PHARMACEUTICAL COMPOSITION WITH PROLONGED RELEASE CONTAINING NIFEDIPIN AND PROCESS OF ITS PREPARATION

摘要

A sustained release composition containing Nifedipine (I) is new. (I) is co-precipitated in-situ with polyvinylpyrrolidone and the precipitate is embedded in a mixture of a water soluble excipient (e.g. lactose) and a hydrophilic matrix forming polymer (e.g. hydroxypropylmethylcellulose). The composition provides a prolonged and nearly constant rate of drug absorption for /- 24 hours. The ratio of Nifedipine to polyvinylpyrrolidone is preferably 1:1 to 1:3. The ratio of Nifedipine to lactose is preferably 1:3 to 1:10 and the ratio of Nifedipine to hydroxypropylmethylcellulose is preferably 1:0.5 to 1:3. The average molecular weight of the polyvinylpyrrolidone is 40000 and various grades of hydroxypropylcellulose may be used ranging from 4000-100000 cps. The lactose may be replaced by other inert excipients e.g. mannitol, sorbitol, sucrose or glucose. The hydroxypropylcellulose may be replaced by hydroxyethylcellulose or methylcellulose.