Abstract: The invention relates to a novel diffusion-osmotic controlled drug-release pharmaceutical composition containing a one-layer tablet core including a polymeric film-coat, a therapeutically active agent and a hydrophilic polymer; if desired, a two-layer tablet core including active agent and hydrophilic polymer in the first layer thereof and a hydrophilic polymer in the second layer thereof; at least one bore on the part of film-coat in contact with the core or core layer containing the active agent; and, if desired, containing one or more bore(s) in the part thereof in contact with the second layer containing the hydrophilic polymer, which comprises an ammonium methacrylate copolymer as coating material and hydroxypropyl-methylcellulose as hydrophilic polymer. The composition according to the invention is useful for preparing controlled drug-release tablets containing as active agents e.g. .beta.-adrenergic inhibitors (e.g. propranolol) calcium-antagonists (e.g.

Abstract: The present invention relates to a process for the preparation of regulated release solid pharmaceutical compositions comprising 4-(2'-nitro-phenyl)-2,6-dimethyl-3,5-dimethoxycarbonyl-1,4-dihydro-pyridin e (referred to further on as "nifedipine") as active ingredient which comprises admixing a solution or solutions of 1 part by weight of nifedipine, 0.1-1.5 parts by weight of one or more hydrophilizing agent(s) and 0.05-1.5 parts by weight of one or more retarding agent(s) formed with one or more identical or different solvent(s) completely or partly and applying the solution(s) thus obtained simultaneously or in succession onto an inert carrier, drying and sieving the product thus obtained and subsequently admixing the same with suitable conventional auxiliary agents and compressing the mixture thus obtained to tablets in a known manner and coating the tablets or filling the mixture into capsules.