Preparation and Properties of Poly(propylene carbonate maleate) Microcapsules for Controlled Release of Pazufloxacin Mesilate

A novel biodegradable aliphatic polycarbonate, poly(propylene carbonate maleate) (PPCMA) was synthesized by terpolymerization of carbon dioxide, propylene oxide, and maleic anhydride (MA), using a polymer supported bimetallic complex as catalyst. The utility of PPCMA to encapsulate and control the release of drug pazufloxacin mesilate (PZFX), via microcapsules, was investigated. PPCMA microcapsules containing PZFX were elaborated by solvent evaporation method based on the formation of double W/O/W emulsion. The manufacturing parameters such as the volume ratio of V(PPCMA) : V(PZFX), the concentration of stabilizer gelatin in outer aqueous phase played major roles on microcapsule characters, and were altered to optimize the process parameters. The PPCMA-PZFX microcapsules were obtained with smooth and spherical surface under optimum condition, the mean diameter of microcapsules was similar to 2 mu m, and the drug loading and drug encapsulation efficiency of the microcapsules were 22.9 +/- 1.05% and 82.1 +/- 2.03%, respectively. PZFX released from PPCMA microcapsules was found to reach 89.8 +/- 2.89% after 36d in a pH 7.4 phosphate-buffered solution, and the release profile obeyed the Higuchi equation. The results suggest that the new polymer PPCMA provides an alternative to degradable matrix polymers for long-term sustained releasing drug delivery systems. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 3248-3254, 2011