Animal Model Systems Suitable for Controlled Release Modeling

Abstract

Studies in animals are far more accessible than human studies and they are less expensive. Setup and data generation are much shorter and animal studies can be attractive as a preclinical option to guide dosage form design of controlled release formulations. However, differences in gastrointestinal (CV) anatomy, environmental conditions in the GI tract and other factors that can affect release, absorption and drug metabolism can lead to confounding, as well as nonpredictive findings. There is far greater potential for baffling findings than in the case of conventional immediate release (IR) formulations. It is vital therefore to be aware of interspecies differences, as well as human–animal differences so that the most appropriate species is chosen for testing specific drug formulations and that findings are carefully interpreted with respect to their relevance to performance in humans. This chapter presents and discusses the anatomical, physiological and metabolic differences that can be encountered in a range of animals and the possibilities and limitations of such testing of controlled release formulations.