Food and Drug Administration's requirements for markers

Three basic principles must be satisfied when a substance is being considered for human ingestion: The composition of the product must be consistent within certain limits over a specific period of time. It must not produce irreversible harm or unacceptable side effects. When taken as indicated, it must produce the effect that is claimed and intended. Specific requirements for markers will depend on the marker selected. There are regulations for use of radioactive substances as tracers in drugs. Markers might also be subject to regulations for a new drug or combination drug or might be a substance generally recognized as safe. If the marker is included as an excipient in the drug, the associated requirements for excipients would apply. Any assay methods for detecting the marker must be validated.