Phases of the clinical trials are the categories that are processed to determine if any new drug or device can be approved for use in the future. Mainly, there are four phases:
• Phase I : This phase includes testing of an experimental drug, vaccine or device in a small group of people for evaluating the safety, side effects and determining the safe dosages.
• Phase II : This involve a larger group of people than Phase I and are designed to assess whether the experimental treatment is safe and determines whether it will work or not. It can last several years.
• Phase III :This phase involves large studies for comparing the experimental drug or vaccine to a placebo or standard treatment. This phase evaluates whether the drug works and collect information to allow it to be used safely.
• Phase IV :This phase is performed once a drug has reached the market and is to provide additional information about the best use of the drug.