Preclinical testing is a crucial stage in drug development and involves evaluating the efficacy and safety of a potential new drug before it is tested on humans in clinical trials. This phase typically involves testing the drug on laboratory animals, such as mice or rats, to assess its pharmacokinetics, toxicity, and potential side effects. Preclinical testing also includes in vitro studies to understand the drug's mechanism of action and its effects on cells or tissues. The goal of preclinical testing is to gather sufficient evidence to support the safety and efficacy of the drug before it is tested on human subjects.