Formulation and In vitro Evaluation of Gastroretentive Floating Bioadhesive Tablets of Nizatidine using Factorial Design

The aim of the present study was to formulate and evaluate floating bioadhesive tablets of Nizatidine which is a competitive, reversible H2-receptor antagonist. Floatingbioadhesive drug delivery system exhibiting a unique combination of floatation and bioadhesion to prolong gastric residence time was prepared. Polymers used were Hydroxy Propyl Methyl Cellulose (HPMC) K15M as matrix forming water swellable release retarding polymer and carbopol 934P as bioadhesive polymer. The gas generating agents used were sodium bicarbonate and citric acid. The prepared floating bioadhesive tablets of Nizatidine were optimized by 32 factorial design to study independent variable X1 (concentration of CP 934P) and X2 (concentration of HPMC K15M) and dependent variables as floating lag time, cumulative percentage drug release at 12h and swelling index. Tablets were evaluated for various parameters such as hardness, friability, drug content, swelling behavior, floating lag time, bioadhesive strength, drug release profile and stability. All the formulations passed the test for weight variation, hardness, content uniformity and showed acceptable results with respect to drug content (97.93 ± 0.57) and % friability. The tablet containing 25% HPMC K15M and 13.75 % Carbopol 934P was selected as optimized formulation which showed the floating lag time of 74.34±2.08 seconds, drug release of 97.03±0.55% at 12 h (R12h,%), S.I as 79.24±0.87 at 9 h and bioadhesive strength as 10.0023±21.47 g. Stability of the formulation was proved using stability study. The formulated tablets have a potential for controlled release of the drug through floatation and bioadhesion.