ABSTRACT
In the broadest terms, all of what is done in preclinical (and, indeed, in Phase I clinical) studies can be considered a form of screening [1]. This is certainly true of safety pharmacology studies. What varies is the degree of effectiveness of (or our con˜dence in) each of the tests used. As a general rule, even though we think of the expensive and labor-intensive “pivotal” studies required to support regulatory requirements (4-week to 1-year toxicity studies, carcinogenicity, and segment I-III studies, etc.) as de˜nitive, in fact, they are generally effective but not necessarily ef˜cient screens.
