Identification of Erectile Dysfunction Drugs in Dietary Supplements by Liquid Chromatography Ion Trap Mass Spectrometry

Abstract

With the rise in consumption of dietary supplements for various ailments such as erectile dysfunction (ED), there is concern that these supplements may contain illegally added phosphodiesterase type 5 (PDE-5) inhibitor and its analogs. HPLC or LC is a general separation method, and MS is a detection technique, together LC/MS/MS technology provides the mass spectral confirmation in identifying sildenafil, vardenafil, tadalafil and their analogs. In our present study, a sample extraction technique with 1:1 acetonitrile: water solvents and sonication was used for screening, then identification was performed using an LC coupled with Velos Pro linear ion trap mass spectrometry. This was a simple and reliable method for a variety of matrices of dietary supplements and pharmaceutical formulations in tablet, capsule or liquid form. The run time is only 6.5 min, allowing for a quick screening and identification of all of analytes of ED drugs using full scan and data-dependent scan MS/MS, except for tadalafil and aminotadalafil (MS/MS/MS). To conclude this study, Sildenafil, tadalafil, vardenafil, and other 16 analogs in dietary supplements could be quickly screened and identified by HPLC coupled with ion trap MS using data dependent scanning function. The main method using the short column is very rapid, and saves a lot of running time and solvents, and the identification is further confirmed by MS/MS information. The current study develops and validates a quick and reliable method to screen for ED drugs.

Keywords:

• Dietary supplements
• ED drugs adulteration
• LC/MS/MS
• PDE-5 inhibitors

Declaration of interest

The authors declare no conflicts of interest. The authors alone are responsible for the content and writing of the article.

Additional information

Notes on contributors

Charlie Li

Dr. Charlie Li obtained both MS and Ph.D. from Oregon State University in 1991 and 1994, respectively. He completed his first postdoctoral research with UC Davis (1994-1997), and a second postdoctoral research with ARS-USDA in Albany, CA (1997-1998). He then worked with food industry for three years. Dr. Li joined the State of California to work for Department of Toxic Substances Control, and OEHHA in 2001, and since 2008, with Food and Drug Laboratory Branch, California Department of Public Health.

Dadong Xu

Dr. Dadong Xu received his Ph.D. degree from the Chinese Academy of Sciences in 1995. He worked at University of California, Davis from 1997 to 2008 as staff scientist. Dr. Xu joined the State of California in 2008 working in different programs such as Drinking Water Program, Genetic Disease Screening, and Food and Drug Laboratory. He has published more than 40 papers in peer-reviewed Journals.

Bahman Moezzi

Dr. Bahman Moezzi had received his Ph.D. degree in chemistry from the University of California, Davis in 1987. Dr. Moezzi has 33 years of supervisory and technical experience in the area of analytical chemistry while working at private and state laboratories. He has been with the Food and Drug Laboratory Branch (FDLB) since 2001 and most recently served as the laboratory Manager/Chief. Previously, Dr. Moezzi had been the laboratory manager at three environmental and industrial hygiene testing laboratories in Southern California and had obtained laboratory accreditations from the American Association for Laboratory Accreditation (A2LA) and American Industrial Hygiene Association (AIHA) for his laboratories. He has extensive and in-depth knowledge of advanced analytical instrumentation and the official methodologies used for analysis of food, drug, environmental, and industrial hygiene samples. As the laboratory liaison, he had worked with many federal, state and local investigators in various projects that involved collection and analysis of several thousand samples per year and had always been able to successfully manage his team to analyze these samples with high levels of accuracy and on a timely manner. At FDLB, he has been involved in several public health investigations such as lead in candy, domoic acid in seafood, and mercury in skin-lightening creams.