Abstract
The thalidomide tragedy stimulated an intense research in the etiology, prevention and treatment of congenital malformations. The Government requires that drugs and food additives be evaluated pre-clinically for toxicity, including developmental toxicity, before being marketed. The number of compounds which must be tested has increased dramatically with the continuous development of therapeutic, cosmetic and food additive chemicals. Such tests include: in vitro studies which can serve as efficient pre-screens to rank chemicals for further batteries of in vivo tests on pregnant animals. However, the safety of any drug would be determined only by a post-marketing epidemiological survey. Taking into account the altered susceptibility to different drugs in a pregnant individual, it could be said that administration of any drug during the first trimester is an experiment in human teratology.
Highlights
The aim of developmental toxicology is to detect any adverse effects of xenobiotics on the pregnant female and on the development of the embryo and foetus as a consequence to exposure from starting with implantation through the entire period of gestation, parturition and maturation
Many mechanisms exist by which chemicals can cause birth defects, but the critical insult which accounts for the adverse effect on the embryo is known for only a few chemicals (Tab. 1)
It has been possible in the mouse, rat and rabbit to demonstrate teratogenic activity by all substances that have been shown to be teratogenic in humans, there is no absolute assurance that negative results obtained by testing drugs in these species can be used to predict that an agent will lack teratogenic effects in humans
Summary
The aim of developmental toxicology is to detect any adverse effects of xenobiotics on the pregnant female and on the development of the embryo and foetus as a consequence to exposure from starting with implantation through the entire period of gestation, parturition and maturation. Clinical proof that chemical agents can induce birth defects in the human species existed before the thalidomide disaster. Some 10 years earlier, the drug aminopterin, given in high abortifacient doses, caused multiple malformations in abortuses[3]. Assessment of the potential for developmental toxicity has been identified as one of the key areas to be considered in the evaluation of the safety of new drugs. Before 1960, governmental recommendations given for testing chemicals during the reproductive cycle of animals were conventional 6 weeks chronic toxicity test in male and female rodents followed over two pregnancies.
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Schedule a callMore From: Biomedical papers of the Medical Faculty of the University Palacky, Olomouc, Czechoslovakia
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