Pre clinical Trails

Preclinical Trails are done before Clinical Trails started.
These include Invitro Trails
Invivo Trails

Invitro Trails They are for genotoxicity studies by using Salmonella typhi TA 98, TA 100, TA 1535 to detect mutagenicity of the test Drug.If the test drug is having mutagenicity test drug increases the number of Histidine revertants.It is carried out with or without S9 enzyme(Metabolic activation enzyme extracted from liver).This is Popularly called Ames Test.

and also we can use E.Coli for Genotoxicity.

Chinese hamster ovary cells are also used for Genotoxicity studies.

Invivo Trails for Safety,to demonstrate the Test Drug is useful to treat certain Disease.
usually done in rats,monkeys

So by using preclinical trails we can get the data of safety and efficacy of Test Drug at Certain extent inorder to confirm we need to do human clinical trails.Then the sponsor applies FDA with IND application.