Optoelectronic Method for Detection of Letrozole and its Metabolite in Urine Samples

摘要

The increase in the number of cases of breast cancer required the development of new pharmaceutical formulas, letrozole being one of the drugs used for this purpose. Treatment with this drug requires detection and monitoring of these substances. In the doping control of athletes, letrozole is a forbidden substance. Letrozole is included in the Prohibited List of World Anti-Doping Agency (WADA) at the Sections Hormone and Metabolic modulators, Aromatase inhibitors, selective estrogen receptor modulators (SERMs) and other anti-estrogenic substances. For the analysis of these compounds, the technique of choice is the liquid-chromatography tandem mass spectrometry technique (LC-MS/MS). Due to the metabolism of the substance, it is required the analysis of both the compound and the metabolite bis-(4- cyanophenyl)methanol by LC-MS/MS. In the WADA Technical Document TD2018MRPL, the Minimum Required Performance Levels for Detection and Identification of Non-threshold Substances (MRPL) for anti-estrogenic substances is 20 ng/mL. This paper discloses the optimization of the LC-MS/MS detection parameters of letrozol and letrozol metabolite.