Design, statistical optimization of Nizatidine floating tablets using natural polymer

摘要

Background:The present research was aimed in developing gastroretentive tablets of Nizatidine, in order to increase the bioavailability of the drug. Nizatidine belongs to BCS class 3 and thus formulating into gastroretentive tablets helps to achieve a better therapeutic effect. There were no reports available on the use of Mimosa gum in the design of gastroretentive drug delivery systems. Response surface methodology was employed to optimize the formulation with suitable experimental design. The goal of the response surface methodology was to obtain a regression model and to find a suitable approximation for the true functional relationship between the response and the set of independent variables. Hence, the statistical approach like full factorial design was utilized to obtain optimized formulation with a smaller number of experiments.ResultsDSC study justified no interaction of the drug with excipients. The floating lag time was observed to be less than 20 s, total floating time was in the range of 8–24 h, hardness ranges from 4 to 5 kg/cm2, and friability was less than 1%. Dissolution data indicated that the higher viscosity of Mimosa (2%) delayed the drug release for extended period of time up to 23 h when compared to lower viscosity Mimosa (1%), which controlled the release of the drug up to 12 h only. The ‘n’ values of all the prepared formulations were found to be 0.59 to 0.81 indicating that the release mechanism followed anomalous (non-Fickian) diffusion. The optimal values of independent test variables were obtained from the overlay plots. The optimized formulation of Mimosa gum (2%) (M2%_opt) contained 170 mg of polymer and 25.5 mg (15%) of sodium bicarbonate. Similarly, the optimized formulation of Mimosa (1%) (M1%_opt) contained 255 mg of polymer and 34 mg (10%) of sodium bicarbonate.ConclusionThe results clearly indicated that the optimized formulations followed zero-order release kinetics with diffusion mechanism as per the predicted theoretical release rate confirming the suitability of the predicted theoretical release profile.