Multi-Layer Films Prepared by Spray Coating for Effervescent Floating Tablets

Abstract

This study proposed the preparation process for multi- layer films by spraying technique. The films were evaluated for mechanical properties, water contact angle and water vapor permeability for the development of effervescent floating tablets. The films consisted of 2 layers: a gas- forming layer and a gas- entrapped layer. NaHCO₃:HPMC (8:2) mixture was used as a gas- forming layer. Eudragit^® RL 30D plasticized with diethyl phthalate was used as the gas-entrapped layer. Multi-layer films were successfully prepared by spraying technique on Teflon cubes from 2 to 10 layers. The coating weight gain was 12% w/ w for the gas- forming layer and 10% w,w for the gas-entrapped layer. Increasing the number of layers enhanced puncture strength and elongation in the dry and wet states. However, the film’s flexibility was decreased at 10 layers due to the thickness of each layer. The increasing number of layers led to decreasing water contact angle and enhancing water vapor permeability coefficient suggesting the improvement of solvent penetration through the film.