Abstract:

This work has focused on the effects of different hydroxypropylmethylcellulose (HPMC) types and HPMC:direct tabletting agent (DC-agent) ratio on Verapamil Hydrochloride (VRP HCl) release from monolayered and three-layered matrix tablets. Investigated polymers were Methocel K100LV, K15M, K100M and DC-agent was Ludipress® LCE. Eight formulations were prepared as monolayered matrix tablets while four formulations were prepared as three-layered matrix tablets by direct compression method. Drug release studies were carried out according to the method given for Delayed Release Articles in USP XXVII. HPMC types and ratios were found to be effective on drug release. Increasing amount and viscosity grade of HPMC resulted in a decrease in release of drug from the matrices. Tablets containing low viscosity grade HPMC at inner and outer layers presented release profiles close to or within the limits of pharmacopeia. Release data of three-layered matrix tablet (F12) and the reference product (Isoptin®KKH) which were in agreement with USP XXVII criteria, were evaluated by mathematical models (zero order, first order, Higuchi, Hixson-Crowell, Korsmeyer-Peppas), difference factor (f1) and similarity factor (f2). The kinetics of VRP HCl release from F12 showed best fit to Higuchi model and Isoptin®-KKH well fitted to zero order kinetic model. F12 and Isoptin®-KKH were both show Anomalous transport mechanism according to their n exponent values. Depending on the results of f1 (5.2) and f2 (71.4) values, F12 and Isoptin®-KKH were found to be similar with regard to release kinetics

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