Understanding the Impact of Polymer Ratio and its Concentration on Omeprazole Release from Matrix Tablets: Response Optimization Study

Abstract

In present study, matrix tablets of Omeprazole (OPZ) were formulated by wet granulation technique using a combination of hydroxyl propyl methyl cellulose (HPMC K15M) and ethyl cellulose (EC) in varying ratios and the effect of polymer ratio as well as their concentration on drug release profile was investigated. Response surface methodology (RSM) was conducted to optimize matrix tablets. Compressed tablets were evaluated for hardness, friability, weight variation, drug content and in vitro dissolution studies. The dissolution study was performed in pH1.2 for the first 2 h and in phosphate buffer (pH 7.4) for another 5 h. The optimized formulation was compared with other formulations using similarity (ƒ2) and dissimilarity factor (ƒ1) test. The results of RSM indicated that both X1 (the blending ratio of HPMC K15M K15M and Carbopol 934P 934P) and X2 (polymer blend concentration)have significant effect on in-vitro drug release profile. Hardness, friability, weight variation and drug content were found to be in desired range. Among different formulations, matrix tablets prepared by HPMC K15M and Carbopol 934P 934P (7:3) with 15% polymer blend concentration displayed 98.85% OPZ release in 7 hr. and release kinetic was higuchi (r 2= 0.9884). Similarity (f2) and dissimilarity (f1) factors demonstrated that the in vitro profiles were not similar. Finally, it was concluded that release rate of OPZ decreased proportionally with increasing polymer ratio (HPMC K15M: Carbopol 934P 934P) and decreasing polymer blend concentration.