The influence of the composition and charges of the acrylic resins, the hydrophilic polymer, and the other excipients on the release rate of drug from the matrices.

Abstract

The effect of the hydrophilic polymers such as sodium carboxymethyl cellulose, (NaCMC) and the hydrophobic polymers such as Eudragit RL100 and Eudragit RS 100 on the dissolution and the release rate of drug when prepared as controlled release matrices were studied. Tablets were prepared by a direct compression technique. The dissolution tests were performed by both the basket and the paddle methods. In the present study the acrylic resins Eudragit RS 100 and Eudragit RL 100 are separately mixed with the anionic and hydrophilic polymer NaCMC and the other excipients in an attempt to prepare controlled release matrices and to investigate the effect of the charge and composition of these polymers on the drug release. Also the research will study the effect of the pH of the dissolution medium, and the storage of the matrices at different temperatures, on the release rate of the drug. It was found that percent, charge of the polymers, pH of the dissolution medium and storage of matrices at different temperatures affect the release rate of the drug. The experiments were performed in vitro and the data obtained were plotted according to four kinetic models to study the release kinetic. These models were zero order release, first order release, Higuchi equation, and Korsmeyer equation. Zero order release was observed in the formulation with a high percent of the hydrophilic polymers, while high percent of hydrophobic polymers didn't show zero order release and the drug was liberated in a less time from the matrices.