Preparation and characterization of poly(lactic-co-glycolic acid) microspheres for targeted delivery of a novel anticancer agent, taxol.

This study describes the preparation and characterization of poly(lactic-co-glycolic acid) microspheres containing a novel anticancer agent, taxol (namely, Taxol-PLGA-MS). A solvent evaporation technique was utilized to prepare Taxol-PLGA-MS. The trapping efficiency of taxol in the microspheres was greater than 90% and reproducible. The in vitro release rate of taxol from the microspheres was very low, and less than 15% of the initial amount of taxol was released in three weeks, irrespective of the drug loading level. When a chemical additive, isopropyl myristate (IPM), was introduced at the level of 30% (w/w), the release of taxol increased significantly; approximately 70% of the initial amount of taxol was released at a nearly constant rate for three weeks. Elevation of the loaded IPM level to 50% (w/w) produced a more rapid release of the drug. Scanning electron microscopy showed that Taxol-PLGA-MS were spherical with a smooth surface. More than half (55-65%) of the microspheres had a diameter of 20-45 microns. Incorporation of IPM had no significant influence on the particle size, surface morphology, or degradation behavior of the microspheres. It was strongly suggested that the release of taxol from the microspheres was dominated mainly by the drug diffusion in the matrix. As evaluated from the particle size, drug content, and in vitro release property, IPM-containing Taxol-PLGA-MS may be suitable for chemoembolization therapy of cancer diseases.