Some aspects of pharmacokinetic and biotransformation differences in humans and mammal animals.

The erroneous tendency to set pharmacokinetics and biotransformation of drugs in man against results obtained in animals as a different homogenous group is discussed. Species differences have mainly a quantitative character, such as the body weight to surface ratio, organ weight to body weight ratio, presence of differing fat deposits, etc. Qualitative differences are not so common. The great importance of a better knowledge of these problems for the prediction of drug effects in man from results obtained in animals is emphasized.