The use of in vitro methods for studying drug metabolism to replace animal studies as part of veterinary medicines product licence applications.
It is currently necessary to carry out drug metabolism studies in the target species as part of veterinary Product Licence Applications (PLA). Such studies use large numbers of animals. Studies with pig and rat liver homogenates obtained from animals slaughtered for human consumption have demonstrated that antipyrine shows the same metabolic differences between these species as would be expected in vivo. Continuation of these studies in sheep liver homogenates demonstrated species differences in the metabolism of antipyrine between sheep and pigs. In addition, ruminant isolated cell systems have been used to demonstrate differences in sulfadimidine metabolism between rats, goats, sheep and cattle. With the increasing availability of farm-animal isolated hepatocyte systems and mounting evidence that species differences in vitro reflect the in vivo situation, the time is right for such data to be submitted as part of veterinary medicine PLA.
Shaw
I C
IC
Centre for Toxicology, University of Central Lancashire, Preston PR1 2HE, UK.