Abstract

STUDIES ON THE EVALUATION OF DIFFERENT VISCOSITY GRADES OF GUAR GUM AS HYDROPHILIC MATRIX FOR ORAL CONTROLLED DELIVERY OF DILTIAZEM HCL

Rama Rao Tadikonda* and Satyanarayana Sreemantula

Abstract

In the present study different viscosity grades of guar gum were evaluated in the form of hydrophilic matrix for oral controlled drug delivery. Freely soluble diltiazem HCl was chosen as model drug. Hydrophilic matrix tablets of diltiazem HCl using different proportions of various viscosity grades of guar gum were prepared by wet granulation method and subjected to in vitro drug release studies. Diltiazem HCl matrix tablets containing either 30% low-viscosity guar gum (DLV-30), 40% medium-viscosity guar gum (DMV-40) or 50% high-viscosity guar gum (DHV-50) were found to provide matching release profiles with that of commercial SR diltiazem HCl tablets (DCSR). High correlation coefficients were obtained for first order kinetics when compared to those of zero order kinetics indicating that diltiazem HCl release from all the formulations followed first order kinetics. The diffusional exponent values (n=0.46 to 0.50) indicated that the release of diltiazem HCl from guar gum matrix tablets and commercial SR tablets followed fickian diffusion. The similarity factor (ƒ2) values of the diltiazem HCl formulations DLV-30, DMV- 40, DHV-50 and D-CSR were found to be 50.34, 56.65, 50.95 and 55.01 respectively i.e., greater than 50 indicating that the drug release behavior of these formulations was similar to the theoretical release profile.

Keywords: Controlled release, Diltiazem HCl, Low-viscosity guar gum, Medium-viscosity guar gum, High-viscosity guar gum, Matrix tablets.