Cisplatin microcrystals suspended in oil—toxicity in mice

A new dosage format, cisplatin microcrystals suspended in oil (CDDP-oil), was developed for the treatment of peritoneal carcinomatoses. We studied the acute toxicity of CDDP-oil injected intraperitoneally in mice. The 50% lethal dose was 30.3 mg/kg (27.1–33.7 mg/kg at the 95% confidence level), which was 1.79 times that of a cisplatin aqueous solution (CDDP-sol) of 16.9 mg/kg (16.1–17.8 mg/kg at the 95% confidence level). There were no significant differences in the duration of the toxic effects and the toxic symptoms between these two dosage forms. However, the severity of weight loss in the group given CDDP-oil was less than the group given CDDP-sol.