Effect of water-soluble carriers on morphine sulfate release from a silicone polymer

The influence of gelatin, sodium lauryl sulfate, lactose, and sodium alginate on morphine sulfate diffusion from cylindrical silicone polymer pellets was examined in isotonic pH 7.4 phosphate buffer. These water-soluble carriers caused the pellets to swell in aqueous media. Sodium alginate exerted the greatest influence on drug release. The morphine sulfate diffusion rate from the cylindrical pellets increased as the matrix alginate content increased up to 20%. Water-soluble carrier incorporation into silicone polymeric matrixes permits controlled release of water-soluble drugs that otherwise would be released extremely slowly from the polymer. Drug diffusion from the silicone matrix containing sodium alginate followed second-order kinetics. The release mechanism probably involves the creation of pores or pathways through the matrix secondary to the swelling.