Design and Evaluation of Buccoadhesive Bilayer Tablets of Granisetron

Purpose of Study: In the present study, an attempt was made to design and evaluate buccoadhesive bilayer tablets of granisetron hydrochloride (an anti-emetic drug), in order to overcome bioavailability problems, to reduce dose dependent side effects and frequency of administration. Method: Bilayer buccal tablets containing the drug were prepared by direct compression method using combination of polymers (such as hydroxypropyl methylcellulose 15 cps, sodium carboxymethyl cellulose and Carbopol 934p.) and ethyl cellulose as backing layer. The designed tablets were evaluated for various physical and biological parameters, drug content uniformity, in-vitro drug release, short-term stability, drugexcipients interactions (FTIR). Results: The formulation HF1 with the drug matrix layer compositionhydroxypropyl methylcellulose 15 cps (47% w/w), Carbopol 934p (3%w/w), and mannitol (channeling agent, 45% w/w) was found to be promising. This optimized formulation exhibited an in vitro drug release of 94% in 8 h along with satisfactory bioadhesion strength (4.3 gm). Short-term stability studies on the promising formulation indicated that there are no significant changes in drug content and in vitro dissolution characteristics (p<0.05). IR spectroscopic studies indicated that there are no drug-excipient interactions. Conclusion: The present study proves that buccoadhesive bilayer tablets of granisetron hydrochloride with controlled drug release properties can be successfully prepared by direct compression method using HPMC 15 cps and Carbopol 934p as mucoadhesive polymers and ethyl cellulose as backing layer.