ABSTRACT
The aim of the prsent study was to compare the realibility of LD50 determination using the traditional Litchfield and Wilcoxon method with that obtained by forur alternative tests requiring smaller numbers of animals, for the purpose of classifyng chemicals according to their acute toxicity. Acute lethal dose determinations were carried out in mice for oral and intraperitoneal administration of hexachlorophene, lidocaine, methanol, phenobarbital and physostigmine. The Molinengo method proved not to be as reliable as suggested by its author. Determination of LD50 using the Thompson and Weil method or, alternatively, the maximal non-lethal dose and the approximate lethal dose permitted the classification of the chemicals in essentially the same order. The approximate lethal dose method, in particular, seems to be a very suitable alternative method to the classical LD50 test since it requires only about 6 animals, provides enough information to order chemicals according to their toxicities, and provides useful information for planning subsequent repeated-dose studies
Subject(s)
Mice , Animals , Male , Female , Animal Testing Alternatives , Lethal Dose 50 , Hexachlorophene/toxicity , Lidocaine/toxicity , Methanol/toxicity , Phenobarbital/toxicity , Physostigmine/toxicityABSTRACT
Foram estudados, comparativamente, os efeitos da aplicaçäo tópica de uma emulsäo comercial contendo hexaclorofeno a 3% em ratos recém-nascidos eutróficos ou desnutridos intra-útero, na primeira semana de vida. Os resultados indicaram alta mortalidade durante o tratamento, tendo os animais desnutridos intra-útero apresentado maior susceptibilidade aos efeitos da droga. O ganho ponderal foi menor durante a exposiçäo ao hexaclorofeno, ocorrendo recuperaçäo no restante do período de lactaçäo. O tratamento dos filhotes com hexaclorofeno alterou também o comportamento maternal das ratas eutróficas que os amamentavam