In the context of the pharmaceutical industry, API stands for Active Pharmaceutical Ingredient. It refers to the biologically active component in a drug product that produces the intended therapeutic effect. APIs can be derived from natural sources or synthesized chemically. They are the key components that make a drug effective in treating a particular disease or medical condition. Once an API is identified, pharmaceutical companies can develop it into a drug product by adding other inactive ingredients, such as excipients, to make it stable, safe, and effective for patients. APIs are subject to strict regulations and quality control measures to ensure their purity, potency, and safety for use in pharmaceutical products. They are also tested extensively to ensure their efficacy and consistency in delivering the intended therapeutic effect.