The use of unallowed excipients.

The laws governing the U.S. Food and Drug Administration (FDA) do not provide for the approval of stand-alone excipients. Current regulations do not permit the use of excipients, but allow their use. The acceptance process for excipients is slow and only recently did the FDA propose draft guidance for nonclinical studies for pharmaceutical excipients. The FDA has made four suggestions to the U.S. Pharmacopoeia concerning including excipient monographs in the National Formulary for excipients not yet allowed. This article reviews these four proposals to identify the proposal that is most appropriate.