Study the Effect of Neem Gum and Hydroxy Propyl Methyl Cellulose on Floating and Bioadhesive Gastroretentive Matrix Tablet Using Central Composite Design

The main objective of this study was to develop a gastroretentive dosage form of Atorvastatin calcium with bioadhesion and floating properties. Thirteen matrix tablets were formulated using different ratios of hydroxypropylmethylcellulose (HPMC K4M) and Neem gum as release controlling agent. Also Sodium bicarbonate (NaHCO3) was used as gas generating agent. The study discussed the application of Central composite design (CCD) and response surface methodology (RSM) for the optimization of process parameters i.e. concentration of Neem gum and HPMC K4M, affecting the drug release, floating and mucoadhesive properties. The range of values of the independent variable used were, flag time of as minimum as possible, mucoadhesive strength of > 20 g, drug release at 2 h of 20% to 25% and drug release at 8 h of 60% to 70%. The Predicted values were found to be in good agreement with experimental values for all three response variable. Drug release profiles of all formulations followed Higuchi model with non- fickian diffusion mechanism. The magnitude of the coefficient of correlation of the fitted quadratic equations revealed that both Neem gum and HPMC K4M has negative effect on the floating lag time and drug release profile, and positive effect on mucoadhesive strength.