Desenvolvimento de métodos eletroanalíticos para a determinação de tibolona e metabólitos em saliva e 1-(3-clorofenil)piperazina (mCPP) em amostras apreendidas

Abstract

Tibolone (TIB) is a synthetic steroid that is effective in preventing postmenopausal bone loss (osteoporosis) and climacteric symptoms. This drug has been included since 2006 in the group of anabolic agents in the annual list of substances considered doping by WADA. In this thesis we describe electrochemical methods for the determination of TIB and the metabolites 3α-hydroxytibolone (3α-OHTIB) and 3β-hydroxytibolone (3β-OHTIB) in real saliva samples using square wave voltammetry (SWV) and boron doped diamond (BDD) as the working electrode. Saliva samples were only diluted in supporting electrolyte (0.1 mol L-1 phosphate buffer, pH 7) and the mean recovery values were 104 ± 3% for TIB and 98 ± 5% for 3α-OHTIB and 3β-OHTIB. A limit of detection (LOD) of 0.3 μmol L-1 was obtained for the three compounds. The method was also applied to the quantification of TIB in pharmaceutical formulations and the results obtained were statistically similar to those obtained by HPLC (95% confidence interval). The metabolites, 3α-OHTIB and 3β-OHTIB, were also determined in synthetic urine using differential pulse voltammetry and BDD electrode as the working electrode. BR buffer 0.04 mol L-1 (pH = 3) was used as a supporting electrolyte and a linear response range of 1 to 35 μmol L-1 and a LOD of 0.1 μmol L-1 were found. The quantification of the metabolites was possible after simple dilution of samples (1: 1) in support electrolyte (mean recovery value of 101 ± 5%) with 1- (3-chlorophenyl) piperazine (mCPP) is part of the group of new psychoactive substances, with other effects, such as stimulant and hallucinogenic. Electrochemical method using SWV was developed for the detection of mCPP in seized samples using a screen-printed carbon electrode (SPCE). The detection of mCPP was performed by the drop-casting method and presented a linear response range from 1 to 30 μmol L-1 with LOD = 0.1 μmol L-1. The method proved to be efficient for the detection of mCPP in seized samples contained other electroactive compounds (methamphetamine or ecstasy.