Crosslinked Poloxamers as a Versatile Monolithic Drug Delivery System

Abstract

There is growing interest in the development of homogeneous monolithic drug release systems for various routes of administration. One very attractive type of such dosage forms is based on hydrophilic water-swellable polymers which generally exhibit high biocompatibility. On contact with an aqueous liquid (dissolution medium or gastrointestinal fluid) the polymer swells. Liquid penetrates into the system and drug is released by counter-current diffusion. Depending on the physical characteristics of the polymer, different thermodynamic transitions such as glass-to-rubber transition of the amorphous zones or melting out of crystallites may occur during liquid penetration. These thermodynamic reactions might be responsible for the drug release kinetics not showing square-root-of-time dependance^1–5.