Drug excipient of silicone rubber
AssigneeSchering Corporation
InventorsGisela Schopflin, Peter Fuchs, Karl H. Kolb
Life of this patent
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Abstract
Nontoxic sustained release pharmaceutical compositions containing one or more nonionic, lipophilic drugs in a cured low temperature vulcanizable (LTV) silicone elastomer excipient are prepared substantially free of toxic vulcanizing agents or drug-reactive by-products in the elastomeric material by curing an admixture of the drug or drug containing core, LTV-methylvinylsiloxane units containing linear dimethylpolysiloxane and a dimethylpolysiloxane crosslinking composition containing silicon linked H atoms using a noble metal-based catalyst. The resultant compositions are characterized by good physical properties and a constant rate of drug release in the body over long periods of time.
Claims16
A nontoxic pharmaceutical composition adapted for implantation into a human or animal body to provide a constant, uniform drug release rate over a time interval of several months or years, said composition being substantially free of peroxide, acetic acid and metal salts of carboxylic acids and consisting essentially of a homogeneous mixture of:
- (a) 85-95 parts by weight of a LTV linear dimethylpolysiloxane resin containing 0.05-0.5 molar percent of methylvinylsiloxane units, having a molecular weight of 20,000-50,000 and containing an average of 1.58-2.02 monovalent hydrocarbon residues per silicone atom;
- (b) correspondingly 15-5 parts by weight of a crosslinking composition consisting essentially of a dimethylpolysiloxane crosslinking agent substantially free of methylvinylsiloxane units, having a molecular weight of 500-1000 and containing 1-3 Si--H bonds per molecule;
- (c) a catalytic amount of a noble-metal based crosslinking catalyst;
- and
- (d) a pharmaceutically active amount of a nonionic, lipophilic drug dissolved or uniformly suspended in said composition.
Dependencies are inferred from the claim text.