365: Chemistry for Life
DAY 22

Excipients

King James I charters the first English organization of pharmacists, 1617, long before these inactive ingredients in medicines could help drug delivery.

Credit: iStock

When you take a pill, it’s not all medicine. It says so right there on the box of your over-the-counter drug—if you are self-medicating—or in the fine print of the patient information sheet for your prescription drug. The listing typically includes some peculiar names: sodium starch glycolate, dibasic calcium phosphate, crospovidone, magnesium stearate, carboxymethylcellulose, methylparaben, and so on. So what is all that stuff?

The answer is “excipients.” These are the inactive ingredients that help hold a dose of the active pharmaceutical ingredient (API) together and keep it stable for a long shelf life. Excipients also can serve to mask an unpleasant taste or texture and help ensure that the right amount of the API makes it to the right spot in the body at the right time. Whether it is a tablet, gelcap, liquid, cream, suppository, patch, injection, or inhalant, all medicines contain several excipients—and every one of them is there for a good reason.

Excipients are nothing to sneeze at, mind you. The global market value for this class of chemicals was $3.5 billion in 2006, according to an industry report by BCC Research. The market value is expected to reach $4.3 billion in 2011.

FDA has approved several hundred additives for medicines, with most of them aimed for use in making tablets and capsules. There are 40 official categories, including acidifying agents, antifoaming agents, buffering agents, emulsifying agents, antioxidants, pigments, and dessicants.

Visit “What’s That Stuff” to read more about excipients.

Excerpted with permission, Chemical & Engineering News
Copyright © 2008 American Chemical Society