Patent Publication Number: US-2023145274-A1

Title: Adhesive matrix with hydrophilic and hydrophobic domains and a therapeutic agent

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 16/312,252, filed Dec. 20, 2018, now allowed, which was filed under 35 U.S.C. § 371 of International Application No. PCT/US2017/038934, with an International Filing Date of Jun. 23, 2017, which claims priority to U.S. Provisional Application No. 62/353,891, filed Jun. 23, 2016, each of which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The subject matter described herein relates to transdermal administration of drugs for both local and systemic delivery, and formulations for use in such methods. 
     BACKGROUND 
     The delivery of drugs through the skin provides many advantages; primarily, such a means of delivery is a comfortable, convenient and noninvasive way of administering drugs. The variable rates of absorption and metabolism encountered in oral treatment are avoided, and other inherent inconveniences—e.g., gastrointestinal irritation and the like—are eliminated as well. Transdermal drug delivery also makes possible a high degree of control over blood concentrations of any particular drug. 
     The skin is the largest organ of the human body. It is easily accessible, has an excellent blood supply, and presents an ideal location to administer therapeutic agents. However, the primary function of the skin is to act as a permoselective barrier, inhibiting the penetration of molecules and unwanted compounds into the body, thereby making drug delivery via the skin difficult. Strategies designed to overcome the barrier properties of the skin include the use of chemical penetration enhancers, supersaturation, and altering the integrity of the skin, for example by electrophoresis or iontophoresis. Chemical penetration enhancers work by increasing the solubility of a drug in the skin, enhancing partitioning and hence permeation. Supersaturation of a therapeutic agent in a transdermal system increases the thermodynamic activity of the agent to thereby enhance permeation rate. When a drug is saturated in a vehicle, the thermodynamic activity is equal to one (i.e., unity). Since drug thermodynamic activity is proportional to drug permeation rate, increasing the thermodynamic activity should increase permeation rate. However, supersaturated formulations are physically unstable and, over time, the drug in a supersaturated solution will precipitate, and this loss of drug from solution will eventually result in a return to a more stable saturated state. Accordingly, to date, this approach has found limited applicability in practice. 
     BRIEF SUMMARY 
     The following aspects and embodiments thereof described and illustrated below are meant to be exemplary and illustrative, not limiting in scope. 
     In one aspect, an adhesive matrix comprised of a hydrophilic domain and a hydrophobic domain, and a therapeutically active agent contained therein in a supersaturated condition, is provided. The hydrophilic domain is comprised of a polyvinylpyrrolidone-vinyl acetate copolymer and the hydrophobic domain comprises one or both of a polyisobutylene and an acrylic acid/vinyl acetate copolymer. The active agent is characterized by (a) a melting point of less than about 250° C. or (b) a solubility in water of less than about 500 mg/L or (c) an oil/water partition coefficient of between about 2.1 and about 5. The hydrophilic domain and the hydrophobic domain are co-soluble in a solvent system and the proportion of the hydrophilic domain and hydrophobic domain is selected to optimize, or maximize, solubility of active agent in the matrix. In one embodiment, the matrix comprises an amount of active agent greater than the amount of active agent soluble in either domain alone. In another embodiment, the matrix comprises an amount of active agent greater than the amount of active agent soluble in the hydrophobic domain alone. In another embodiment, the matrix comprises an amount of active agent greater than the amount of active agent soluble in the hydrophilic domain alone. 
     In one embodiment, the hydrophobic domain comprises a combination of polyisobutylene and polybutene. In another embodiment, the hydrophobic domain comprises an acrylic acid/vinyl acetate copolymer. 
     In another embodiment, the adhesive matrix comprises between about 10-25 wt % hydrophilic domain. In still another embodiment, the adhesive matrix comprises between about 35-80 wt % hydrophobic domain. 
     In still another embodiment, the adhesive matrix comprises about 15-25 wt % active agent, about 50-60 wt % acrylate adhesive, about 7-15 wt % polyisobutylene and polybutene mixture, and about 10-20 wt % polyvinylpyrrolidone-vinyl acetate copolymer. 
     In yet another embodiment, the active agent is selected from the group of drugs consisting of donepezil, ropinrole, lidocaine, and oxybutynin. 
     In another aspect, a device for transdermal administration of an active agent is provided, where the device comprises an adhesive matrix layer as described herein. 
     In still another aspect, a formulation for preparation of an adhesive matrix is provided. The formulation, in one embodiment, comprises between about 10-25 wt % polyvinylpyrrolidone-vinyl acetate copolymer and between about 40-64 wt % of an acrylate adhesive, and about 5-50 wt % of an active agent in a solvent system. The solvent system, in one embodiment, comprises an organic solvent in which the polyvinylpyrrolidone-vinyl acetate copolymer is soluble and in which a polyvinylpyrrolidone homopolymer is insoluble. 
     In one embodiment, the formulation additionally comprises about 35-75 wt % of polyisobutylene and polybutene. In this embodiment, the solvent system comprises a solvent in which the polyisobutylene and polybutene and the polyvinylpyrrolidone-vinyl acetate copolymer are soluble. 
     In another aspect, a method for the manufacture of an adhesive matrix is provided. In one embodiment, the method comprises solubilizing a polyvinylpyrrolidone-vinyl acetate copolymer in a first solvent; solubilizing polyisobutylene and polybutene in a second solvent; mixing the two to form a homogeneous solution; adding to the homogeneous solution an acrylate adhesive solubilized in a third solvent to form an adhesive solution; adding to the adhesive solution an active agent; and forming an adhesive matrix from the adhesive solution with active agent. 
     In another embodiment, the method comprises solubilizing a polyvinylpyrrolidone-vinyl acetate copolymer in a first solvent; solubilizing an acrylate adhesive in a second solvent; mixing the two to form an adhesive solution; adding to the adhesive solution an active agent; and forming an adhesive matrix from the adhesive solution with active agent. 
     In one embodiment, the acrylate adhesive is not a methacrylate copolymer. 
     In another embodiment, the polyvinylpyrrolidone-vinyl acetate copolymer is a copolymer of n-vinyl-2-pyrrolidone and a vinyl acetate that is not ethylhexyl acrylate. That is, the acrylate is not 2-ethylhexyl acrylate-vinyl pyrrolidone copolymer. 
     In one embodiment, the polyvinylpyrrolidone-vinyl acetate copolymer is a linear random copolymer of n-vinyl-2-pyrrolidone and vinyl acetate. In one embodiment, the copolymer is a 60:40 copolymer of n-vinyl-2-pyrrolidone and vinyl acetate. In still another embodiment, the acrylate adhesive is an acrylic acid/vinyl acetate copolymer, excluding methacrylic acid/vinyl acetate copolymers. 
     In yet another embodiment, the acrylic acid/vinyl acetate copolymer is one without a cross-linker agent and has a viscosity between about 2000-8000 mPa-s when measured at 25° C. 
     In one embodiment, the first solvent is one in which polyvinylpyrrolidone homopolymer is insoluble. For example, and in one embodiment, the first solvent comprises toluene. In another embodiment, the first solvent comprises a mixture of toluene and iso-propyl alcohol. In one embodiment, the mixture comprises 9 parts toluene and 1 part iso-propyl alcohol, w/w. In another embodiment, the mixture comprises 9 parts toluene and 1 part iso-propyl alcohol, v/v. 
     In another embodiment, the second solvent is the same as the first solvent. In still another embodiment, the first solvent is a mixture comprising toluene and the second solvent is toluene. 
     In one embodiment, the solvent for the acrylate adhesive, sometimes referred to as a second solvent or as a third solvent, is ethyl acetate. 
     In one embodiment, forming an adhesive matrix comprises applying the adhesive solution with the active agent onto a substrate and drying at a temperature of between 50-100° C. 
     In another embodiment, the adhesive matrix comprises 15-25 wt % active agent, 50-60 wt % acrylate adhesive, 7-15 wt % polyisobutylene and polybutene mixture and 10-20 wt % polyvinylpyrrolidone-vinyl acetate copolymer. 
     The matrix, formulation and method can comprise as an active agent a drug selected from the group consisting of donepezil, ropinrole, lidocaine, and oxybutynin. 
     In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the examples and by study of the following descriptions. 
     Additional embodiments of the present methods and compositions, and the like, will be apparent from the following description, examples, and claims. As can be appreciated from the foregoing and following description, each and every feature described herein, and each and every combination of two or more of such features, is included within the scope of the present disclosure provided that the features included in such a combination are not mutually inconsistent. In addition, any feature or combination of features may be specifically excluded from any embodiment of the present invention. Additional aspects and advantages of the present invention are set forth in the following description and claims, particularly when considered in conjunction with the accompanying examples. 
    
    
     DETAILED DESCRIPTION 
     I. Definitions 
     Various aspects now will be described more fully hereinafter. Such aspects may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. 
     Where a range of values is provided, it is intended that each intervening value between the upper and lower limit of that range and any other stated or intervening value in that stated range is encompassed within the disclosure. For example, if a range of 1 μm to 8 μm is stated, it is intended that 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, and 7 μm are also explicitly disclosed, as well as the range of values greater than or equal to 1 μm and the range of values less than or equal to 8 μm. 
     The singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a “polymer” includes a single polymer as well as two or more of the same or different polymers, reference to an “excipient” includes a single excipient as well as two or more of the same or different excipients, and the like. 
     II. ADHESIVE FORMULATION AND ADHESIVE MATRIX 
     The adhesive matrix described herein is comprised of a hydrophilic domain and a hydrophobic domain, and a therapeutically active agent contained in the matrix in a supersaturated, stable, condition. The hydrophilic domain and the hydrophobic domain are co-soluble in a solvent system, to provide a homogeneous blend in which the active agent is solubilized. The proportion of the hydrophilic domain and hydrophobic domain is selected to optimize, or maximize, solubility of active agent in the matrix. For example, and in one embodiment, the matrix comprises an amount of active agent greater than the amount of active agent soluble in the hydrophobic domain alone or, in another embodiment, the hydrophilic domain alone, or, in yet another embodiment, in both domains alone. In one embodiment, the amount of active agent in the matrix is about the saturation concentration of the active agent in the hydrophobic domain alone or, in another embodiment, the hydrophilic domain alone, or, in yet another embodiment, in both domains alone. 
     The hydrophilic domain is comprised of a polyvinylpyrrolidone-vinyl acetate copolymer and the hydrophobic domain comprises one or both of a polyisobutylene and an acrylic acid/vinyl acetate copolymer. 
     Polyvinylpyrrolidone-vinyl acetate copolymers are linear, random copolymers produced by the free-radical polymerization of the monomers N-vinyl-2-pyrrolidone (NVP) and vinyl acetate (VA). The amount of each monomer can be varied to product copolymers with ratios varying from 70/30 to 30/70 vinyl acetate to vinylpyrrolidone. In one embodiment, the copolymer comprises 30% vinylpyrrolidone; in another embodiment, the copolymer comprises 50% vinylpyrrolidone content; in another embodiment, the copolymer comprises 60% vinylpyrrolidone content; and in another embodiment, the copolymer comprises 70% vinylpyrrolidone content. In one embodiment, the polyvinylpyrrolidone-vinyl acetate copolymer results from polymerization of an n-vinyl-2-pyrrolidone monomer and a vinyl acetate monomer that is not ethylhexyl acrylate. 
     The molecular weight of polyvinylpyrrolidone-vinyl acetate copolymers may vary, and copolymers in a range of molecular weights are commercially available. In one embodiment, a polyvinylpyrrolidone-vinyl acetate copolymer with a molecular weight (weight average) is between 40,000-60,000 Daltons, and in another embodiment, is between about 25,000-200,000 Daltons. 
     In the working examples set forth hereinbelow, a polyvinylpyrrolidone-vinyl acetate copolymer comprised of 60% vinylpyrrolidone content and a weight average molecular weight of 47,000 Daltons was used. 
     The hydrophobic domain in the adhesive matrix comprises one or both of a polyisobutylene and an acrylic acid/vinyl acetate copolymer. In another embodiment, the hydrophobic domain in the adhesive matrix comprises an acrylic acid/vinyl acetate copolymer, and optionally, a polyisobutylene. 
     In one embodiment, a polyisobutylene is a blend or a mixture of a high molecular weight polyisobutylene and a medium molecular weight polyisobutylene. The term. “high molecular weight polyisobutylene” refers to a polyisobutylene having an average molecular weight in the range of about 450,000 to about 2,100,000 Daltons, and preferably from about 500,000 to about 1,500,000 Daltons. The term, “medium molecular weight polyisobutylene” refers to a polyisobutylene having an average molecular weight in the range of about 10,000 to about 450,000 Daltons, and preferably from about 25,000 to about 100,000 Daltons, 
     In the working examples set forth hereinbelow, a high molecular weight polyisobutylene of 1,000,000 Daltons and a medium molecular weight polyisobutylene of about 50,000 Daltons were blended in a ratio of 1:5. Stated alternatively, on a 100 weight basis, the matrix comprised a ratio of high molecular weight polyisobutylene to medium molecular weight polyisobutylene of 17:83. In other embodiments, the adhesive matrix contains a high molecular weight polyisobutylene to medium molecular weight polyisobutylene ratio of between about 5-40:95-60, or between about about 10-25:90-75 or between about 10-20:90-80. 
     In another embodiment, the polyisobutylene (also referred to as a polyisobutylenen blend) in the hydrophobic domain further comprises a polybutene. Polybutene is a viscous, non-drying, liquid polymer, prepared by the copolymerization of 1- and 2-butene with a small quantity of isobutylene. The polybutene in one embodiment has a molecular weight of between about 750-6000 Daltons, preferably between about 900-4000 Daltons, and preferably between about 900-3000 Daltons. In the working examples below, some embodiments of the hydrophobic domain comprised a polybutene of 2500 Dalton molecular weight, present in the polyisobutylene blend at 40 weight percent. More generally, the polybutene is present in the polyisobutylene blend of the hydrophobic domain in an amount between 20-50 weight percent, or between 25-45 weight percent. 
     The hydrophobic domain of the adhesive matrix comprises an acrylic polymer pressure sensitive adhesive. An acrylic polymer pressure sensitive adhesive intends a polyacrylate adhesive that is a polymer or a copolymer of a monomer or monomers selected from acrylic acid esters and methacrylic acid esters. Other monomers, such as acrylic acid and vinyl acetate, may be present. In one embodiment, the acrylate adhesive is not a methacrylate copolymer; that is, the polyacrylate adhesive excludes a methacrylic acid monomeric unit. Preferably the acrylic polymer pressure sensitive adhesive has pendent carboxyl (—COOH) or hydroxyl (—OH) functional groups attached to the polymer chain. 
     In one embodiment, the acrylic acid/vinyl acetate copolymer is one without a cross-linker agent. The exclusion of cross-linker agents containing metals, particularly transition metal cross-linking agents, which act as catalysts of several chemical reactions, such as esterification, transesterification, oxidation and addition, avoids the possibility of chemical interaction with the active agent in the matrix and a possible loss of potency, impurity formation and stability problems. Preferably the adhesive matrix layer contains no component acting as a cross-linking agent for the acrylic polymer. 
     In one embodiment, the acrylic acid/vinyl acetate copolymer has a viscosity between about 2000-8000 mPa-s when measured at 25° C. 
     The adhesive matrix can include additives and excipients as is common in the art. By way of example, the matrix can include penetration enhancers such as fatty acids having a carbon number of 6-20, aliphatic alcohols, fatty acid esters or ethers or amides, aromatic organic acids, aromatic alcohols, aromatic organic acid esters or ethers (saturated or unsaturated, and either cyclic, straight chain or branched), furthermore, lactic acid esters, acetic acid esters, monoterpene compounds, sesquiterpene compounds, Azone, Azone derivatives, glycerin fatty acid esters, sorbitan fatty acid esters, polyethylene glycol fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene hardened castor oil (HCO), sucrose fatty acid esters and the like. Fatty acids having a carbon number of 8 or more (such as caprylic acid, capric acid, myristic acid, palmitic acid, oleic acid, stearic acid, etc.), and aliphatic alcohols (such as oleyl alcohol, isostearyl alcohol, lauryl alcohol, octyl alcohol, decyl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, etc.) are contemplated. The amount of enhancer is, taking into consideration the sufficient permeability of active components into the skin and skin irritation as adhesive patches, between about 1-10 wt %, or about 2-8 wt %, and or about 3-6 wt % relative to the weight of the adhesive matrix. 
     Additives such as antioxidants, fillers, preservatives and ultraviolet absorbers may be blended in the adhesive matrix. As antioxidants, tocopherol and its ester derivatives, ascorbic acid, ascorbic acid-stearic acid ester, nordihydroguaretic acid, dibutyl hydroxy toluene (BHT), butyl hydroxy anisole and the like are preferred. As fillers, calcium carbonate, magnesium carbonate, silicates (such as aluminum silicate, magnesium silicate, etc.), silicic acid, barium sulfate, calcium sulfate, calcium zincate, zinc oxide, titanium oxide and the like are preferred. As preservatives, ethyl p-hydroxybenzoate, propyl p-hydroxybenzoate, butyl p-hydroxybenzoate and the like are preferred. As ultraviolet absorbers, p-aminobenzoic acid derivatives, anthranilic acid derivatives, salicylic acid derivatives, coumarin derivatives, amino-acid compounds, imidazoline derivatives, pyrimidine derivatives, dioxane derivatives and the like are preferred. These additives may be present in the adhesive matrix at an amount of preferably 10 wt % or less, more preferably 5 wt % or less, and especially preferably 2 wt % or less. 
     The adhesive matrix also comprises a therapeutically active agent. The active agent is characterized by (a) a melting point of less than about 250° C. or (b) a solubility in water of less than about 500 mg/L or (c) an oil/water partition coefficient of between about 2.1 and about 5. Examples of active agents are set forth in the table below, and include donepezil, ropinrole, lidocaine, and oxybutynin. 
     
       
         
           
               
               
               
               
             
               
                   
               
               
                 Active Agent 
                   
                 Melting Point 
                   
               
               
                 (base) 
                 Water solubility 
                 (° C/) 
                 LogP 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 donepezil 
                 2.931 mg/L 
                 206.7 
                 4.86 
               
               
                   
                 (pubchem.ncbi.nlm.nih.gov) 
                   
                   
               
               
                 ropinole 
                   133 mg/mL 
                 243-250 
                 2.7 
               
               
                 lidocaine 
                 410 mg/L at 30 C. 
                 68 
                 2.26 
               
               
                 oxybutynin 
                 10 mg/L (drugbank.ca) 
                 129-130 
                 4.3 
               
               
                   
               
            
           
         
       
     
     Adhesive formulations and matrices were prepared to illustrate the concepts described above. Examples 1-10 set forth exemplary formulations and resulting adhesive matrices using the active agent donezepil, in its base form, as a model drug. 
     In Example 1, an adhesive matrix comprising 66 wt % of a hydrophobic domain and 14% of a hydrophilic domain was prepared, with the active agent present at 20 wt % in the matrix. The active agent was present at a concentration above its saturation concentration in the hydrophobic domain alone, due to the presence of the hydrophilic domain, which lowered the solublity of the hydrophobic domain for the active agent. Accordingly, the active agent was present in the adhesive matrix at a supersaturated concentration, to thereby provide a thermodynamic activity greater than unity to provide a maximum driving force for permeation of the agent across the skin. The hydrophobic domain in the exemplary adhesive matrix of Example 1 was comprised of a homogeneous blend of an acrylic acid/vinyl acetate copolymer and a polyisobutylene mixture of a high molecular weight polyisobutylene, a medium molecular weight polyisobutylene, and a polybutene. The blend had 86 parts of the acrylic acid/vinyl acetate copolymer and 14 parts of polyisobutylene mixture. 
     In Example 2, an adhesive matrix comprising 62 wt % of a hydrophobic domain and 13% of a hydrophilic domain was prepared, with the active agent present at 20 wt % in the matrix. The active agent was present at a concentration above its saturation concentration in the hydrophobic domain alone, due to the presence of the hydrophilic domain, which lowered the solublity of the hydrophobic domain for the active agent. Accordingly, the active agent was present in the adhesive matrix at a supersaturated concentration, to thereby provide a thermodynamic activity greater than unity to provide a maximum driving force for permeation of the agent across the skin. The hydrophobic domain in the exemplary adhesive matrix of Example 2 was comprised of a homogeneous blend of an acrylic acid/vinyl acetate copolymer and a polyisobutylene mixture of a high molecular weight polyisobutylene, a medium molecular weight polyisobutylene, and a polybutene. The blend had 93 parts of the acrylic acid/vinyl acetate copolymer and 7 parts of polyisobutylene mixture. The adhesive matrix additionally included a penetration enhancer. 
     In Example 3, an adhesive matrix comprising 62 wt % of a hydrophobic domain and 13% of a hydrophilic domain was prepared, with the active agent present at 20 wt % in the matrix. The hydrophobic domain in the exemplary adhesive matrix of Example 3 was comprised of a homogeneous blend of an acrylic acid/vinyl acetate copolymer and a polyisobutylene mixture of a high molecular weight polyisobutylene, a medium molecular weight polyisobutylene, and a polybutene. The blend had 85 parts of the acrylic acid/vinyl acetate copolymer and 15 parts of polyisobutylene mixture. The adhesive matrix additionally included a penetration enhancer. 
     In Example 4, an adhesive matrix comprising 62 wt % of a hydrophobic domain and 5 wt % of a hydrophilic domain was prepared, with the active agent present at 20 wt % in the matrix. The hydrophobic domain in the exemplary adhesive matrix of Example 4 was comprised of a homogeneous blend of an acrylic acid/vinyl acetate copolymer and a polyisobutylene mixture of a high molecular weight polyisobutylene, a medium molecular weight polyisobutylene, and a polybutene. The blend had 79 parts of the acrylic acid/vinyl acetate copolymer and 21 parts of polyisobutylene mixture. The adhesive matrix additionally included a penetration enhancer. 
     In Example 5, an adhesive matrix comprising 57 wt % of a hydrophobic domain and 13 wt % of a hydrophilic domain was prepared, with the active agent present at 20 wt % in the matrix. The hydrophobic domain in the exemplary adhesive matrix of Example 5 was comprised of a homogeneous blend of an acrylic acid/vinyl acetate copolymer and a polyisobutylene mixture of a high molecular weight polyisobutylene, a medium molecular weight polyisobutylene, and a polybutene. The blend had 77 parts of the acrylic acid/vinyl acetate copolymer (44/57) and 22 parts (13/57) of polyisobutylene mixture. The adhesive matrix additionally included a penetration enhancer. 
     In Example 6, an adhesive matrix comprising 45 wt % of a hydrophobic domain and 15 wt % of a hydrophilic domain was prepared, with the active agent present at 40 wt % in the matrix. The hydrophobic domain in the exemplary adhesive matrix of Example 6 was comprised of an acrylic acid/vinyl acetate copolymer. 
     In Example 7, an adhesive matrix comprising 42 wt % of a hydrophobic domain and 14 wt % of a hydrophilic domain was prepared, with the active agent present at 40 wt % in the matrix. The hydrophobic domain in the exemplary adhesive matrix of Example 7 was comprised of an acrylic acid/vinyl acetate copolymer. The adhesive matrix additionally included a penetration enhancer. 
     In Examples 8-10, adhesive matrices comprised of a hydrophobic domain and a hydrophilic domain of a polyvinylpyrrolidone homopolymer are set forth. 
     The table below summarizes the weight ratios of the hydrophobic domain to hydrophilic domain in the exemplary adhesive matrices of Examples 1-10, and also shows the ratio of drug to hydrophobic domain. 
     
       
         
           
               
               
               
             
               
                   
               
               
                   
                 Ratio Hydrophobic 
                 Ratio 
               
               
                 Example 
                 Domain/Hydrophilic 
                 Drug/Hydrophobic 
               
               
                 No. 
                 Domain 
                 Domain 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 1 
                 4.67 
                 3.29 
               
               
                 2 
                 4.68 
                 3.09 
               
               
                 3 
                 4.77 
                 3.1 
               
               
                 4 
                 12.4 
                 3.1 
               
               
                 5 
                 4.38 
                 2.85 
               
               
                 6 
                 3.0 
                 1.12 
               
               
                 7 
                 3.0 
                 1.05 
               
               
                 8 
                 6.37 
                 1.28 
               
               
                 9 
                 6.4 
                 2.59 
               
               
                 10 
                 6.39 
                 4.90 
               
               
                   
               
            
           
         
       
     
     Preparation of Adhesive Matrix and Transdermal Device 
     In another aspect, a formulation for preparation of an adhesive matrix is provided. The formulation comprises, in one embodiment, between about 10-25 wt % polyvinylpyrrolidone-vinyl acetate copolymer and about 40-64 wt % of an acrylate adhesive and about 5-50 wt % of an active agent in a solvent system. In one embodiment, the solvent system is comprised of an organic solvent in which the polyvinylpyrrolidone-vinyl acetate copolymer is soluble and a polyvinylpyrrolidone homopolymer is insoluble. In one embodiment, the solvent system is a binary mixture of organic solvents, and in another embodiment, is a ternary mixture. 
     A method for the manufacture of an adhesive matrix is also provided. With reference to Example 1, the method comprises (i) solubilizing a polyvinylpyrrolidone-vinyl acetate copolymer in a first solvent; (ii) solubilizing polyisobutylene and polybutene (when present in the formulation) in a second solvent; (iii) mixing (i) and (ii) to form a homogeneous solution; (iv) adding to the homogeneous solution an acrylate adhesive solubilized in a third solvent to form an adhesive solution; (v) adding to the adhesive solution an active agent as described herein, and (v) forming an adhesive matrix from the adhesive solution with the active agent that comprises between about 35-80 wt % acrylate, between about 0.01-30 wt % polyisobutylene and polybutene mixture, between about 10-25 wt % polyvinylpyrrolidone-vinyl acetate copolymer, and between about 5-50 wt % active agent. 
     In another embodiment, the method comprises (i) solubilizing a polyvinylpyrrolidone-vinyl acetate copolymer in a first solvent; (ii) solubilizing an acrylate adhesive in a second solvent; (iii) mixing (i) and (ii) to form a homogeneous solution; (iv) adding to the homogeneous solution an active agent as described herein, and (v) forming an adhesive matrix from the solution of (iv). In one embodiment, the adhesive matrix formed from the solution comprises between about 35-80 wt % acrylate, between about 10-25 wt % polyvinylpyrrolidone-vinyl acetate copolymer, and between about 5-50 wt % active agent. 
     In forming the adhesive matrix, the formulation is cast onto a suitable film, such as a release liner film, dried to eliminate all volatile compounds at temperature or temperatures in the range between 50° C. and 100° C. 
     To form a transdermal device, the adhesive matrix is then laminated to a suitable film, generally to a backing film. Backing films are known in the industry and any that provide support for the adhesive layer and are impermeable or substantially impermeable to the active agent can be used. It can be flexible or nonflexible. Suitable materials are well known to the art and include, without limitation, polyethylene terephthalate, various nylons. polypropylene, metalized polyester films, polyvinylidene chloride, and aluminum foil. In other embodiments, the transdermal device may comprise a fabric or tie layer in the adhesive matrix, and any stretch or nonstretch material may be used. For example, fabric and non-woven fabric material including polyesters such as polyethylene terephthalate, polyurethane, polyvinyl acetate, polyvinylidene chloride and polyethylene, may be used. 
     III. EXAMPLES 
     The following examples are illustrative in nature and are in no way intended to be limiting. 
     Example 1 
     Adhesive Formulation, Adhesive Matrix and Transdermal Devices Comprising Donepezil 
     A formulation for a hydrophilic domain was prepared by dissolving a polyvinylpyrrolidone vinyl acetate copolymer (Plasdone S-630) in a 9:1 mixture of toluene and isopropyl alcohol to yield a solution with 35 wt % polyvinylpyrrolidone vinyl acetate copolymer. A formulation for a hydrophobic domain was prepared by dissolving a blend of a high molecular weight polyisobutylene homopolymer (Oppanol B-100; 1,000,000 Dalton molecular weight) and a medium moleculear weight polyisobutylene homopolymer (Oppanol B-12; 50,000 Dalton molecular weight) with polybutene (Indopol H-1900) in a ratio of 1:5:4 in toluene, where the polyisobutylene blend was at a concentration of 60 wt %. 
     An acrylate adhesive solution was prepared by dissolving an acrylic acid/vinyl acetate copolymer (DuroTak 87-2015) in ethyl acetate at a concentration of 51.5 wt %. An adhesive formulation was prepared as follows. 2.017 g of the hydrophilic domain formulation was mixed with 0.784 g of the hydrophobic domain formulation until a homogeneous solution was formed. An additional 2.49 g of toluene and 0.72 g of isopropyl alcohol were added and the solution was well mixed. Next, 5.483 g of the acrylate adhesive solution was added, mixing until homogeneous. Then, 1.00 g of donepezil base was added and dissolved with vortexing. 
     An adhesive matrix was prepared by coating the adhesive formulation onto a silicon-coated release liner at a wet thickness of 20 mils and then drying at 70° C. for 20 minutes. The adhesive matrix had a final composition as follows: 
     
       
         
           
               
             
               
                   
               
               
                 Adhesive Matrix No. 1 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Hydrophobic Domain— 
                 acrylic acid/vinyl acetate copolymer 
                 56.47 wt % 
               
               
                 65.8 wt % 
                 polyisobutylene homopolymer 
                  9.41 wt % 
               
               
                   
                 blend/polybutene 
                   
               
               
                 Hydrophilic Domain— 
                 polyvinylpyrrolidone vinyl acetate 
                 14.12 wt % 
               
               
                 14.1 wt % 
                 copolymer 
                   
               
               
                 Active Agent—20 wt % 
                 donepezil base 
                   20 wt % 
               
               
                   
               
            
           
         
       
     
     A backing layer (Scotchpak 9732) was then laminated onto the matrix and transdermal devices of 10 cm2 were die cut from the laminate. 
     Example 2 
     Adhesive Formulation, Adhesive Matrix and Transdermal Devices Comprising Donepezil 
     An adhesive formulation was prepared as described in Example 1 to yield an adhesive matrix with the following composition: 
     
       
         
           
               
             
               
                   
               
               
                 Adhesive Matrix No. 2 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Hydrophobic Domain— 
                 acrylic acid/vinyl acetate copolymer 
                 57.4 wt % 
               
               
                 61.8 wt % 
                 polyisobutylene homopolymer 
                 4.40 wt % 
               
               
                   
                 blend/polybutene 
                   
               
               
                 Hydrophilic Domain— 
                 polyvinylpyrrolidone vinyl acetate 
                 13.2 wt % 
               
               
                 13.2 wt % 
                 copolymer 
                   
               
               
                 Active Agent—20 wt % 
                 donepezil base 
                 20.0 wt % 
               
               
                 Penetration Enhancer 
                 Lauryl lactate 
                  5.0 wt % 
               
               
                   
               
            
           
         
       
     
     Example 3 
     Adhesive Formulation, Adhesive Matrix and Transdermal Devices Comprising Donepezil 
     An adhesive formulation was prepared as described in Example 1 to yield an adhesive matrix with the following composition: 
     
       
         
           
               
             
               
                   
               
               
                 Adhesive Matrix No. 3 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Hydrophobic Domain— 
                 acrylic acid/vinyl acetate copolymer 
                 53.0 wt % 
               
               
                 62.0 wt % 
                 polyisobutylene homopolymer 
                  9.0 wt % 
               
               
                   
                 blend/polybutene 
                   
               
               
                 Hydrophilic Domain— 
                 polyvinylpyrrolidone vinyl acetate 
                 13.0 wt % 
               
               
                 13.0 wt % 
                 copolymer 
                   
               
               
                 Active Agent—20.0 wt % 
                 donepezil base 
                 20.0 wt % 
               
               
                 Penetration Enhancer 
                 Lauryl lactate 
                  5.0 wt % 
               
               
                   
               
            
           
         
       
     
     Example 4 
     Adhesive Formulation, Adhesive Matrix and Transdermal Devices Comprising Donepezil 
     An adhesive formulation was prepared as described in Example 1 to yield an adhesive matrix with the following composition: 
     
       
         
           
               
             
               
                   
               
               
                 Adhesive Matrix No. 4 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Hydrophobic Domain— 
                 acrylic acid/vinyl acetate copolymer 
                 49.0 wt % 
               
               
                 62.0 wt % 
                 polyisobutylene homopolymer 
                 13.0 wt % 
               
               
                   
                 blend/polybutene 
                   
               
               
                 Hydrophilic Domain— 
                 polyvinylpyrrolidone vinyl acetate 
                  5.0 wt % 
               
               
                 5.0 wt % 
                 copolymer 
                   
               
               
                 Active Agent—20 wt % 
                 donepezil base 
                 20.0 wt % 
               
               
                 Penetration Enhancer 
                 Lauryl lactate 
                  5.0 wt % 
               
               
                   
               
            
           
         
       
     
     Example 5 
     Adhesive Formulation, Adhesive Matrix and Transdermal Devices Comprising Donepezil 
     An adhesive formulation was prepared as described in Example 1 to yield an adhesive matrix with the following composition: 
     
       
         
           
               
             
               
                   
               
               
                 Adhesive Matrix No. 5 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Hydrophobic Domain— 
                 acrylic acid/vinyl acetate copolymer 
                 44.0 wt % 
               
               
                 57.0 wt % 
                 polyisobutylene homopolymer 
                 13.0 wt % 
               
               
                   
                 blend/polybutene 
                   
               
               
                 Hydrophilic Domain— 
                 polyvinylpyrrolidone vinyl acetate 
                 13.0 wt % 
               
               
                 13.0 wt % 
                 copolymer 
                   
               
               
                 Active Agent—wt % 
                 donepezil base 
                 20.0 wt % 
               
               
                 Penetration Enhancer 
                 Lauryl lactate 
                  5.0 wt % 
               
               
                   
               
            
           
         
       
     
     Example 6 
     Adhesive Formulation, Adhesive Matrix and Transdermal Devices Comprising Donepezil 
     An adhesive formulation was prepared as described in Example 1 to yield an adhesive matrix with the following composition: 
     
       
         
           
               
             
               
                   
               
               
                 Adhesive Matrix No. 6 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Hydrophobic Domain— 
                 acrylic acid/vinyl acetate copolymer 
                 45.0 wt % 
               
               
                 45.0 wt % 
                 polyisobutylene homopolymer 
                  0.0 wt % 
               
               
                   
                 blend/polybutene 
                   
               
               
                 Hydrophilic Domain— 
                 polyvinylpyrrolidone vinyl acetate 
                 15.0 wt % 
               
               
                 15.0 wt % 
                 copolymer 
                   
               
               
                 Active Agent— 
                 donepezil base 
                 40.0 wt % 
               
               
                 40.0 wt % 
               
               
                   
               
            
           
         
       
     
     Example 7 
     Adhesive Formulation, Adhesive Matrix and Transdermal Devices Comprising Donepezil 
     An adhesive formulation was prepared as described in Example 1 to yield an adhesive matrix with the following composition: 
     
       
         
           
               
             
               
                   
               
               
                 Adhesive Matrix No. 7 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Hydrophobic Domain— 
                 acrylic acid/vinyl acetate copolymer 
                 42.0 wt % 
               
               
                 42.0 wt % 
                 polyisobutylene homopolymer 
                  0.0 wt % 
               
               
                   
                 blend/polybutene 
                   
               
               
                 Hydrophilic Domain— 
                 polyvinylpyrrolidone vinyl acetate 
                 14.0 wt % 
               
               
                 14.0 wt % 
                 copolymer 
                   
               
               
                 Active Agent—40.0 wt % 
                 donepezil base 
                 40.0 wt % 
               
               
                 Penetration Enhancer 
                 lauryl lactate 
                  4.0 wt % 
               
               
                   
               
            
           
         
       
     
     Example 8 
     Adhesive Formulation, Adhesive Matrix and Transdermal Devices Comprising Donepezil 
     An adhesive formulation was prepared as described in Example 1 to yield an adhesive matrix with the following composition: 
     
       
         
           
               
             
               
                   
               
               
                 Adhesive Matrix No. 8 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Hydrophobic Domain— 
                 acrylic acid/vinyl acetate copolymer 
                 51.61 wt % 
               
               
                 51.6 wt% 
                 polyisobutylene homopolymer 
                  0.0 wt % 
               
               
                   
                 blend/polybutene 
                   
               
               
                 Hydrophilic Domain— 
                 polyvinylpyrrolidone  
                  8.06 wt % 
               
               
                 8.1 wt % 
                 (Kollidone 90K) 
                   
               
               
                 Active Agent— 
                 donepezil base 
                 40.32 wt % 
               
               
                 40.32 wt % 
               
               
                   
               
            
           
         
       
     
     Example 9 
     Adhesive Formulation, Adhesive Matrix and Transdermal Devices Comprising Donepezil 
     An adhesive formulation was prepared as described in Example 1 to yield an adhesive matrix with the following composition: 
     
       
         
           
               
             
               
                   
               
               
                 Adhesive Matrix No. 9 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Hydrophobic Domain— 
                 acrylic acid/vinyl acetate copolymer 
                  64.8 wt % 
               
               
                 64.8 wt % 
                 polyisobutylene homopolymer 
                  0.0 wt % 
               
               
                   
                 blend/polybutene 
                   
               
               
                 Hydrophilic Domain— 
                 polyvinylpyrrolidone  
                 10.14 wt % 
               
               
                 10.1 wt % 
                 (Kollidone 90K) 
                   
               
               
                 Active Agent—25 wt % 
                 donepezil base 
                  25.0 wt % 
               
               
                   
               
            
           
         
       
     
     Example 10 
     Adhesive Formulation, Adhesive Matrix and Transdermal Devices Comprising Donepezil 
     An adhesive formulation was prepared as described in Example 1 to yield an adhesive matrix with the following composition: 
     
       
         
           
               
             
               
                   
               
               
                 Adhesive Matrix No. 10 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Hydrophobic Domain— 
                 acrylic acid/vinyl acetate copolymer 
                 73.51 wt % 
               
               
                 73.5 wt % 
                 polyisobutylene homopolymer 
                  0.0 wt % 
               
               
                   
                 blend/polybutene 
                   
               
               
                 Hydrophilic Domain— 
                 polyvinylpyrrolidone  
                 11.49 wt % 
               
               
                 11.5 wt % 
                 (Kollidone 90K) 
                   
               
               
                 Active Agent—15 wt % 
                 donepezil base 
                  15.0 wt % 
               
               
                   
               
            
           
         
       
     
     While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and sub-combinations thereof. It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope.