Active pharmaceutical ingredients or APIs can be defined as the chemicals used to manufacture pharmaceutical drugs. The active ingredient (AI) is the substance or substances that are biologically active within the drug and is the specific component responsible for the desired effect it has on the individual taking it.
Any drug or medication is composed of two components. The first is the API – which is the central ingredient. The second is known as the excipient, which is the inactive substance that serves as the vehicle for the API itself. If the drug is in a syrup form, then the excipient is the liquid that has been used to make it as such.
APIs are generally manufactured through a variety of processes that include:
- Chemical synthesis
- Fermentation processes
- Recombinant DNA
- Isolation and recovery from natural sources
- A combination of these processes
The purpose of APIs according to the FDA is to cause ‘pharmacological activity or other direct effects in the diagnosis, cure, mitigation, treatment or prevention of disease or to affect the structure and function of the human body.
There are however certain APIs that are unknown and so require additional substances that work in conjunction with the API to produce the required effect. This is very visible in herbal medicines in which the API is frequently a combination of several mixtures and/or substances which when used together cause pharmacological activity on the body. In these situations, the API is not a single substance but the culmination of various ingredients.
By drawing these distinctions between APIs and the drugs themselves, manufacturers are able to specialize and pharmacists able to align generic equivalents with brand names. This is of vital important and underlies one of the most solid principles and regulations of modern pharmacy.