What Are Active Pharmaceutical Ingredients, or APIs?

Pharmacist in pharmacy
Echo/Getty Images

Defined as briefly as possible, active pharmaceutical ingredients are the chemicals in drug products that make the medications work. That definition is nowhere near as simple as it sounds.

Drawing distinctions between APIs and drugs makes it possible for manufacturers to specialize, regulators to focus resources, and pharmacists to align generic equivalents with brand name products. Understanding what makes an API an API, and why having that understanding matters, underlies the very practice and regulation of pharmacy.

APIs According to the FDA and the WHO

Very specifically, APIs are chemicals used in everyday prescription and over-the-counter medications. Biologically engineered proteins and recombinant molecules created for biotech drugs fall under different definitions and regulatory schemes.

The U.S. Food and Drug Administration defines an APIs as

any substance or mixture of substances intended to be used in the manufacture of a drug product and that, when used in the production of a drug, becomes an active ingredient in the drug 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 and function of the body.

The World Health Organization has developed a nearly identical API definition. The WHO’s definition was under review as of September 2012, however. Many international authorities believe that a mixture of APIs actually constitutes a finished pharmaceutical product, which would be a medication of the type the FDA refers to as a “drug product.”

Drug products—which is to say, the medications pharmacists dispense and patients use—include one or more API, excipients and other ingredients ranging from dyes to alcohol and water.

Who Makes APIs?

APIs are often referred to as “bulk pharmaceuticals,” and the chemicals usually get made in plants far removed from the facilities where tablets, oral suspensions, and topical applications are made.

Produced in bulk, almost all APIs are powders.

Chemical plants in every country make bulk pharmaceuticals, but the leading suppliers of APIs cluster in China and India.

Regardless of where an API gets made, it must meet the safety and quality standards set by the leading drug regulator in the country where it will be used. That is, Chinese and Indian bulk drug manufacturers that export chemicals to the United States must be inspected and licensed by the FDA. Likewise, bulk pharmaceuticals produced for many countries in Europe are subject to standards established by the European Medicines Agency.

Regularly inspecting and, when necessary, sanctioning chemical makers outside the country can prove difficult. Counterfeiting, adulteration, and contamination remain constant concerns with APIs imported into the United States and elsewhere. Since 2008, the FDA has been expanding its overseas staff charged with overseeing bulk pharmaceutical manufacturers.

The Generic Name Is the API

The last thing to know about APIs is also the first thing, with a twist.

Bulk pharmaceuticals themselves are not generic drugs, but the API in Pfizer’s Lipitor and each of its generic equivalents is atorvastatin. As noted above, making atorvastatin into a drug product requires adding other ingredients to form tablets.

It is absolutely essential, however, that pharmacists and pharmacy technicians know the identity of each drug’s API because the name of the API is the generic name of the medication. Two conventions—United States Adopted Names and International Nonproprietary Names—help ensure each API has a unique identity. When the FDA approves a new drug, the agency requires a generic name for the product that meets USAN/INN criteria. That generic name stays with the brand name product and becomes the name of all equivalent generic drug products subsequently approved.

Pronunciation: ay-pee-eyez

Also Known As: APIs, bulk pharmaceuticals

Continue Reading