Pharmacokinetics and metabolism of formestane in breast cancer patients

Metabolism and excretion of anabolic steroids in doping control—New steroids and new insights

“…Among the major identified metabolites are 4-hydroxy-testosterone, 3,17-dihydroxyandrostan-4-ones; 3␣,4␤-dihydroxy-5␣-androstane-17-one, 3␤,4␤-dihydroxy-5␣-androstane-17-one, 4␤-hydroxy-5␣-androstan-3,17-dione and 3␣-hydroxy-5␤-androstan-4,17-dione (Fig. 7) [86][87][88][89]. Formestane itself was also identified as a metabolite of androst-4-ene-3,17-dione [40].…”

Applying in vitro NMR spectroscopy and H NMR metabonomics to breast cancer characterization and detection

“…In addition, 31 P NMR has been used in the analysis of metabolism as well. Glycolysis and phospholipid metabolism have been examined in great detail by using NMR perfusion studies which allow for the introduction of 13 C or 31 P labeled precursors, providing the necessary enrichment in metabolites for identification and characterization.…”

“…For the most part, NMR metabonomics has been applied to urine analysis to develop metabolic profiles that help investigators to understand drug toxicity and excretion. For breast cancer studies, this usually involves the monitoring of urinary levels of metabolic end products of anti-tumor compounds such as letrozole, indomethacin and formestane [29][30][31]. However, a search of the literature has resulted in no applications where urine Fig.…”

Detection of formestane abuse by mass spectrometric techniques

“…It is a type I aromatase inhibitor acting as a ‘suicide substrate’. In women it suppresses the formation of estrogen and then can be used therapeutically in those pathologies that are estrogen dependent (i.e., breast cancer) . In humans, estrogens are strong pituitary inhibitors of gonadotropin‐releasing factors.…”