If preclinical testing is successful, the drug moves into clinical trials. This phase is divided into four stages:
1. Phase I: Tests the drug on a small group of healthy volunteers or patients to assess safety and dosage. 2. Phase II: Focuses on the effectiveness of the drug, involving a larger group of patients who have the disease. 3. Phase III: Involves an even larger patient group to confirm the drug's effectiveness, monitor side effects, and compare it to standard treatments. 4. Phase IV: Post-marketing surveillance to monitor long-term effects and ensure ongoing safety.
