Floating and Swelling Characteristics of Various Excipients Used in Controlled Release Technology

Abstract

During the past few years, great interest was developed in the subject of floating. In the present study, the floating and swelling characteristics of several excipients used controlled release technology were examined. The floating behavior was evaluated with resultant weight measurements, while a gravimetric method was employed for studying their swelling. The experiments were carried out in two different media, i.e. deionized water and simulated meal in order to monitor possible differences. The results indicated that higher molecular weight polymers and slower rates of polymer hydration are usually followed by enhanced floating behavior. The floating characteristics of all evaluated excipients were improved when simulated meal medium was used. Finally, the combination of resultant weight measurements and swelling experiments can be used to determine in vitro the buoyancy, weight and volume changes of orally administered dosage forms and to predict floating behavior.