A Diffusion Controlled Drug Delivery System for Theophylline

The goal of achieving ideal attributes of a drug delivery system including reliability and predictability has led investigators to design controlled release (CR) systems based on the principles of microporous coatings, diffusion controlled coatings and various hydrogel type systems.

In this study, the critical role of “water content fraction” of a polymer in deciding its diffusion characteristics has been ascertained and the correlation between molecular size/shape, membrane thickness, pore radii and drug diffusion has also been demonstrated. The theoretical considerations, designing and engineering of a “barrier coated-reservoir” type of a delivery system for theophylline using poly (vinyl alcohol) PVA] as the coating material are discussed. After realizing the desired theoretical in-vitro release profile, in-vivo studies were carried out on a dog model. The potential of poly (vinyl alcohol) as a barrier coating material in developing a CR system is interestingly observed.