Formulation and evaluation of sustained release matrix tablets of nifedipine

Abstract

Nifedipine is a calcium channel blocker, which has short half-life, makes the development of sustained release (SR)
dosage form. The present work was to formulate a sustained release matrix dosage form of Nifedipine by using
hydrophilic polymer (HPMC) and hydrophobic polymer (Ethyl cellulose) to achieve better bioavailability and also to
reduce dosing frequency and side-effects. Nifedipine matrix tablets were prepared by direct compression method.
Formulated tablets were also characterized by parameters like thickness, weight variation test, drug content uniformity,
hardness, friability and the in-vitro release rate profile was compared with the marketed product’s release profile. FT-IR
spectra revealed that there was no interaction between drug and polymers. Tablets were subjected to In-Vitro drug release
in 0.1 N HCl (pH 1.2) for first 2 hours followed by phosphate buffer (pH 6.8) for remaining 10 hours. From among all
the developed formulations, NF2 formulation sustained the drug release for longer period of time as compared to
other formulations. So, NF2 was selected as the best formulation. To know the drug release kinetics Zero order, First
order, Higuchi plot, Korsmeyer Peppa’s plot were constructed. For optimized formulations zero order plot showed
linearity with high regression coefficient values than the first order. According to ‘n’ values obtained from the Korsmeyer
peppa’s plot it may be concluded that the drug release is by fickian transport and drug release was controlled by diffusion
mechanism.