The US Food and Drug Administration sent the letter on November 8, 2017, to a company called Vita-Pure Inc., which is based in Roselle, NJ. In addition to the mentions of problems with specifications, which is a common feature of warning letters sent to dietary supplement companies, the letter was unusual and significant in that it drilled down into the testing technology the company used to verify its products. And in particular how it was using that technology. FDA maintained that the company didn’t do enough background work to use its chosen test method effectively.
FTIR does not provide valid initial ID
“Specifically, you stated during the inspection that you rely on Fourier transform infrared spectroscopy (FTIR) for identity testing for dietary ingredients. While FTIR may be used to confirm that the supplier is consistent in sending the same product, FTIR does not ensure that the product received is what it is claimed to be. To verify the identity of a component that is a dietary ingredient, you must first authenticate that the ingredient is what it is stated to be, and then you may use that FTIR as a secondary authentication spectrum,” the warning letter stated.
James Neal-Kababick, founder of Flora Research Laboratories in Grants Pass, OR, said that the apparent simplicity of the FTIR method can lead companies astray. Indeed, an official from another company that recently received an FDA warning letter told NutraIngredients-USA that he had purchased an FTIR device and, judging from statements made during that interview, seemed to believe that just having the device on site and using it was going to be a cure-all for his ID testing woes.
“This is all about how people are the technology,” Neal-Kababick told NutraIngredients-USA. “FDA is right in saying that it does not by itself insure that products received are what they claim to be.”
Bias against FTIR
But Neal-Kababick said he was concerned that the way the letter was written could cast the technology into the shade, something he said might unfairly impugn its reputation. With the proper amount of background work, FTIR is a valuable and easy-to-use arrow in the testing quiver, provided you are aiming it at the right target.
“One problem is that there is a bias by FDA about this technique. Unfortunately that bias is because of rampant ignorance and abuse by people in the industry. They watch CSI and they have these handheld scanners and they think this is how it works. You point the scanner at the material at it tells you what it is. You can actually get there and use the instrument in that way, but it takes a lot of upfront R&D,” he said.
That R&D work consists of properly calibrating the instrument using validated standards, and then matching those results against what is typically coming from the supplier. This can help build up a chemometric model that Neal-Kababick said can be a scientifically defensible first line of ID verification. But he cautioned that this is a complicated technique that takes a level of skill and experience that might be beyond many companies.
With validation and SOP, it’s a powerful tool
“We use FTIR all the time to elucidate the structure of compounds we are working on. But I’m a spectroscopist with two and half decades of experience. If you are using it on a simple compound, like sodium ascorbate, it’s going to be pretty consistent. But if you are using it on curcumin, your ingredient might be a water-dispersible form, which is going to look different from an isopropyl extract,” he said.
In addition to the calibration of the company’s instrument using validated standards, Neal-Kababick said a standard operating procedure must be created as well. It’s definitely not a simple plug-and-play method. That SOP would include determining how materials might fail the test, as well as how they’re supposed to pass.
“I see this all the time that companies haven’t demonstrated how batches will fail. Or they will take the reading from their first sample and use that as the reference. There can be a circular reasoning, if they don’t have a validated standard to refer back to. This can be a powerful and elegant testing technique. Any technique can yield false data if it is improperly used,” he said.