Understanding active pharmaceutical ingredients
Active pharmaceutical ingredient (API), is the term used to refer to the biologically active component of a drug product (e.g. tablet, capsule). Drug products are usually composed of several components. The aforementioned API is the primary ingredient. Other ingredients are commonly known as "excipients" and these substances are always required to be biologically safe, often making up a variable fraction of the drug product. The procedure for optimizing and compositing this mixture of components used in the drug is known as "formulation". For example, if the API is a solid and the drug is required to have a liquid dosage form, such as a cough syrup, then the excipients would be the liquids that are used to formulate the syrup. The design criteria for any small molecule API is usually a combination of several factors that goes beyond the intended therapeutic effect, and usually heavily encompasses both pharmacokinetic and pharmacodynamic...