Evaluation of Ethylcellulose as A Matrix for Prolonged Release Formulations. I. Water Soluble Drugs: Acetaminophen and Theophylline

Abstract

In this study ethylcellulose was evaluated as a carrier for the preparation of prolonged release solid dispersions of relatively water soluble drugs, acetaminophen and theophylline. The solid dispersions containing various concentrations (7.5, 15.0 and 30.0 % by weight of drug) of ethylcellulose of different viscosity grades (21, 95, 209 and 350 cps) were prepared by the solvent method. The concentration of polymer in the formulation was the determining factor in controlling release rate of the drug, as the results indicate prolongation in release of the drug with increase in amount of ethylcellulose. The higher the viscosity grade of ethylcellulose, slower the release of drug from the solid dispersions. The release of drug from the tablets was more prolonged compared to the granular solid dispersions. In vitro release of acetaminophen and theophylline was more or less similar in both dissolution media. The viscosity grade of ethylcellulose showed slight influence on the release rate of drug from the tablet formulations, while it was quite noticeable in granular solid dispersions.