Pulsed amperometric detection (PAD) of diuretic drugs in herbal formulations using a gold electrode following ion-pair chromatographic separation

Adulterated dietary supplements commercialized in Brazil: development of a screening method and a preliminary study of cytotoxicity

The high consumption of dietary supplements was a fundamental driver for the creation of the regulatory framework by the Brazilian governmental authorities. However, the regulatory agencies lack official low-cost methodologies to evaluate the quality of food supplements. A preliminary screening method by HPLC-DAD was proposed and validated for screening and quantification of adulterants in dietary supplements. The limits of detection and quantification were <0.11 and 0.37 µg.g-1, respectively. The method was applied for the investigation of ten unauthorized substances (spironolactone, hydrochlorothiazide, furosemide, clenbuterol, testosterone, testosterone propionate, yohimbine, vardenafil, tadalafil, and sildenafil) with a time of analysis of <5 min. Sixteen percent of the 44 samples analyzed had at least one adulterant at or above therapeutic concentrations. Subsequently, in vitro evaluations were performed of the potential cytotoxicity to evaluate the cell viability, DNA damage, determination of nitric oxide levels, and quantification of reactive oxygen species. Despite the necessity of further studies, the results indicate a relationship between the presence of adulterants in food supplements and a potential cytotoxic effect.

Research on Detection of Sterol Doping in Sports by Electrochemical Sensors: A Review

The use of doping by athletes to improve performance is prohibited. Therefore, doping testing is an important step to ensure fairness in sports. Doping is gradually metabolized in the body and is therefore difficult to detect immediately by a common method. At the same time, the emergence of new doping agents poses a challenge for highly sensitive detection. Electrochemical sensors are a fast, highly sensitive, and inexpensive analytical detection technology. It provides qualitative and quantitative determination of analytes by altering the electrochemical signal of the analyte or probe at the electrode. In this min-review, we summarized the different electrochemical sensing strategies for sterol doping detection. Some of the representative papers were interpreted in detail. In addition, we compare different sensing strategies.

Lateral Flow Immunochromatography Assay for Detection of Furosemide in Slimming Health Foods

In recent years, furosemide has been found to be abused in slimming health foods. There is an urgent need for a simpler, faster method for detecting furosemide in slimming health foods. In this study, a rapid, convenient and sensitive lateral flow immunochromatography (LFIA) based on Au nanoparticles (AuNPs) was established for the first time. Under optimal conditions, the qualitative limit of detection (LOD) of the AuNPs-based LFIA was 1.0~1.2 μg/g in slimming health foods with different substrates. AuNPs-LFIA could specifically detect furosemide within 12 min (including sample pretreatment) and be read by the naked eye. The developed AuNPs-LFIA showed high consistency with liquid chromatography with tandem mass spectrometry (LC-MS/MS), and no false positive or false negative results were found in spiked slimming health foods, proving that the AuNPs-LFIA should be accurate and reliable. The AuNPs-LFIA reported here provides a serviceable analytical tool for the on-site detection and rapid initial screening of furosemide for the first time.

An Ultra-High Performance Liquid Chromatography-Electrospray Tandem Mass Spectrometric Method for Screening and Simultaneous Determination of Anorexic, Anxiolytic, Antidepressant, Diuretic, Laxative and Stimulant Drugs in Dietary Supplements Marketed for Weight Loss

The consumption of dietary supplements is increasing every year all over the world and has been accompanied by an increased frequency of adulteration of these products with synthetic pharmaceuticals. Analytical methods that allow testing for the presence of synthetic drugs in dietary supplements are needed to detect such fraudulent practices. To investigate the adulteration of dietary supplements marketed for weight loss using different commercial appeals, we developed an analytical method using ultra-high-performance liquid chromatography-electrospray tandem mass spectrometry (UHPLC-ESI-MS/MS) for simultaneous determination of 32 drugs, including anorexics, anxiolytics, antidepressants, diuretics, laxatives and stimulants. Separation was accomplished in 19 minutes using a Zorbax SB-C18 column and a gradient elution program with 0.05% formic acid in water/acetonitrile as a mobile phase. Limits of quantification ranged from 0.14 to 3.92 μg L-1, and accuracy ranged from 80.00 to 119.48%. A simple extraction procedure was used in the pretreatment step by dissolving the samples in 100% methanol followed by a 1000 to 10,000-fold dilution in the mobile phase and filtration through a Teflon membrane (0.2 μm). The method was applied to the screening and quantification of the drugs in 108 formulations marketed as food supplements for slimming, weight loss, thermogenics, and supplements for meal replacement. Caffeine and p-synephrine were found as stimulants in 80 samples, listed or not on the label.

A new approach to ion exchange chromatography with conductivity detection for adulterants investigation in dietary supplements

The extent of adulteration of dietary supplements has significantly increased in recent years. This situation worries health authorities and requires auxiliary analytical tools for the investigation of illegal substances purposely added. Ion exchange chromatography with conductivity detection is a consolidated analytical technique for the determination of inorganic compounds in various matrices. This technique has been applied to the pharmaceutical characterization of mainly impurities and degradation products. This work presents a new approach to ion exchange chromatography as a screening method to investigate the presence of amfepramone, femproporex, sibutramine, bisacodyl and amiloride in dietary supplements advertised for weight loss. The method was optimized and validated using a Metrosep C4 100/4.0 cation exchange column. The mobile phase consisted of 1.8 mm HNO₃ containing 2% acetonitrile (v/v), with a flow rate of 0.9 ml min^-1 , and nonsuppressed conductivity detection was applied. The limits of detection and quantification varied from 1.01 to 3.62 mg L^-1 and from 1.48 to 8.72 mg L^-1 , respectively. The proposed method was successful applied to 78 solid dietary supplement samples, in two of which adulterations were found. Moreover, ion exchange chromatography with conductivity detection could be easily used for quality control without prior complex sample pre-treatment.

Analytical methods for determination of benzodiazepines. A short review

Benzodiazepines (BDZs) are generally commonly used as anxiolytic and/or hypnotic drugs as a ligand of the GABAA-benzodiazepine receptor. Moreover, some of benzodiazepines are widely used as an anti-depressive and sedative drugs, and also as anti-epileptic drugs and in some cases can be useful as an adjunct treatment in refractory epilepsies or anti-alcoholic therapy. High-performance liquid chromatography (HPLC) methods, thin-layer chromatography (TLC) methods, gas chromatography (GC) methods, capillary electrophoresis (CE) methods and some of spectrophotometric and spectrofluorometric methods were developed and have been extensively applied to the analysis of number of benzodiazepine derivative drugs (BDZs) providing reliable and accurate results. The available chemical methods for the determination of BDZs in biological materials and pharmaceutical formulations are reviewed in this work.