Formulation and Evaluation of Gastroretentive Matrix Tablet of Nifedipine

The present investigation concerns the formulation and evaluation of floating matrix tablets of Nifedipine which after oral administration, are designed to prolong the gastric residence time, increase drug bioavailability and sustain the drug release. Nifedipine is a calcium channel blocker, used in treatment of moderate to severe angina and hypertension. It offers several advantages such as rapid absorption, reducing peak plasma fluctuation and ease of administration.

In present study, controlled release tablet was prepared using wet granulation of Nifedipine and hydrophilic polymers (HPMC K15M and K100M). All formulations had floating lag times below 3 minutes and constantly floated on dissolution medium for 24 hrs. The optimized formulations were subjected to various kinetic release investigations and it was found that the mechanism of drug release was predominantly diffusion in combination with polymeric relaxation. Results of the drug interaction studies suggest that all the studied excipients are compatible with Nifedipine. DSC thermo grams showed that there was no interaction was found. Precompression parameters Nifedipine showed good compressibility and flow property. The hardness and friability were within specified range. The best formulation (F3) remained buoyant and showed a sustained drug release for 24hrs. F3 showed no significant change in physical appearance, drug content or floating lag time after storage at 45°C/75% RH for three months.