Abstract In the current exploration a novel oral drug delivery system was developed utilizing the concepts of controlled release and mucoadhesiveness. Mucoadhesion is a topic of current interest in the design of drug delivery systems. Mucoadhesive microspheres exhibited a prolonged residence time at the site of application or absorption and facilitate an intimate contact with the underlying absorption surface and thus contribute to improved and/or better therapeutic performance of drugs. Nizatidine microspheres were equipped by emulsification-ionic gelation technique using mucoadhesive polymers such as Carbopol 934P, Hydroxypropyl methylcellulose (HPMC K15M) and Carboxy methyl cellulose with a rate controlling polymer sodium alginate. The arranged formulations were subjected to particle size and shape analysis, % drug entrapment efficiency, in vitro floatability, swelling rate, in vitro mucoadhesion test and in vitro drug release kinetics. The primed microspheres were discrete, spherical with a mean particle size in the range of 478±0.99μm to 640 ±2.67 μm. Entrapment efficiency was found to be in the range of 59.56±0.99 to 79.90± 1.78%. Formulations containing Carbopol 934P showed amplified in vitro mucoadhesion compared to formulations with Hydroxypropyl methylcellulose and CMC. In vitro drug release for all the formulations in 0.1N HCl was diffusion controlled progressively over a period of 12 h and followed First order kinetics. The in vitro drug release mechanism was nonfickian type controlled by swelling and relaxation of polymer. There was no noteworthy alteration in physico-chemical characteristics of the microspheres stored at diverse storage condition after 3 months of stability study. The fabricated system has the twofold advantages of being gastroretentive, to augment oral bioavailability and releasing drug in a controlled manner, to diminish the required frequency of administration thereby promoting patient compliance.
Keywords Gastroretentive drug delivery system, Nizatidine, HPMC, CMC, Non-fickian diffusion.