Enhanced anticancer efficacy by use of mitomycin C adsorbed on small activated carbon particles in mice

A new dosage form of mitomycin C (MMC-CH) was tested for toxicity and therapeutic efficacy against intraperitoneally inoculated cancer cells in mice. MMC-CH is a suspension comprising 7.16 mg/ml of activated carbon particles, 1 mg/ml of mitomycin C (MMC) and 20 mg/ml of polyvinylpyrrolidone in saline. The LD50 value determined by means of the Litchfield-Wilcoxon method after intraperitoneal administration was 2.29 times higher for MMC-CH than for MMC aqueous solution. Mice were inoculated intraperitoneally with 2 X 10(5) P388 leukemia cells and given an intraperitoneal injection of 10 to 1.25 mg/kg of MMC in the form of MMC-CH or MMC aqueous solution 24 hr after the inoculation. The median survival time was prolonged to 270.5%, 223.0% or 168.3% by MMC-CH at the dose equivalent to 10, 5 or 2.5 mg/kg of MMC, respectively, while it was prolonged to 182.7%, 139.6% or 155.4% by MMC aqueous solution at the dose of 5, 2.5 or 1.25 mg/kg of MMC, respectively, as compared with the median survival time in the non-treated group. MMC-CH prolonged the survival time to more than 120% as compared with the same dose of MMC given as MMC aqueous solution, and was less toxic.