Evaluation of cis-diamminedichloroplatinum(II) combined with metoclopramide or sodium thiosulfate on L1210 leukemia in vitro and in vivo

A microtiter assay was developed to monitor cytotoxic activity of drugs alone and in combination at varying ratios on a single plate. Combinations of metoclopramide or sodium thiosulfate with cis-diamminedichloroplatinum(II) (cisplatin) were evaluated in vitro and in vivo for cisplatin cytotoxicity to murine leukemia L1210. The in vitro assay indicated that metoclopramide did not interfere with cisplatin-induced cytotoxicity and confirmed previously reported inhibition of cisplatin activity by sodium thiosulfate. The drug combinations were also evaluated in vivo for antitumor activity and the results of these studies corroborated the in vitro results.