Preparation of camptothecin-loaded PCEC microspheres for the treatment of colorectal peritoneal carcinomatosis and tumor growth in mice

The aim of this study was to prepare PCL–PEG–PCL (PCEC) microspheres to protect camptothecin from hydrolysis, to extend its release time and to enhance its treatment efficacy on colorectal peritoneal carcinomatosis and tumor growth in mice. Camptothecin (CPT)-loaded PCL–PEG–PCL (PCEC) microspheres were prepared by oil-in-water emulsion solvent evaporation method. The particle size, morphological characteristics, encapsulation efficiency, in vitro drug release studies and in vitro cytotoxicity of CPT-loaded PCEC microspheres have been investigated. In vivo studies were carried out on Balb/c male mice bearing colorectal peritoneal carcinomatosis. CPT-loaded PCEC microspheres were applied to abdominal cavity of mice once a week. Free CPT was used as a positive control. On 14th day of treatment, mice were sacrificed and antitumor activities of CPT-loaded PCEC microspheres were evaluated. Compared with control group, a significant decrease in the number of tumor nodes was observed in group treated with CPT-loaded PCEC microspheres. Immunohistochemistry staining of tumor tissues with CD34 revealed that MVD positive cells were significantly reduced in CPT-loaded PCEC microspheres treated group in contrast to other groups (P < 0.05). The CPT-loaded PCEC microspheres were considered potentially useful to treat the abdominal metastases of colon carcinoma.