Browsing by Subject "stanozolol"

The aim of this work was to investigate the feasibility of titanium dioxide (TiO2) photocatalysis for imitation of phase I metabolism of selected anabolic steroids. The role of the solvent composition and the time of UV exposure in the TiO2 photocatalysis were also investigated. TiO2 photocatalysis has been reported to produce mainly the same phase I reaction types formed in drug metabolism in vitro and in vivo. The selected anabolic steroids were testosterone, methyltestosterone, metandienone, nandrolone and stanozolol. Products from TiO2 photocatalysis were compared to products formed in microsomal incubations (HLM). Comparison was made on the basis of same mass, retention time and similarity of the product ion spectra. The samples were analyzed with ultra performance liquid chromatography (UPLC) and quadrupole time-of-flight mass spectrometry (Q-TOF). Electrospray ionization (ESI) in positive ion mode was used for ionization and product ion scan with two different collision energy was used for collision induced dissociation of the steroids and the reaction products. TiO2 photocatalysis is a simple and fast method. For all the steroids studied, the main reactions observed both in TiO2 photocatalysis and microsomal incubations were dehydrogenation, hydroxylation and combination of these two. Several isomers with same mass and retention time were formed. In addition, dihydroxylation and dihydroxylation+dehydrogenation products of stanozolol were observed both in TiO2 photocatalysis, but these were different isomers in different systems. In most cases the product ion spectra of isomers with same retention time were similar but the weak intensity of some peaks caused uncertainty in the interpretation of spectra. TiO2 photocatalysis might be useful in fast screening of possible drug metabolites. However the feasibility of TiO2 photocatalysis needs to be further studied because the differences in stereochemistry in TiO2 photocatalysis and microsomal incubations. If TiO2 photocatalytic reactions can be scaled up, it might be possible to produce standard compounds for example for doping laboratories.