Bioanalytical LC-MS Method for the Quantification of Plasma Androgens and Androgen Glucuronides in Breast Cancer

The physiological and pathological development of the breast is strongly affected by the hormonal milieu consisting of steroid hormones. Mass spectrometry (MS) technologies of high sensitivity and specificity enable the quantification of androgens and consequently the characterization of the hormonal status. The aim of this study is the assessment of plasma androgens and androgen glucuronides, in the par excellence hormone-sensitive tissue of the breast, through the application of liquid chromatography-mass spectrometry (LC-MS). A simple and efficient fit-for-purpose method for the simultaneous identification and quantification of dehydroepiandrosterone sulfate (DHEAS), androstenedione (A4), androsterone glucuronide (ADTG) and androstane-3α, 17β-diol-17-glucuronide (3α-diol-17G) in human plasma was developed and validated. The presented method permits omission of derivatization, requires a single solid-phase extraction procedure and the chromatographic separation can be achieved on a single C18 analytical column, for all four analytes. The validated method was successfully applied for the analysis of 191 human plasma samples from postmenopausal women with benign breast disease (BBD), lobular neoplasia (LN), ductal carcinoma in situ and invasive ductal carcinoma (IDC). DHEAS plasma levels exhibited significant differences between LN, IDC and BBD patients (P < 0.05). Additionally, ADTG levels were significantly higher in patients with LN compared with those with BBD (P < 0.05)

Standard addition HPLC method for the determination of a-tocopherol in plasma samples of adolescent swimmers

Vitamin E (a-tocopherol, a-Toc) has been widely used as a powerful antioxidant that protects against oxidation of cellular components. It is used to treat muscular dystrophies, menstrual cycle disorders, risks of pregnancy interruption and abnormalities of gonadal function in men. It is also used frequently from athletes as nutritional supplement for performance enhancing. A simple HPLC method has been validated for the determination of a-Toc in human plasma, using a Nova-Pack analytical column. The chromatographic run time was less than 12 minutes using a mobile phase of Acetonitrile-Methanol 85:15 (v/v), at 0.999 mL/min flow rate while UV/Vis detector was adjusted at 292 nm. The purpose of this study was to evaluate two different approaches for the construction of the calibration curve and further quantify samples from swimmer athletes in order to investigate potential quantification differences. It was shown that the existence of a-Toc as endogenous compounds might affect the actual concentrations and should be considered as an essential parameter during the development of a bioanalytical method for the determination of a-tocopherol in human plasma

Standard addition HPLC method for the determination of a-tocopherol in plasma samples of adolescent swimmers

Vitamin E (a-tocopherol, a-Toc) has been widely used as a powerful antioxidant that protects against oxidation of cellular components. It is used to treat muscular dystrophies, menstrual cycle disorders, risks of pregnancy interruption and abnormalities of gonadal function in men. It is also used frequently from athletes as nutritional supplement for performance enhancing. A simple HPLC method has been validated for the determination of a-Toc in human plasma, using a Nova-Pack analytical column. The chromatographic run time was less than 12 minutes using a mobile phase of Acetonitrile-Methanol 85:15 (v/v), at 0.999 mL/min flow rate while UV/Vis detector was adjusted at 292 nm. The purpose of this study was to evaluate two different approaches for the construction of the calibration curve and further quantify samples from swimmer athletes in order to investigate potential quantification differences. It was shown that the existence of a-Toc as endogenous compounds might affect the actual concentrations and should be considered as an essential parameter during the development of a bioanalytical method for the determination of a-tocopherol in human plasma