Survey of Low Field NMR Spectrometer Platforms for Successful Screening of Sexual Enhancement and Weight Loss Supplements for Adulteration with Drugs and Drug Analogs
John C Edwards1, Kristie M Adams2, and Anton Bzhelyansky2
1Process NMR Associates, Danbury, CT
2United States Pharmacopeial Convention, Rockville, MD
The adulteration of dietary supplements (or natural health products) with synthetic pharmaceuticals is an area of increasing concern, which presents substantial risk to public health. Widely available in retail and via the Internet, these products are often marketed as sexual enhancement, weight loss and/or bodybuilding supplements. Unlike prescription drugs, supplements do not require premarket approval by FDA before they are made available for public consumption. In fact, the agency can only take investigational action after the adulterated product has caused harm and the adverse event has been reported via MedWatch (FDA’s online portal for voluntary reporting of adverse events associated with drugs, medical devices and dietary supplements).
Development of analytical tools for screening and identification of adulterated products in the marketplace represents a significant step forward in the fight against adulterated dietary supplements. Several organizations, including AOAC and USP, have undertaken initiatives to evaluate and recommend analytical methodologies for screening supplements for adulteration. HPLC and mass spectrometry have so far dominated the screening and quantitation studies published in the literature, with NMR spectroscopy often relegated to the status of structure elucidation tool. In this work, we investigate the ability of several-low field NMR spectrometric platforms to successfully identify and quantify the presence of adulterating drug substances in sexual enhancement and weight loss supplements purchased online and in US retail. 1H qNMR of both types of samples was performed with 300 MHz NMR to confirm the presence of adulterants such as sildenafil, tadalafil, and their structural analogues (sexual enhancement supplements) and various synthetic stimulants (weight loss supplements). We have concluded that a simple sample preparation protocol combined with straightforward 1H NMR spectroscopic analysis yields a rapid, robust and reliable screening test for adulterated supplements, presenting an attractive alternative to more labor-intensive, expensive and expertise-demanding techniques du jour.
This was presented by John Edwards at SMASH in September 2014, and at the Carolina NMR Symposium in November 2014
presentation can found here: Benchtop NMR – Herbal Supplement Adulteration Screening