Mucoadhesive sustained delivery of diclofenac sodium using carbopol 675 and PVP admixtures as mucoadhesive motif

The mucoadhesiveness, swelling characteristics and release profile of diclofenac sodium from mucoadhesive tablets prepared with Carbopol 675 and polyvinyl pyrrolidone (PVP) and their physical mixtures were studied to evaluate their applicability in sustained drug delivery. The ex-vivo mucoadhesive strengths of the tablet compacts were determined by tensiometry using Lecomte du Nuoy tensiometer and everted pig jejunum. Release studies were carried out in three different pH media (1.2, 7.0 and 7.5). The results of mucoadhesive test revealed that tablets formulated from 1:1 physical mixture of Carbopol 675 and PVP had the highest mucoadhesive strength, which showed they bound tightly to the mucus pig jejunum. Their low swelling and release behaviours also indicated that the tablet compacts are very good candidates for sustained release formulation since release of diclofenac sodium was sustained by the compacts.