A sponsor must first submit data showing that the drug is reasonably safe for use in initial, small-scale clinical studies. At the preclinical stage, the regulatory body will generally ask, at a minimum, that sponsor provides:
- a pharmacological profile of the drug
- acute toxicity of the drug in at least two species of animals
- short-term toxicity studies ranging from two weeks to three months, depending on the proposed duration of use of the substance in the proposed clinical studies.
Animal assess the general pharmacology and mechanisms of action of drugs.
The main objective is to understand the effects of a novel chemical entity in a complex organism and to predict the new drug’s behavior in humans. A large number of parameters is assessed, e.g. absorption, distribution, metabolism, and excretion (ADME), bioavailability, protein binding, stability and half-life, maximum serum concentration, total exposure or area under the curve, clearance, volume of distribution, drug-drug interactions, onset of drug action as well as multicompartmental analysis of blood, liver, and other tissues. These studies are an integral part of lead optimization. They feed back into lead optimization to optimize the physicochemical properties of new leads in terms of minimal toxicity and side effects, as well as of maximum efficacy toward disease.