Category: Automation and High-Throughput Technologies

1391-B - A rapid, high-throughput assay for detecting PDE5 inhibitors in dietary supplements

Monday, February 5, 2018
5:00 PM - 6:00 PM

Products marketed as dietary supplements for sexual enhancement are frequently adulterated with phosphodiesterase-5 (PDE5) inhibitors, which are erectile dysfunction drugs or their analogs that can cause severe health effects. To combat widespread adulteration and protect public health, a rapid, high-throughput screening assay was developed to detect PDE5 inhibitors in sex enhancement products. The assay employs fluorescence detection and is based upon measuring inhibition of PDE5 activity, which is the pharmacological mechanism shared among the adulterants. After establishing and characterizing the assay reaction scheme, an analysis of dietary supplements serving as matrix blanks (n = 25) yielded no false positives. These samples were then spiked with nine individual PDE5 inhibitors, along with several mixtures. All nine adulterants were successfully detected (≤ 5 % false negatives; n = 20) at a concentration of 1.00 mg/g, which is over five times lower than concentrations commonly encountered in adulterated products. A major distinction of the PDE5 inhibition assay is the ability to detect adulterants without prior knowledge of their chemical structures, demonstrating a broad-based screening capability that can address a continuously evolving threat of new adulterants. The PDE5 inhibition assay can analyze over 40 samples simultaneously within 15 min, involves a single incubation step and simple data analysis, all of which are advantageous for combating the widespread adulteration of sex enhancement products.

Michael F. Santillo

Research Chemist
U.S. Food and Drug Administration (FDA)
Laurel, MD

Research Chemist