Paclitaxel release from micro-porous PLGA disks

Micro-porous biodegradable polymeric foams have potential applications in tissue engineering and drug delivery systems. A two-stage fabrication process combining spray drying and supercritical gas foaming is presented for the encapsulation of paclitaxel in micro-porous PLGA (poly lactic glycolic acid) foams. Encapsulation of paclitaxel in the PLGA polymer matrix was achieved and these foams have potential application as a new type of surgical implant for controlled release of paclitaxel. This technique may also be applied to other hydrophobic drugs which face problems of slow release when encapsulated in a compact polymeric device. The micro-porous structure helps to increase drug release rate due to a shorter diffusion path of the drug in the polymer. The final residual organic solvent content in the polymer was low and well within safety limits due to the high miscibility of supercritical CO2 with the organic solvent. The pore size distribution, the phase behavior, and the in vitro swelling behavior of the foams were characterized. In vitro release results showed a nearly constant release rate for up to 8 weeks. The release profiles from micro-porous foam and from compressed disks were compared to assess the performance of micro-porous foams as sustained release implants. The foams implanted intracranially in mice showed therapeutic concentrations of paclitaxel at distant regions of the brain even after 28 days of implantation.