Evaluation of films used in development of a novel controlled-release system for gastric retention

Abstract

A novel gastric retention system was developed consisting of a tablet coated with a porous membrane. The membrane consisted of aqueous dispersions of methyl methacrylate copolymers, plasticizers, anti tacking and anti foaming agents. This article presents research work performed in order to characterize these membranes. The films were cast on glass plates coated with teflon. The films were dried at 30°C in a vacuum oven. The three main properties studied on these films were as follows: (1) Transport of drugs across the membrane; (2) mechanical properties; (3) thermo-mechanical properties. These properties were studied to produce a film having the desired characteristics for drug release and mechanical strength. It was observed that the permeability of the drug decreased slightly with increase in the Eudragit® NE 30D concentration. This result correlated well with dissolution rate constants of tablets at 15% coating level. The thermo-mechanical studies helped to understand the results from permeability studies. Based on mechanical properties, a 70:30 ratio of Eudragit® RL 30D and NE 30D was found to be optimum. The study has shown that the evaluation of films will be helpful in providing guidelines in selecting the membrane for the gastric retention system.