Pharmaceutical delivery system

Abstract

A composition for use in an aqueous environment which .[.comprise.]. .Iadd.comprises .Iaddend.a formulation containing a water-soluble pharmaceutically beneficial agent, a water-insoluble, water-permeable film coating surrounding the formulation, and particulate, water-soluble, pore-forming material dispersed within the film coating. The questions raised in reexamination request No. 90/001,344, filed Oct. 5, 1987, have been considered and the results thereof are reflected in this reissue patent which constitutes the reexamination certificate required by 35 U.S.C. 307 as provided in 37 CFR 1.570(e).

What we claim is: .[.1. A tablet comprising a core containing the admixture of a water-soluble medicine and a water-soluble osmotic enhancing agent in an amount by weight about equal to or greater than the weight of the medicine, said core having a water-insoluble, water-permeable coating surrounding said core, said coating-containing particulate, water-soluble, pore-forming material dispersed therein..]. .[.2. The tablet of claim 1 in which the osmotic enhancing agent is a pharmaceutically acceptable water-soluble sugar or salt..]. .[.3. The tablet of claim 2 in which the pore forming material dispersed in the coating is a pharmaceutically acceptable water-soluble sugar or salt..]. .[.4. The tablet of claim 1 in which the osmotic enhancing agent and the pore-forming material are both lactose..]. .[.5. A composition comprising a core containing the admixture of a water-soluble medicine and a water-soluble osmotic enhancing agent in an amount by weight about equal to or greater than the weight of the medicine, said core having a water-insoluble, water-permeable coating surrounding said core, said coating containing particulate, water-soluble pore-forming material dispersed therein and an agent to increase the water 
     
        permeability of the coating dispersed therein..]. .[.6.  The composition of claim 5 wherein the water permeability increasing agent is polyethylene 
     
     
        glycol..]. .Iadd.7.  A controlled release composition for oral administration comprising bupropion hydrochloride in solid sustained release pharmaceutical carrier, said composition releasing about 10% to 45% of bupropion hydrochloride within two hours, releasing about 25% to 70% of bupropion hydrochloride within four hours, and releasing about 40% to 90% of bupropion hydrochloride within six hours, as measured in simulated gastric buffer with a pH of 1.5 at 37° C. .Iaddend.