Development and characterization of buccoadhesive nifedipine tablets

The buccoadhesive controlled-release tablets for delivery of nifedipine were prepared by direct compression of carboxymethyl cellulose (CMC) with carbomer (CP), which showed superior bioadhesion properties compared to polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), hydroxypropylmethyl cellulose (HPMC), and acacia in a modified tensiometry method in vitro. The tablets containing 30 mg of nifedipine and various amounts of CMC and CP showed a zero-order drug release kinetic. The adhesion force was significantly affected by the mixing ratio of CP:CMC in the tablets. The weakest and highest adhesion force was observed at the mixing ratios of 1:0 and 8:2 of CP:CMC, respectively. The tablets containing 15% CMC and 35% CP adhered for over 8 h to the upper gums of six healthy human volunteers. These tablets released about 56% of the loaded drug after 8 It in vivo with a rate of 2.17 h(-1) and were perfectly tolerated, while they released about 100% of their content after the same time with a rate of 3.49 h(-1) in vitro. A good correlation (r(2) = 0.989) was observed between drug-released in vitro and in vivo. (C) 2002 Elsevier Science B.V. All rights reserved.