Active Pharmaceutical Ingredient (API) is defined by U.S. Food & Drug Administration as: any substance or mixture of substances intended to be used as the active ingredient in the manufacture of a drug (medicinal) product. Such substances are intended to furnish pharmacological activity or other direct effect in the diagnosis, cure, mitigation, treatment, or prevention of disease or to affect the structure or function of the body. API may exist in the form of liquids, powders, crystals and extracts that obtained by chemical synthesis, plant extraction, or biotechnology and is not taken by patients directly. Only when API is processed into a pharmaceutical preparation, can the product be used for clinical use. The synthesis of APIs is usually a complicated and multi-step process involving numerous chemical transformations and operations on a range of raw materials with different physical and chemical properties. Specialized expertise is needed to achieve API synthesis.