United States Patent:  6,024,976

Assignee:  Noven Pharmaceuticals, Inc. (Miami, FL)

Filed:  August 11, 1997

A blend of at least two polymers, or at least one polymer and a soluble polyvinylpyrrolidone, in combination with a drug provides a pressure-sensitive adhesive composition for a transdermal drug delivery system in which the drug is delivered from the pressure-sensitive adhesive composition and through dermis when the pressure-sensitive adhesive composition is in contact with human skin. According to the invention, soluble polyvinylpyrrolidone can be used to prevent crystallization of the drug, without affecting the rate of drug delivery from the pressure-sensitive adhesive composition.

SUMMARY OF THE INVENTION

The foregoing and other objects are achieved by this invention which provides a transdermal drug delivery system wherein a blend of at least two polymers, or at least one polymer and a soluble polyvinylpyrrolidone permits increased loading of a drug and adjusts the solubility of a drug in the blend and thereby modulates the delivery of the drug from the system and through the dermis.

In accordance with one aspect of the invention, an improved pressure-sensitive adhesive composition of the type which is suitable as a matrix for controlled release of a drug therefrom comprises a blend of a rubber-based pressure-sensitive adhesive and a soluble polyvinylpyrrolidone (PVP).

The term "polyvinylpyrrolidone," or "PVP" refers to a polymer, either a homopolymer or copolymer, containing N-vinylpyrrolidone as the monomeric unit. Typical PVP polymers are homopolymeric PVPs and the copolymer vinyl acetate vinylpyrrolidone. The homopolymeric PVPs are known to the pharmaceutical industry under a variety of designations including Povidone, Polyvidone, Polyvidonum, Polyvidonum solubile, and Poly(1-vinyl-2-pyrrolidone). The copolymer vinyl acetate vinylpyrrolidone is known to the pharmaceutical industry as Copolyvidon, Copolyvidone, and Copolyvidonum.

The term "soluble" when used with reference to PVP means that the polymer is soluble in water and generally is not substantially cross-linked, and has a molecular weight of less than about 2,000,000. See, generally, Buhler, KOLLIDON.RTM.: POLYVINYLPRYRROLIDONE FOR THE PHARMACEUTICAL INDUSTRY, BASF Aktiengesellschaft (1992).

It has been surprisingly found that use of a soluble PVP results in the ability to form a film that does not contain particles of insoluble PVP and in the ability to employ higher concentrations of drug without resulting in increased crystallization of the drug.

In accordance with another embodiment of the invention, an improved pressure-sensitive adhesive composition of the type which is suitable as a matrix for controlled release of a drug therefrom comprises a blend of a rubber-based pressure-sensitive adhesive having a first solubility parameter, a polyacrylate polymer having a second solubility parameter, and a soluble PVP, the first and second solubility parameters preferably being different from one another by an increment of at least 2 (J/cm³)^1/2. The blend, therefore, has a characteristic net solubility parameter.

In accordance with further embodiment of the invention, an improved pressure-sensitive adhesive composition of the type which is suitable as a matrix for controlled release of a drug therefrom comprises a blend of a rubber-based pressure-sensitive adhesive having a first solubility parameter, and a polyacrylate polymer having a second solubility parameter, the first and second solubility parameters preferably being different from one another by an increment of at least 2 (J/cm³)^1/2. The blend, therefore, has a characteristic net solubility parameter.

Particularly preferred embodiments include binary blends comprising a rubber-based pressure-sensitive adhesive and a soluble PVP, wherein the rubber-based pressure-sensitive adhesive is a polysiloxane. Polysiloxane is preferably present in the pressure-sensitive adhesive composition in an amount ranging from about 9% to about 97% by weight of the total pressure-sensitive adhesive composition.

Other particularly preferred embodiments include ternary blends comprising a rubber-based pressure-sensitive adhesive, a polyacrylate polymer, and a soluble PVP, wherein the rubber-based pressure-sensitive adhesive is a polysiloxane. Polysiloxane is preferably present in the pressure-sensitive adhesive composition in an amount ranging from about 9% to about 97% by weight of the total pressure-sensitive adhesive composition, while the polyacrylate polymer is preferably present in an amount ranging from about 5% to about 85%. Preferably, the ratio of the polyacrylate polymer to the rubber-based pressure-sensitive adhesive is from about 2:98 to about 96:4, and more preferably from about 2:98 to about 86:14 by weight.

Other particularly preferred embodiments include blends comprising a rubber-based pressure-sensitive adhesive and a polyacrylate polymer, wherein the rubber-based pressure-sensitive adhesive is a polysiloxane. Polysiloxane is preferably present in the pressure-sensitive adhesive composition in an amount ranging from about 9% to about 97% by weight of the total pressure-sensitive adhesive composition, while the polyacrylate polymer is preferably present in an amount ranging from about 5% to about 85%. Preferably, the ratio of the polyacrylate polymer to the rubber-based pressure-sensitive adhesive is from about 2:98 to about 96:4, and more preferably from about 2:98 to about 86:14 by weight.

In both binary and ternary blends, soluble PVP is preferably present in the pressure-sensitive adhesive composition in an amount ranging from about 1% to about 20% by weight of the total pressure-sensitive adhesive composition.

The pressure-sensitive adhesive compositions may further include enhancers, fillers, co-solvents, and excipients as are known in the art for use in such compositions.

In a dermal adhesive composition embodiment of the invention, a multiple polymer adhesive system comprises a blend of 14-94% by weight of a rubber-based pressure-sensitive adhesive, 5-85% by weight of a polyacrylate polymer, and 2-10% by weight of a soluble PVP, and the multiple polymer adhesive system comprises about 50-99% by weight of the dermal adhesive composition. This multiple polymer adhesive system is combined with a drug in the amount of 0.1-50% by weight of the total dermal adhesive composition. Optional additives, such as co-solvent for the drug (up to 30% by weight) and enhancers (up to 20% by weight) may be included in the dermal adhesive composition.

In transdermal drug delivery system embodiments, incorporating a drug in the improved pressure-sensitive adhesive composition, the characteristic net solubility parameter can be preselected to adjust the saturation concentration of the drug in the composition and thereby control the release of the drug. The saturation concentration of the drug may be adjusted either upward or downward depending upon whether the rate of release is to be enhanced or retarded.

In particularly preferred embodiments, the drug is a steroid, such as an estrogen or a progestational agent, or combination thereof. In other preferred embodiments, the drug may be a .beta.₂ -adrenergic agonist, such as albuterol, or a cardioactive agent, such as nitroglycerin. In still other embodiments, the drug is a cholinergic agent, such as pilocarpine, or an antipsychotic such as haloperidol or a tranquilizer/sedative such as alprazolam.

The transdermal drug delivery system may comprise a monolithic adhesive matrix device in some embodiments. The transdermal drug delivery system may further include a backing material and a release liner as is known in the art.

The saturation concentration of a drug in a transdermal drug delivery system of the type having a drug-containing pressure-sensitive adhesive diffusion matrix is adjusted in accordance with an aspect of the present invention by blending at least two polymers having differing solubility parameters as defined above to form a pressure-sensitive adhesive diffusion matrix having a net solubility parameter which modifies the delivery rate of the drug from the pressure-sensitive adhesive diffusion matrix and through the dermis.

Claim 1 of 66 Claims

1. A transdermal drug delivery system comprising a pressure-sensitive adhesive composition, wherein said composition comprises a blend of (1) a synthetic elastomeric polymer; (2) a soluble PVP and (3) at least one drug.

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