Determinação de estimulantes, esteroides anabolizantes, diuréticos e laxante por HPLC-DAD e LC-MS/MS em suplementos alimentares adulterados disponíveis no Brasil

Abstract

The adulteration of dietary supplements by the addition of pharmacologically active substances is a serious issue, which is aggravating steadily. These substances are added intentionally in various products, with the aim of improving their effectiveness, but without proper labeling stating so. In addition to a public health problem, the consumption of supplements added with undeclared pharmacologically active substances also represents a career risk for professional athletes when it comes to doping in sport. In the present work, analytical methods based on liquid chromatography were developed for the detection of 19 pharmacologically active substances in dietary supplement samples at the levels of crosscontamination and adulteration. For this purpose, high performance liquid chromatography/diode array detector (HPLC-DAD) and liquid chromatography/tandem mass spectrometry (LC-MS/MS) were used. The investigated substances comprise of androgenic and anabolic effects (ie testosterone, testosterone propionate, testosterone decanoate, trenbolone, stanozolol, dehydroepiandrosterone, androstenedione, nandrolone decanoate, oxandrolone and metasterone), stimulant (ie caffeine), anorexigenic (ie sibutramine), diuretic (ie amiloride, bumetanide, furosemide, hydrochlorothiazide and chlorthalidone) and laxative (ie phenolphthalein). Among the sample preparation methods evaluated (Quechers and solidliquid extraction followed by a protein precipitation step), solid-liquid extraction using methanol as extraction solvent and ZnSO4 as the precipitating agent has been chosen as it has shown recovery values above 80% for all evaluated substances. The proposed analytical methods had limits of detection and quantification within the contamination range, they were also selective and linear showing r 2 values higher than 0.99 in the concentration range of interest for all substances and accuracy within acceptable values. A representative sampling of dietary supplements marketed in Brazil, consisting of 230 samples, was analyzed and more than 25% have shown to be positive for caffeine (48), sibutramine (14), phenolphthalein (2) and furosemide (3), isolated or associated with each other. The methods developed used a simple sample preparation and presented satisfactory results for the investigation of possible adulteration or cross-contamination for the 19 of the substances of interest. From a total of 58 adulterated dietary supplements, only 11 could be considered adulterated by crosscontamination. The remaining are considered to be intentional additions by manufacturers in order to improve the efficiency of their products. The results presented in this study indicate the need for more effective measures by the health authorities towards the production and marketing of these products so that the general public is aware of their potential adulteration and the risks associated with their consumption.