API (Active Pharmaceutical Ingredient) API is a well-defined definition in ICH Q7A: any substance or mixture of substances intended for use in the manufacture of pharmaceuticals, and when used in pharmaceuticals, becomes an active drug. ingredient. Such substances may have pharmacological activity or other direct effects in the diagnosis, treatment, symptom relief, treatment or prevention of diseases, or may affect the function or structure of the body. Refers to the raw materials used in the production of various preparations, which are the active ingredients in the preparations, which are prepared by chemical synthesis, plant extraction or biotechnology. They are used as medicinal powders, crystals, extracts, etc., but patients cannot take them directly. Substance. The active ingredient of the medicament. The raw material medicine can only become a medicine for clinical application if it is processed into a pharmaceutical preparation. According to its source, APIs are divided into two major categories: chemical synthetic drugs and natural chemical drugs. Chemical synthetic drugs can be further divided into inorganic synthetic drugs and organic synthetic drugs. Inorganic synthetic drugs are inorganic compounds (very few elements), such as aluminum hydroxide and magnesium trisilicate for the treatment of gastric and duodenal ulcers; organic synthetic drugs are mainly composed of basic organic chemical materials, through a series of organic Drugs produced by chemical reactions (such as aspirin, chloramphenicol, caffeine, etc.). Natural chemical drugs can be divided into biochemical drugs and phytochemical drugs according to their sources. Antibiotics are generally produced by microbial fermentation and belong to the category of biochemistry. A variety of semi-synthetic antibiotics that have emerged in recent years are products that combine biosynthesis and chemical synthesis. Among the APIs, the proportion of organic synthetic drugs, the output and the output value are the largest, which is the main pillar of the chemical pharmaceutical industry. The quality of raw materials determines the quality of the preparations. Therefore, the quality standards are very strict. Countries around the world have established strict national pharmacopoeia standards and quality control methods for their widely used APIs.