Drug development is a long, expensive, and high-risk process that takes an average of 10-15 years. It involves preclinical research in animals and humans to test safety and efficacy. Clinical trials in humans have 4 phases - Phase I tests safety in small groups, Phase II explores efficacy in small patient groups, Phase III tests in large patient groups to confirm efficacy and safety for approval, and Phase IV occurs after approval to monitor long-term effects. Only about 1 in 10 drugs that enter clinical trials will ultimately receive regulatory approval due to the high costs and failure rates of drug development. Rigorous testing and regulatory review are required to bring a new drug to market globally.