Studies on buccoadhesive tablets of terbutaline sulphate

An attempt has been made to develop buccoadhesive bilayered tablets comprising of drug containing bioadhesive layer and drug free backing layer to release the drug for extended period of time with reduction in dosing frequency. Tablets of terbutaline sulphate were prepared by direct compression method using bioadhesive polymers like Carbopol 934P, Methocel K4M, Methocel K15M and sodium carboxy methyl cellulose either alone or in combinations with backing layer of ethyl cellulose. The physical characteristics, swelling index, surface pH, in vitro bioadhesion strength, and in vitro release of formulated tablets were shown to be dependent on characteristics and composition of bioadhesive materials used. The modified in vitro assembly was used to measure and compare the bioadhesive strength of tablets with fresh porcine buccal mucosa as a model tissue. The maximum bioadhesive strength was observed in tablets formulated with Carbopol 934P alone and strength decreases with decrease in its content. The tablets were evaluated for in vitro release in pH 6.8 phosphate buffer for 10 h using a standardized dissolution apparatus. In order to determine the mode of release, the data was subjected to Korsmeyer and Peppas diffusion model. All the formulations followed non-Fickian release mechanism. Carbopol 934P and Methocel K4M in the ratio of 1:1 could be used to design effective and stable buccoadhesive tablets of terbutaline sulphate.