Controlled release of adriamycin from silicone elastomer and its antitumor effects on Yoshida Sarcoma

Abstract

Adriamycin (ADM) -silicone elastomer composite which is a delivery system for an anticancer agent was developed by the authors to facilitate local cancer chemotherapy of recurrent and metastasized tumors and chemoembolization of primary tumors. The characteristics of ADM release from this composite and its antitumor effects on Yoshida sarcoma were investigated in this study.The ADM release in vitro was affected by the external fluids, the amount of ADM embedded in the sillicone elastomer, the surface area of the composite and the temperature of the external fluid, and it was enhanced significantly by the addition of glycine or D-mannitol to the silicone elastomer.After the inoculation of tumor cells the mean survival period of the 10 rats administered with the composite was more than 46.8 days and their rate of survival for 60 days was 40%. However, the survival period of the 10 rats without the composite was 8.5±1.3 days and all of them died in 10 day.Flow cytometric analysis showed that, in the tumor cells of the rats administered with the composite, more than 70% of the cells were in the G1 phase and the S, G2+M phase was decreased relatively. This tendency was seen for 5 days after the administration of the composite. Morphologically, vacuole formation, enlargement and the disappearance of mitosis of the tumor cells were observed. These results show that the antitumor effects of the composite actually remained for along time.