Latin for “within the living”; refers to experiments or procedures done inside a living organism. It is common practise that once an experiment works well in vitroLatin for "in glass"; refers to experiments or procedures done outside of a living organism, typical it moves on to an in vivo model. Such models can include mouse models, which are frequently used to test drug responses. Whole organism models are more complex and similar to a human compared with smaller scale experiments in the lab, therefore they provide greater evidence and support for the experimental hypothesis. Until 2022, preclinical animal testing was required for all FDA regulated clinical trials prior to testing investigational medical products in humans. In December 2022, a US bill was passed allowing the FDA the option to approve drugs tested preclinically in non-animal studies, such as in vitroLatin for "in glass"; refers to experiments or procedures done outside of a living organism, typical and in silico models.
