Preparation and In Vitro Evaluation of a Microballoon Delivery System for Theophylline

Abstract

A multiple-unit oral floating system was prepared using the emulsification-solvent diffusion method to prolong the gastric emptying time of theophylline. For this purpose, theophylline, ethyl cellulose and dibutyl phthalate were dissolved in an ethanol/dichloromethane mixture, added to 0.1 M HCl containing NaCl (20%) or saturated theophylline and/or different concentrations of polysorbate 80 and polyvinyl alcohol. The mixture was stirred at different speeds for 3 h. The resulting microspheres were separated from the solution by filtration. Physical characteristics, including the shape and size distribution, floating capability, drug loading and drug release of the resulting theophylline microspheres were investigated.