ABSTRACT
Time, Costs, Animal Use, and Testing Capacity In the early 1960s, the original designers of developmental toxicity testing protocols presumably were more concerned that another “thalidomide” did not slip through undetected than they were about time, costs, and animal use. To ensure the detection of teratogenic agents, they specified testing in two species (mainly rats and rabbits) and the use of large sample sizes (Table 24.2). When one considers preliminary dosefinding studies that are also conducted in pregnant animals of both species, the number of animals used to test just one compound amounts to about 250 adult females and almost 2500 fetuses. This constitutes approximately 22% of the total number of animals used in a standard mammalian toxicology testing package as required to register a drug or pesticide and does not include reproductive or juvenile toxicity studies, which constitute another 40% or more of the animals used in a standard mammalian toxicity testing package (3,4).
