Development of Bioadhesive Buccal Tablets of Nicorandil Using a Factorial Approach

In the present investigation, bioadhesive buccal tablets were prepared using the sustained-release polymer hydroxypropyl methylcellulose (HPMC) K100M, bioadhesive polymer neem gum, and an impervious backing layer of ethyl cellulose. Nicorandil is sensitive to the first-pass effect; therefore, a buccal-adhesive dosage form can avoid this effect.

We used the direct compression technique to prepare the tablet formulation. A 3² full factorial design was composed in which the amounts of HPMC K100M (X1) and neem gum (X2) were chosen as the independent variables and the dependent variables were the percentage drug release at 6 h (Y1) and mucoadhesive strength in grams (Y2). Various in vitro parameters, i.e. thickness, friability, hardness, weight variation, surface pH, moisture absorption ratio, dissolution studies, and drug release kinetics, and ex vivo parameters like mucoadhesive strength and mucoadhesion time were determined for the prepared tablets. We subjected the optimized batch to a comparison with the marketed formulation and stability studies were performed.

The formulation containing a 50:50 ratio of neem gum and HPMC K100M (F5) was considered optimum. The zero-order release kinetics model best fitted the optimized batch release profile, suggesting the system would release the drug at a constant rate.

The release by the optimized formulation of the drug at a sustained rate along with its bioadhesive nature showed that the buccal route can be an option for the administration of nicorandil.