More than 12,000 compounding pharmacies operate in the United States, and each year compounded product sales reach $300 million–25% of that is spent in the animal pharmaceutical industry alone. The Food & Drug Administration (FDA) has developed regulations to provide assurances for safety and efficacy of drugs and devices, to ensure food supply safety, and to regulate food chain supplies and animal foods; so how do these apply to compounding? At the 2010 American Association of Equine Practitioners (AAEP) Convention, held Dec. 4-8 in Baltimore, Md., Scott Stanley, PhD, professor of Equine Analytical Chemistry at the University of California, Davis, discussed FDA's ongoing attempts to ensure safety of drugs produced by compounding pharmacies (that provide individualized medications ordered by prescribers which are unavailable through normal means).

He described a study conducted by the FDA in which scientists analyzed 29 samples from 12 compounders. Stanley noted that 10 of the samples failed to meet the FDA standard for quality testing (which for potency is ±10% of the labeled concentration), yielding a 34% failure rate as compared to the typical 2% failure rate seen among the entire pharmaceutical industry in general. More than half of the failed samples contained less than 70% of the labeled potency.

Equine practitioners must evaluate the integrity of compounding pharmacies as well as the quality and consistency of drugs produced. Stanley remarked than many practitioners express concerns about efficacy of products that different compounding pharmacies compound, noting that just because a pharmacy prepares a product doesn't mean that it's efficacious–what an owner might perceive as a legitimate, reliable source of medication might not always be. In addition, veterinarians must consider the quality (potency, purity, and stability) and consistency of drugs as well as their liabilities for using that particular product.

Stanley explained that the FDA does not permit compounding, but rather uses "enforcement discretion," meaning that if a product cannot be obtained to control a life-threatening disease process or to control suffering, then use of a compounded product is permitted