Formulation and Evaluation of Sustained Release Dosage Form of Nifedipine Hydrochloride Using Hydrophilic Polymers

Sustained release oral delivery systems are designed to achieve therapeutically effective concentrations of drug in the systemic circulation over an extended period of time. The purpose of the present investigation was to design and evaluate sustained release matrix tablets of nifedipine, a poorly water soluble drug, employing hydroxypropyl methyl cellulose (HPMC) and ethyl cellulose (EC) as hydrophilic polymers. Direct compression method was used to prepare matrix tablets. Drug content uniformity, friability test were performed and the in vitro drug release profiles were compared with the innovator product (Procardia) benefiting similarity factor (f2) and difference factor (f1). In all formulations content uniformity was in the acceptable range. Most of the prepared formulationspassed friability test. Formulation containing HPMC and EC in the ratio of 88.5:5 showed acceptable dissolution properties compared to reference formulation. Fitting the release data to the kinetic models indicated that the best fitted kinetic model for the prepared matrix tablets and Procardia were zero order and Weibull model, respectively. This study indicates that the hydrophilic matrix tablets of nifedipine prepared using HPMC and EC can successfully be employed as sustained release matrix tablet in order to improve patient compliance.