Editing Animal testing (section)

===Drug testing===
Before the early 20th century, laws regulating drugs were lax. Currently, all new pharmaceuticals undergo rigorous animal testing before being licensed for human use. Tests on pharmaceutical products involve:
* ''metabolic tests'', investigating [[pharmacokinetics]]—how drugs are absorbed, [[Drug metabolism|metabolized]] and [[Excretion|excreted]] by the body when introduced [[wikt:oral|orally]], [[intravenous]]ly, intraperitoneally, [[intramuscular]]ly, or [[Transdermal patch|transdermally]].
* ''toxicology tests'', which gauge [[acute toxicity|acute]], sub-acute, and [[chronic toxicity]]. Acute toxicity is studied by using a rising dose until signs of toxicity become apparent. Current European legislation demands that "acute toxicity tests must be carried out in two or more mammalian species" covering "at least two different routes of administration".<ref name="32001L0083">{{CELEX|32001L0083|text=Directive 2001/83/EC of the European Parliament and of the Council of 6 November 2001 on the Community code relating to medicinal products for human use}}, sub II. PERFORMANCE OF TESTS, A. Toxicity</ref>{{rp|1. Single dose toxicity}} Sub-acute toxicity is where the drug is given to the animals for four to six weeks in doses below the level at which it causes rapid poisoning, in order to discover if any toxic [[drug metabolism|drug metabolites]] build up over time. Testing for chronic toxicity can last up to two years and, in the European Union, is required to involve two species of mammals, one of which must be non-rodent.<ref name="32001L0083"/>{{rp|2. Repeated dose toxicity (sub-acute or chronic toxicity)}}
* ''efficacy studies'', which test whether experimental drugs work by inducing the appropriate illness in animals. The drug is then administered in a [[Randomized controlled trial|double-blind controlled trial]], which allows researchers to determine the effect of the drug and the [[Dose response|dose-response]] curve.
* Specific tests on ''reproductive function'', ''embryonic toxicity'', or ''carcinogenic potential'' can all be required by law, depending on the result of other studies and the type of drug being tested.