Simultaneous separation and determination of 20 potential adulterant antigout and antiosteoporosis pharmaceutical compounds in herbal food products using LC with electrospray ionization MS/MS and LC with quadrupole-time-of-flight MS.

An analytical method for the simultaneous and reliable determination of 20 antigout and antiosteoporosis pharmaceutical compounds in adulterated health food products was developed using liquid chromatography with electrospray ionization tandem mass spectrometry and liquid chromatography with quadrupole-time-of-flight mass spectrometry. The method was validated through the determination of specificity, linearity, limit of detection, and limit of quantification, method detection limit, method quantitation limit, precision, accuracy, recovery, and stability. The matrix effect was also determined. The validation results of the developed method are as follows: for solid and liquid blank samples, limits of detection ranged from 0.05 to 5.00 ng/mL and limits of quantification ranged from 0.15 to 15.00 ng/mL. Linearity was acceptable, and the correlation coefficients (R2 ) were ≥0.99 for all target compounds. Both intra and interday precision were less than 9.16% RSD, and accuracies ranged from 95.31 to 116.68%. Mean recoveries for different types of dietary supplements classified as powders, liquids, tablets, and capsules were found to be 80.81 to 117.62% with less than 15.00% relative standard deviation. The stability of the standard mixture solution was less than 11.72% relative standard deviation after 48 h. By the proposed method, the presence of dexamethasone was determined in seized herbal food products at concentrations that ranged from 126 to 215 µg/g.

Simultaneous determination of illegal drug substances in dietary supplements for gout and osteoporosis using ultra-performance liquid chromatography and liquid chromatography-quadrupole-time-of-flight mass spectrometry.

The aim of this study was to simultaneously determine the presence of unauthorized drug substances in health foods and herbal products used in the treatment of conditions such as gout and anti-osteoporosis. Therefore, we developed and optimised a rapid and accurate method to simultaneously measure 20 anti-gout and anti-osteoporosis drug substances using an ultra-high-performance liquid chromatography (UPLC) system equipped with a photodiode array (PDA) detector. The method was validated to fully meet internationally accepted standards. LODs and LOQs spiked in solid and liquid negative samples were ranged from 0.12 to 1.50 µg/mL, and ranged from 0.36 to 4.50 µg/mL. Linearities (R2> 0.999), stabilities (RSD ≤ 2.92%), accuracies (84.25∼106.62%, intra-day; 84.56∼105.85%, inter-day), precisions (RSD ≤ 3.71% on the intra-day; RSD ≤ 3.47% on the inter-day), recoveries spiked in various type of blank samples such as powder, liquid, tablet, and capsule were determined within 81.20-116.20 %, respectively. From a confirmation of matrix effects (88.06∼110.50% in solid blank; 89.16∼110.52% in liquid blank), it was confirmed that this method was not significantly affected by a sample matrix. The validated method was used to analyse 116 samples containing health foods, herbal products, and seized forensic samples advertised to be effective anti-gout and anti-osteoporosis agents. Of the 20 drug substances screened, dexamethasone was detected and confirmed by comparing the tandem mass spectrometry (MS/MS) fragment ion patterns of a reference standard and the sample using LC-quadrupole-time-of-flight (Q-TOF)/MS. The concentrations of adulterants in seized forensic samples ranged from 0.013 to 0.022 %.

Development of a specific fragment pattern-based quadrupole-Orbitrap mass spectrometry method to screen adulterated products of phosphodiesterase-5 inhibitors and their analogues.

Recently, adulterated supplements with phosphodiesterase-5 inhibitors (PDE-5i) have frequently observed. New synthetic analogues obtained from the chemical modification of parent compounds are frequently found in illicit products despite continuous efforts to inspect for these adulterants. A rapid and accurate method based on quadrupole-Orbitrap mass spectrometry was developed for simultaneously confirming and quantifying 85 PDE-5i and derived analogues present in illicit products for erectile dysfunction (ED). Common ions of PDE-5i according to their similar structures were proposed based on MS/MS fragmentations. These common ions could be an important diagnosis of their presence targets or new emerging analogues in supplements. Several validation parameters were employed, resulting in a limit of detection and quantification of 0.09-8.55 ng/mL and 0.24-17.10 ng/mL, respectively. The linear correlation coefficient (r2) was higher than 0.995, and mean recoveries of target compounds were in the range of 82-118%. A total of 187 illicit products, obtained from on/offline markets over a period of 3 years (2015-2017), were screened by the established method. Approximately 53% of them were adulterated with PDE-5i or derived analogues at concentrations of 0.1-726.0 mg/g in the illicit products. In the interests of public health, this study describes a rapid and accurate method to determine PDE-5i and new emerging analogues in adulterated products.

Isolation and characterisation of a novel sildenafil analogue adulterant, desmethylpiperazinyl propoxysildenafil, in a dietary supplement.

A new sildenafil analogue was detected during routine screening of dietary supplements suspected to be adulterated with an erectile dysfunction drug(s) using HPLC-DAD. The UV spectrum of this compound was highly similar to that of sildenafil and almost identical to that of desmethylpiperazinyl sildenafil. The analogue was purified by using semi-preparative HPLC and structurally elucidated by performing mass spectrometric and NMR spectroscopic experiments. The spectral data revealed that this sildenafil analogue bears an n-propoxy group instead of an ethoxy group and possesses no methylpiperazinyl moiety. The isolated compound, structure of which was further confirmed by spectral comparison with synthetic one, was thus named as desmethylpiperazinyl propoxysildenafil.

Determination of illegal adulteration of dietary supplements with synthetic hair-growth compounds by UPLC and LC-Q-TOF/MS.

In this study, we developed a UPLC-PDA and LC-Q-TOF/MS method to identify and measure the following prohibited substances that may be found in dietary supplements:triaminodil, minoxidil, bimatoprost, alimemazine, diphenylcyclopropenone, α-tradiol, finasteride, methyltestosterone, spironolatone, flutamide, cyproterone, dutasteride, and testosterone 17-propionate.The method was validated according to International Conference on Harmonization guidelines in terms of specificity, linearity, accuracy, precision, LOD, LOQ, recovery, and stability. The method was completely validated showing satisfactory data for all method validation parameters. The linearity was good (R2 > 0.999) with intra- and inter-day precision values of 0.2-3.4% and 0.3-2.9%, respectively. Moreover, the intra- and inter-day accuracies were 87-102% and 86-103%, respectively, and the precision was better than 9.4% (relative standard deviation).Hence, the proposed method is precise and has high quality,and can be utilised to comprehensively and continually monitor illegal drug adulteration in various forms of dietary supplements. Furthermore, to evaluate the applicability of the proposed method, we analysed 13 hair-growth compounds in 78 samples including food and dietary supplements. Minoxidil and triaminodil were detected in capsules at concentrations of 4.69 mg/g and 6.54 mg/g. In addition, finasteride was detected in a tablet at 13.45 mg/g. In addition, the major characteristic fragment ions were confirmed once again using LC-Q-TOF/MS for higher accuracy.