Abstract

A sustained-release coated pharmaceutical tablet comprising a drug-containing tablet and a coating or membrane surrounding the same, wherein the coating or membrane is water-insoluble and insoluble in gastrointestinal fluids and consists essentially of a terpolymer of polyvinylchloride, polyvinylacetate, and polyvinylalcohol and a water-soluble pore-creating substance, the said pore-creating substance being randomly distributed in said terpolymer coating, said pore-creating substance being present in amount of one part to 35 parts for each one to ten parts of terpolymer, said coated tablet exhibiting a substantially constant dissolution rate during a major portion of its dissolution time when exposed to gastrointestinal fluids, especially wherein the terpolymer contains 80 to 95% weight per weight of polyvinylchloride, 0.5 to 19% weight per weight of polyvinylacetate, and 0.5 to 10% weight of polyvinylalcohol, and a method for the preparation thereof, are disclosed.

Other References

• Bonnet, C.A. 83, #180527x, (1975)
• Rice, C.A. 71, #103242a, (1969)
• Drinberg, C.A. 77, #128188z, (1972)
• Ando, C.A. 87, #7649y, (1977)
• Kimoto, C.A. 89, #25668z, (1978)
• Kawasaki, C.A. 89, #25678c, (1978)
• Taguchi, C.A. 80, #146770z, (1974)
• Comstock, C.A. 71, #51335m, (1969)
• Kallstrand and Ekman, Journal of Pharmaceutical Sciences 72, No. 7, (Jul. 1983), pp. 772-775
• "Research Disclosure", vol. 135, (Jul. 1975), item 13577, entitled Process for Making Microporous Membranes