Final answer:
The phases of human testing for new pharmaceutical drugs begin with Phase I, where safety and pharmacokinetics are assessed in healthy volunteers. Phase II tests efficacy and dosage in patients with the disease. Phase III expands the testing to a diverse group of participants, and Phase IV explores additional uses post-approval.
Step-by-step explanation:
The process of clinical trials for a new pharmaceutical drug involves several phases of human testing. After pre-clinical tests, which include in vitro and animal tests, clinical trials with human participants begin. The FDA and other regulatory bodies such as the EMA have set guidelines for each phase for drug approval. Here are the phases of human testing organized in the correct order:
- Phase I: The drug is tested on healthy human volunteers to assess toxicity. This is to ensure the drug is safe and to determine the pharmacokinetics, such as absorption and elimination rates. Multiple dose studies follow and if not well-tolerated, it may be dropped from development.
- Phase II: The drug is tested in the target human population, in patients that have the particular disease or disorder. This involves dose-ranging studies to establish effective dosage for phase III trials.
- Phase III: The drug is tested in many centers to maximize the number of test participants, including different sexes and ethnic groups, for a larger and diverse patient database, and to assess efficacy and safety.
- Phase IV: Post-approval, the drug is tested for other potential uses beyond the original intended treatment.