title: Determination of estramustine phosphate and its metabolites estromustine, estramustine, estrone and estradiol in human plasma by liquid chromatography with fluorescence detection and gas chromatography with nitrogen-phosphorus and mass spectrometric detection.
abstract: Bioanalytical methods for the determination of estramustine phosphate by liquid chromatography and its four main metabolites estromustine, estramustine, estrone and estradiol by gas chromatography are described. For the estramustine phosphate assay the plasma was purified by protein precipitation followed by a C18 solid-phase extraction. For the metabolite assay the plasma samples were purified by a C18 solid-phase and liquid-liquid extraction procedure and derivatised by silanization. Thereafter, estramustine and estromustine were quantified by gas chromatography with nitrogen-phosphorus detection and estradiol and estrone were quantified by gas chromatography with selected ion monitoring. The methods were validated with respect to linearity, selectivity, precision, accuracy, limit of quantitation, limit of detection, recovery and stability. The limit of quantitation was 2.3 micromol/l for estramustine phosphate, 30 nmol/l for estromustine and estramustine, 12 nmol/l for estrone and 8 nmol/l for estradiol. The results showed good precision and accuracy for estramustine phosphate and the four metabolites. The intermediate precision was 6.2-13.5% (C.V.) and the accuracy was 91.8-103.9%.
authors.affiliation: Active Biotech Research AB, Lund, Sweden. karin.edman@activebiotech.com
authors.forename: K
authors.initials: K
authors.lastname: Edman
authors.forename: L
authors.initials: L
authors.lastname: Svensson
authors.forename: B
authors.initials: B
authors.lastname: Eriksson
authors.forename: P O
authors.initials: PO
authors.lastname: Gunnarsson
mesh_terms: D018906:Antineoplastic Agents, Alkylating / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004961:Estramustine / Q000097:blood*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D009584:Nitrogen; D010758:Phosphorus; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence
chemical_list: D018906:Antineoplastic Agents, Alkylating; D010758:Phosphorus; D004961:Estramustine; D009584:Nitrogen