Friday, March 14, 2008

What is pharmaceutical grade (USP)?

The US Pharmacopeia (USP) publishes official monographs for certain substances. These monographs include specific assay methods and product specifications to assure identity and potency. Material that is tested by these methods to meet those specifications is then eligible to be called pharmaceutical grade, or USP. The key concept is "standards and verification" Many natural ingredients do not have published USP monographs, so cannot be called USP grade (as there are no USP specifications or standards to test against). Also, the testing is often a bit imprecise, so a test result for purity may be acceptable within a narrow range (from 98% - 101% of label potency, for example) and still be considered good. Another standard monograph is that found in the Food Chemicals Codex, desribing FCC food grade materials. A product with an FCC monograph can be tested to meet the food grade specifications that are typically less rigorous than those in a pharmaceutical monograph, but do provide standards for purity and identity. Some substances have both USP and FCC monographs and can claim both grades. For example, the amino acid l-arginine has monographs in both compendia, as do some other aminos.


Anonymous said...

So is "pharmaceutical grade" dietary supplement the same as a "USP verified dietary supplement"? I had been led to believe the tolerances are much looser (20-30%) for supplements not labeled as "pharmaceutical grade"?

Neil E. Levin, CCN, DANLA said...

No, they are different. But it is confusing because the USP folks chose to lend its name to a completely different type of testing program.

Pharmaceutical grade raw material used to make dietary supplements has been tested and has passed the tests using procedures designated in a pharmaceutical monograph. Compliance to the specifications of the US Pharmacopeia monographs designate what can be called USP material. There can be a range of purity given for test results of pharmaceutical grade materials, such as 97-102%. The testing has an inherent range of inaccuracy, but rarely more than a few percent. And there are not USP monographs for every ingredient; any ingredients that lack this document cannot properly be called pharmaceutical grade.

On the other hand, USP-verified is a third-party testing program for finished dietary supplements (versus ingredients) that is not really claiming to be all pharmaceutical grade materials. Supplements use other ingredients for formulas or even as excipients, which dilute the material even if it were USP grade to start. As a result, the finished product is not called pharmaceutical grade unless there is also a pharmacopeia monograph for that finished product.

FCC (Food Codex) is another quality term for food grade material. For example, some amino acids have no USP monograph but do have an FCC monograph, so you get food grade rather than pharmaceutical grade material as the purest available.

Anonymous said...

If a person asks you for the USP monograph for testing a product, what are they asking for? Is it expressed as a number or is it the limits the test results can be? What exactly do they want?

Neil E. Levin, CCN, DANLA said...

The US Pharmacopeia is a collection of USP monographs that literally define what pharmaceutical grade material is. It is an analytical chemist's guide to the properties of the material and tells precisely how to prepare and test samples; also what test results are acceptable for it to be considered that high grade of purity. It is a how-to guide.
So chemists follow the monograph using good laboratory practices to properly prepare samples and equipment. The tests have been independently validated and replicated, so the results are based on standardized test methodology.
Some results could be chemical fingerprints based on analytical equipment such as HPLC, GC, FTIR, etc. Others may be based on chemical properties or molecular weight. So the results will vary by substance and method. Usually there will be a narrow range of acceptable results within the limits of expected experimental error but generally close to 100% purity (such as 98-101%).

Anonymous said...

Hi Neil,

Thanks for the excellent explanation. I've come across a product that I think is using the term "pharmaceutical grade" falsely. After talking to the manufacture, I'm actually more concerned than before because it seems like they're intentionally trying to mislead consumers. Is there an authority that handles issues like this? Whom do I report this to?

Neil E. Levin, CCN, DANLA said...

Let's not forget that, for a substance with only a foreign pharmacopeial monograph (British Pharmacopeiai-BP; Japanese Pharmacopeia-JP) and not one in the USP, one might be able to accurately label it as pharmaceutical grade but not as USP grade. However, the battery of tests descibed in whatever monograph is used must be done and all test results be within monograph specifications in order accurately to label something as "pharmaceutical grade". Some would accept monographs published by other authoritative scientific bodies, as well.

However, I suggest first asking the company for the basis of its claim. If you are still not satisfied, consider lodging a complaint with the company and seeing how it responds before escalating the dispute by complaining to a third party. That seems only fair and this due diligence may protect you, as well.

You could next try the Natural Products Association, if the company is a member of that trade association.

If you do end up convinced that it has mislabeled its product and get nowhere with the company or trade association, the appropriate bodies you could complain to include the BBB, FDA, or FTC, depending on how you want to go. That would be a drastic step, which you should consider carefully before pursuing.