Effect of Different Polymer Concentration on Drug Release Rate and Physicochemical Properties of Mucoadhesive Gastroretentive Tablets

Mucoadhesive tablets have emerged as potential candidates for gastroretentive drug delivery providing controlled release along with prolonged gastric residence time. Gastroretentive mucoadhesive tablets could result in increased bioavailability due to prolonged gastric residence time. A hydrophilic matrix system was developed as mucoadhesion is achievable on appropriate wetting and swelling of the polymers used. The polymers were so chosen so as to provide a balance between swelling, mucoadhesion and drug release. The polymers chosen were hydroxypropyl methylcellulose K4M, chitosan, and Carbopol 934. The concentrations of these polymers used has a great impact on the physicochemical properties of the resulting formulation. The tablets were formulated using wet granulation method and tranexamic acid was used as the model drug. The prepared tablets were characterized for size, shape, appearance, hardness, friability, weight variation, swelling, mucoadhesion and in vitro drug release. Several batches of tablets were prepared by varying the ratio of hydroxypropyl methylcellulose K4M and Chitosan. The batches having a greater ratio of chitosan showed higher rate of swelling, greater erosion, less mucoadhesion and faster release rate of the drug whereas the batches having greater ratio of hydroxypropyl methylcellulose K4M showed lesser rate of swelling, less erosion, better mucoadhesion and a smaller drug release rate. The level of carbopol was kept constant in all the batches.