyvinyl compound ^hfch has been dried and sterilized is mixed with at least o n? Percent of a sterilized and dried steroid which is sub1 c to crystal growth. The composition can exist in the form of a dried admixture for the extemporaneous prep aration of an aqueous fluid. In the dry form the nrod ρ“Χο71£'” ·τ^η“ ^C ί» ”°^d «' Swy’X χ·„~χ ™ g-ps xsrxx for the preparation thereof but are not to be ^{P e}in any way as: hmiting the invention: thereto.

a lubri- ₂₅

Grams -------------- 50 ------------- 25 ----------- 0.2 ------------- 1 ——------- 4 quantity to adjust

Grams -. 20 - 9 - 0.2 q. s.

EXAMPLE1

A vehicle containing the following ingredients:

Polyvinylpyrrolidone d-Sorbitol-crystalline_______ “Quatresin”_______;____ '

Sodium citrate

Sodium chloride

N/10 NaGH solution in sufficient pH between 6.8 and 7.5, q. _s.

Deionized water, q. s. 1000 cc.

is mixed and filter sterilized. The vehicle is then SdraSAwchT^J^ ^{25 8ramS of Cortisone aceta} S Of -⁰ “^iZeA° Λ passed through a sterile colloid mill, bottled a”?sealed 68 ΪΤ7^P?and AT—^{6 SUSpension} °^{f a} PH between 0 54 Her. ^and ·^{a freez,ng} point depression of about perffid 0^Sf rime^e0R^erade· ^f°^r “ Stemfed

Period of time 98 percent of the particles are less than thanXt^micronl^{1116 remaining two} Percent are less

EXAMPLES

A vehicle containing the following ingredients:

Polyvinyl pyrrolidone

Sodium chloride “Quatresin” iXlSXiXi, * “&gt;« »»£ £ Χϊ “^d SSsSS month period ^{eVen storage 3}

EXAMPLE 3

Following the procedure described in Examnfe 9 «

EXAMPLE 4

A vehicle containing the following ingredients:

Polyvinyl pyrrolidone _ Grams

Dextrose__1

Neomycin sulfate' ZZZZZZ --Sodium citrate ' “Quatresin” _4-5

Deionized water, q.s. 1000 cc.“ θ ,«™^{e v}?^ic,e &gt; *^c™hydrate which has been fi ^{g am}J ^of cortisone acetate particle size‘of less ffianten ·^{ά micronized} * a

ESS=S= rne use of neomycin sulfate in ίγα»ηηΐ_Λ a · .,, “*· on.y construed

2,861,920 be used such as, for example, neomycin base, neomycin hydrochloride, neomycin citrate, and the like, to achiev ^imfiarly^other antibiotics such as bacitracin, chloramphenicol, erythromycin, penicillins such as, penicillin , penicillin G, procaine penicillin, and the like, oxytetr cycline, chlortetracycline, tetracycline, circulm, endomycin, streptomycin, dihydrostreptomycm,

Tnd the like, can also be used to form compositio^, either in dry form or in suspension, suitable for therapeutic use.

EXAMPLE 5

A vehicle containing the following ingredients.

Grams

700

Polyvinyl alcohol-----------Soluble saccharin-----------Sucrose-------------------Benzoic acid--------------Methylparaben------------Deionized water, q. s. 1000 cc.

is mixed To the resulting solution is added fifty grams of cocoa, five grams of micronized progesterone, (particle size less than ten microns) and 0.1.cubic ®®°¹¹”®ξ®^Γimitation black walnut flavor. The product contains particles less than ten microns in size and. is characterized by a pleasant chocolate-nut flavor making it especially suitable for oral use.

EXAMPLE 6

A vehicle containing the following ingredients:

Grams

0.2

Polyvinyl pyrrolidone-------------------------Sodium chloride-----------------------------“Quatresin”------------------N/10 NaOH to adjust pH between 7.0 and 7.5, q. s. Deionized water, q. s., 1000 cc.

is mixed and filter sterilized. The vehicle is then combined aseptically with 25 grams of cortisone acetate hydrate which has been sterilized and micromzed„to a particle size of less than ten microns. The mixture is passed through a sterile colloid mill, bottled and sealed. The sterile suspension thus obtained has a.pH ^e ^®®“ 7 and 7.5, is isotonic and can pass through a 26 _oauge (or finer) hypodermic needle.

example 7

Following the procedure described in Example 6 except for the substitution of cortisone acetate hydrate ^bY hydrocortisone acetate, a sterile suspension of hydrocortisone acetate is obtained which is suitable for therapeutic use. There is no evidence of growth in particle size in mis suspension even after storage for a prolonged period of time.

EXAMPLE 8

A vehicle containing the following ingredients

Polyvinyl pyrrolidone —-----------------------d-Sorbitol-crystalline--------------------------“Quatresin”---------------------------------Sodium citrate-------------------------------Sodium chloride---------------------------------N/10 NaOH solution in sufficient quantity to adjust pH between 6.8 and 7.5, q. s. Deionized water, q. s., 1000 cc.

is mixed and filter sterilized. The vehicle is then combined aseptically with 25 grams of estradiol monobenzoate which has been sterilized and micronized to a particle size of less than ten microns. The mixture is then passed through a sterile colloid mill, bottled and sealed. The final product is a sterile suspension with a pH between 6.8 and 7.5.

Grams ___ 1 ___0.2 ___ 1 ___ 4

EXAMPLE 9

A vehicle containing the following ingredients:

Grams

700

Polyvinyl alcohol------------Soluble saccharin ------------Sucrose--------------------Benzoic acid----------------Methylparaben-------------Deionized water, q. s., 1000 cc.

is mixed. To the resulting mixture is added .fifty grams of cocoa, five grams of micronized ^cortlson® acetate (particle size less than ten microns) and 0.1 cubic centimeter of imitation black walnut, flavor. Th ¹⁵ product contains particles less than ten microns m si and is especially suitable for oral use. example 10

A vehicle containing the following ingredients. Grams ___ 25 ___ 6 ___4.5 ___0.2

Polyvinyl pyrrolidone--------Dextrose ------------------Neomycin sulfate-----------25 Sodium citrate-------------“Quatresin”----------------Deionized water, q. s., 1000 cc.

is mixed and filter sterilized. The vehicle is then combined aseptically with 25 grams of estradiol mono30 benzoate which has been sterilized and micronized to a particle size of less than ten microns.· The mixture is passed through a sterile colloid mill, bottled and sealed. The final product is a sterile suspension of a pH between 7 and 7.5. The product is useful for topical application.

After storage for an extended period of time, the suspension is free of crystal growth. .

The use of neomycin sulfate in this example is illustrative only since other neomycin derivatives can also be used such as, for example, neomycin base, neomycin 4° hydrochloride, neomycin citrate, and the like, to achieve similar results. ,

Similarly, other antibiotics such as bacitracin, chloramphenicol, erythromycin, penicillins such as penicillin O penicillin G, procaine penicillin, and the like, oxy45 tetracycline, chlortetracycline, tetracycline, circulm, endomycin, streptomycin, dihydrostreptomycm, polymyxin and the like, can also be used to form compositions, either in dry form or in suspension, suitable for therapeutic use.

EXAMPLE 11

A vehicle containing the following ingredients:

Grams

0.1 0.2

Polyvinyl pyrrolidone--------⁵⁵ Sodium citrate--------------“Merthiolate” --------------“Quatresin”----------------Chlorobutanol --------------Sodium chloride------------θθ Deionized water, q. s., 1000 cc.

is mixed and filter sterilized. The vehicle is then combined aseptically with 25 grams of cortisone acetate which has been sterilized and micronized to a particle size of 65 less than ten microns. The mixture is passed through a sterile colloid mill, bottled and sealed. The final product is a sterile suspension of a pH between 7 and 7.5 and a freezing point depression of 0.66 degree Centigrade. Crystal growth is greatly retarded after storage for a 70 prolonged period of time.

EXAMPLE 12

Following the procedure described in Example 11 except for the inclusion in the vehicle of six grams of 75 neomycin sulfate, a sterile, stable suspension of neomycin

2,861,920

250

1000

A ⁹ obt^dnZ^1S°^{ne aCetate Suitable for thera}Peutic use is UUlcllElCQ.

EXAMPLE 13

The following ingredients: Polyvinyl alcohol_________

Polyvinyl pyrrolidone______~~~~~~ J

Crystalline d-sorbitol_________ ^g “

Bacitracin________ “ ·, “Quatresin”_____umts__

Cortisone acetate_________ΞΞΞ-ΞΞΞ are intimately combined in the form of a fine powder (or suitably milled together) and placed in a vial On ^cent™eters of water and shaking for

Ss * ^{y a} non-irritating suspension reeven ΓίΪΛΓ . Γ ^{aS a nosedro}P Preparation even after storage for prolonged periods of time, limit λ ° λ ^understod An* the invention is not to be mited to the exact details of operation or exact compositions shown and described herein as obvious modiin tZ¹™¹®¹¹·^{8 WiU be apparent t0} °“^{e ski}««l hv tl⁶ J f “^{ventlon 18} therefore to be limited only by the scope of the appended claims.