Formulation and Evaluation of Polymer Effect on In-Vitro Kinetics of Sustained Release Matrix Tablets of Carvedilol Using Model Dependent Methods

The present study was designed to evaluate the polymeric effect of METHOCEL K15MCR on the sustained release drug product of Carvedilol. Carvedilol matrix tablets were formulated by direct compression method using METHOCEL K15MCR polymer in various percentages. Physical parameters were tested and the dissolution procedure was performed by using USP (II) paddle method for eight hours to examine the release kinetics. In the study, METHOCEL K15MCR polymer was found to cause the strong retardation of the drug release. The release mechanism was explored and explained with zero order, first order, Higuchi and Korsmeyer-Peppas equations. In the context, it can be suggested with a satisfactory result that this sustained release Carvedilol tablets can be marketed to treat patient ensuring proper healthcare. DOI: http://dx.doi.org/10.3329/ijpls.v2i2.15452 International Journal of Pharmaceutical and Life Sciences Vol.2(2) 2013: 70-79

Rheology of carboxymethyl cellulose solutions treated with cellulases

The effect of cellulase treatments on the rheology of carboxymethyl cellulose (CMC) solutions was studied using a rotational viscometer. The rheological behaviors of CMC solutions of different molecular mass and degrees of substitution where studied as a function of time after various treatments. These solutions were subjected to active and heat-denatured cellulase, a cationic polyelectrolyte (C-PAM), as well as different shear rates. A complex protein-polymer interaction was observed, leading to a potential error source in the measurement of enzymatic activity by changes in the intrinsic viscosity. The interaction was termed a polymeric effect and defined as a reduction in viscosity of the substrate solution without significant formation of reducing sugars from enzymatic hydrolysis. The cause of the reduction in viscosity appears to be related to the interaction between the enzymes as amphipathic particles and the soluble CMC. Thus, the polymeric effect may cause a considerable experimental error in the measurement of enzymatic activity by viscometric methods.