Abstract

The present investigation concerns the formulation and evaluation of floating tablets of zolpidem tartrate which after oral administration are designed to prolong the gastric residence time and increase drug bioavailability. A floating drug delivery system (FDDS) was developed using gas-forming agents like sodium bicarbonate and citric acid and polymers Hydroxyl propyl methyl cellulose (HPMCK4M) and xanthan gum. The prepared tablets were evaluated in terms of their precompression and post compression parameters, buoyancy lag time, total floating time and in-vitro drug release. The formulations were optimized for the grades of HPMCk4M and xanthan gum and its concentrations and combinations. The results of the in-vitro drug release studies showed that the optimized formulation (F12) could sustain drug release i.e.95.6% for12hrs and buoyancy lag time and total floating time were found to be 59sec and >24 hrs respectively. The mechanism of drug release for optimized formulation F12 was found to be Non-Fickian diffusion transport with Zero order of release. Optimized formulation (F12) showed no significant change in physical appearance, drug content, total buoyancy time and in-vitro dissolution study after storage at 400 C/75% RH for three months. Zolpidem tartrate floating tablets prepared by employing xanthan gum at concentration 57.5%w/w with 10% w/w sodium bicarbonate and 5% citric acid (F12) was the best formulation with desired in-vitro floating time and drug dissolution.

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