Using In Vitro Data to Estimate In Vivo Starting Doses for Acute Toxicity 2.0 ELEMENTS OF A STANDARD TEST FOR BASAL CYTOTOXICITY

It is likely that many different in vitro cytotoxicity methods could be used to help select the in vivo starting dose for an acute lethality assay. Two decades of experience indicate that in vitro basal cytotoxicity data determined in various primary cells, as well as in various permanent nondifferentiated finite or transformed cell lines, generally show comparable cytotoxic concentrations of the same xenobiotic, regardless of the type of toxic endpoints investigated. The RC data, which consist of information from many different in vitro methods that vary in both cell type and cytotoxicity endpoint (i.e., specific protocol), indicated that exceptions to this “rule” were observed only for those chemicals (some insecticides, neurotropic chemicals, and chemicals requiring metabolic activation) that require specific cell types to express their toxicity (Halle, 1998). Thus, a recommendation cannot be made for the "most relevant" or "most typical" in vitro test for basal cytotoxicity.