In purchasing drugs and supplements, I've noticed that certain products are advertised as Pharmaceutical Grade. Wanting to know what qualifies a substance as pharmaceutical grade I did some googling and found the USP, which apparently sets drug purity standards for the FDA. But in visiting the USP website I find a USP dictionary will set me back $378.00. And the Reference Standards seems to be a comprehensive list of drugs, but instead of providing any useful info, each one is listed as a product that I can purchase for several hundred dollars.

openFDA label database doesn't seem to include any information on purity standards, just standard doses and dosages.

I'm incredulous that the definition of Pharmaceutical Grade for any given substance adopted by the FDA should be a secret I have to pay nearly $400 to learn. So my question is, is there some source I'm missing, either within, or outside openFDA?

  • This sounds like it may be similar to the situation for building codes. Carl Malamud has been fighting for them to be freed for a while, but it's not something that gets a lot of people fired up. Mar 25, 2015 at 18:12

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I found a definition from the NIH site related to humans and other animals. (PDF link)

Pharmaceutical-grade compound: A pharmaceutical-grade compound (PGC) is defined as any active or inactive drug, biologic or reagent, for which a chemical purity standard has been established by a recognized national or regional pharmacopeia (e.g., the U.S. Pharmacopeia (USP), British Pharmacopeia (BP), National Formulary (NF), European Pharmacopoeia (EP), Japanese Pharmacopeia (JP), etc.). These standards are used by manufacturers to help ensure the products are of the appropriate chemical purity and quality, in the appropriate solution or compound, to ensure stability, safety, and efficacy. The Food and Drug Administration (FDA) maintains a database listing of FDA approved commercial formulations for both FDA approved human drugs (the Orange Book) and veterinary drugs (the Green Book).

  • Thanks for the effort, but what you quote simply says 'for every drug, we keep a purity standard somewhere and call it pharmaceutical-grade'. It doesn't give any information on, or public source for what the purity standard actually is. The Green Book and the Orange Book give information on strength but not purity. If some drug x is approved at 5% strength, what was the purity of the source for the active ingredient before it was diluted? It's going to be different for different substances with different isolation and purification methods. Oct 31, 2014 at 1:30

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