The results of cytotoxicity tests in primary cultures of rat hepatocytes and in MDBK and McCoy cells can be used to predict the in vivo 4-wk maximum tolerated dose in rats and dogs. A correlation between in vitro cytotoxicity, as measured in this system, and LD50 values in rats and mice has also been established. - [Read In Vitro Prediction of the Maximum Tolerated Dose Protocol]