ABSTRACT:
Nifedipine is a calcium antagonist, which is widely used as a coronary dilator in hypertension. It shows dose related side effects (10 mg – 100mg) with serum half-life of (2-5 hours). High incidence and severity of side effects have led to the search for new delivery system, which can overcome the side effects by controlling the rate of drug release. In this study Nifedipine controlled release matrix pellets were prepared using a novel blend of polymers called Gelucire. Gelucires were successfully used to prepare controlled release matrix pellets. Drug, Microcrystalline cellulose (Avicel PH101), Gelucire 50/13 and Gelucire 50/02 were mixed in suitable ratios so as to design a dosage form delivering 20 mg of drug to be administered once a day. Extrusion spheronization and Melt solidification method were used to prepare matrix pellets. Spheronization proved to be more efficient and successful in controlling the release of Nifedipine from matrix pellets in contrast to pellets prepared by Melt solidification method. The prepared pellets were characterized for micromeritic properties and polymer drug compatibility by FT-IR and DSC and surface morphology by SEM. The obtained values of micromeritic properties were within the limits indicating good flow properties. The surface morphology showed that prepared pellets were spherical and showed same surface texture. Dissolution studies showed that the release rate of drug from pellets decreased by increasing Gelucire and MCC content in the formulation. The in vitro release studies of pellets exhibited a t½ dependence indicating diffusion -controlled process. Stability studies were carried out for optimized formulation, for a period of 90 days at 40 ºC ? 75% RH, 30 ºC/65% RH and at 25 ºC/60% RH showed that there was no significant change in the drug content and hence the product is assumed to be stable.