Morphology of the designed biodegradable cisplatin microsphere.

We observed the morphological changes in microspheres containing cisplatin (CDDP) embedded in poly-d,l,-lactic acid (PLA) and polyethylene glycol acid (CDDP-PPMS). The in vitro release of CDDP from CDDP-PPMS continued for more than four weeks. Scanning electron microscopy revealed that though the particles of CDDP-PPMS were spherical and superficially smooth, small pores with a superficial irregularity appeared six months later. CDDP-PPMS particles were found in the stomata of the omentum after intraperitoneal administration. When CDDP-PPMS was administered after Yoshida sarcoma cells were intraperitoneally transplanted, CDDP-PPMS was observed histologically in the necrotic tissues of the omentum. These experimental results confirmed the release of CDDP from CDDP-PPMS and the histological efficacy of CDDP-PPMS in the omentum against peritoneal metastasis.