Volume 5

October-December 2013

Design and in vitro evaluation of mucoadhesive floating hollow microspheres of nizatidine with gastroretentive properties

Zaheer Abbas, Ravikiran Kanabargi

Abstract:
In the present investigation a novel oral drug delivery system was developed utilizing the concepts of controlled release and mucoadhesiveness, in order to obtain a unique drug delivery system which could remain in the stomach and control the drug release for an extended period of time. Nizatidine microspheres were prepared by emulsification-ionic gelation technique employing sodium alginate with mucoadhesive polymers such as Carbopol 934P and Hydroxypropyl methylcellulose. The prepared formulations were subjected to particle size and shape analysis, % drug entrapment efficiency, in vitro floatability, swelling rate, in vitro mucoadhesion and in vitro drug release studies. The prepared microspheres were discrete, spherical with a mean particle size in the range of 451 ± 1.21 µm to 645 ± 2.24 µm. Entrapment efficiency was found to be in the range of 77.4 ± 3.02% to 85.2 ± 0.56%. Formulations containing Carbopol 934P showed increased in vitro mucoadhesion compared to formulations with Hydroxypropyl methylcellulose. The % in vitro floating decreased and swelling rate increased with increase in the mucoadhesive polymer content at the end of 12 h. In vitro drug release for all the formulations in 0.1N HCl was diffusion controlled gradually 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 significant change in physico-chemical characteristics of the microspheres stored at different storage condition after 3 months of stability study. The developed system has the dual advantages of being gastroretentive, to increase oral bioavailability and releasing drug in a controlled manner, to reduce the required frequency of administration thereby promoting patient compliance.

Keywords: Nizatidine, Mucoadhesive Microspheres, Floating Microspheres, Hollow Microspheres, Gastro Retention, Emulsification-ionic Gelation.