The adulteration of herbal dietary supplements with synthetic pharmaceuticals has
been recognized as a growing problem internationally, with the number of detected
cases rising every year. This has created a demand for high throughput analysis techniques.
In recent years novel ambient desorption ionisation techniques for surface analysis
of solid and liquid samples with subsequent MS detection have been reported [1,2,3].
Here we examine the utility of the Atmospheric Pressure Solids Analysis Probe (ASAP)
for the rapid determination of synthetic phosphodiesterase type-5 inhibitors (PDE5)
in counterfeit tablet samples and adulterated herbal supplements. Authentic brand
sildenafil citrate, vardenafil hydrochloride and tadalafil were obtained from reputable
pharmaceutical wholesalers. Imitation „brand“ samples of these drugs were obtained
from internet pharmacies. Five Herbal dietary supplements (HDS) available freely without
prescription were also purchased on-line. Samples were analyzed by ASAP with high
resolution MS. The instrument was operated in combined ESI/APCI mode. The principal
active component in 13 tablet samples was identified by ASAP in less than 20 minutes.
Sample extraction was not necessary and chromatographic separation was not required
to determine if the sample contained what it claimed to. Though the appearance of
the imitation tablets conformed to the appearance of the genuine medicine, results
from ASAP with Time-of-Flight (TOF) MS detection showed that the vardenafil and tadalafil
pills contained the wrong active pharmaceutical ingredient (API). All herbal supplements
purchased were found to be adulterated, containing either Sildenafil and/or Tadalafil
or analogues of these drugs, none of which was declared on the box or enclosed information.
References: [1] Takats Z, Wiseman JM, et al. (2004) Science, 306: 471. [2] Cody R, Laramee J,
et al. (2005) Anal Chem, 77: 2297. [3] McEwen CN, McKay RG, et al. (2005) Anal Chem,
77: 7826.
