5-Fluorouracil-loaded chitosan coated polylactic acid microspheres as biodegradable drug carriers for cerebral tumours.

The development of injectable microspheres for anticancer drug delivery into the brain is a major challenge. The possibility of entrapping 5-fluorouracil (5-FU) in chitosan coated monodisperse biodegradable microspheres with a mean diameter of 10-25 um was demonstrated. An emulsion of 5-FU (in water) and polylactic acid (PLA) dissolved in acetone-dichloromethane mixture was poured into an aqueous solution of chitosan (or poly-vinyl alcohol) with stirring using a high-speed homogenizer, for the formation of microspheres. 5-FU recovery in microspheres ranged from 44-66% depending on the polymer and emulsification systems used for the preparation. Scanning electron microscopy revealed that the chitosan coated microspheres had less surface micropores compared to PVA based preparations. The drug release behaviour from microspheres suspended in phosphate buffered saline exhibited a biphasic pattern. The amount of drug release was much higher initially (approximately 25%), followed by a constant slow release profile for a 30 days period of study. This chitosan coated PLA/PLGA microsphere formulation may have potential for the targeted delivery of 5-FU to treat cerebral tumours.