title: Solid-phase extraction and optimized separation of doxorubicin, epirubicin and their metabolites using reversed-phase high-performance liquid chromatography.
abstract: A reversed-phase isocratic high-performance liquid chromatographic method is described in which a formal structured procedure was applied to predict the mobile phase composition giving optimal baseline resolution of the clinically important anticancer agents doxorubicin and 4'-epidoxorubicin (epirubicin), their principal metabolites, and daunorubicin (internal standard). These formal statistical procedures included the simultaneous techniques of solvent selectivity triangle and factorial design for range-finding preliminary studies, followed by use of the modified simplex, a sequential procedure. These were used to select the parameters of organic modifier, buffer strength and pH necessary for use with a Spherisorb ODS 1 column, to achieve optimal separation of eight anthracycline solutes. Ultraviolet and fluorescence detection was used (lambda ex = 254 nm, lambda em = 560 nm), and the latter gave a low detection limit for doxorubicin in serum of 1 ng ml-1. The optimal mobile phase composition was determined to be acetonitrile-0.06 M Na2 HPO4 containing 0.05% (v/v) triethylamine adjusted to pH 4.6 with 0.03 M citric acid (35:65, v/v). A solid-phase extraction method was developed to enable the selective isolation of anthracyclines by adsorption onto C8 Bond-Elut cartridges, and is based on extraction of serum spiked with a mixture of the anthracycline solutes. The anthracyclines were eluted using acetonitrile-0.2 M Na2 HPO4 containing 0.05% (v/v) triethylamine adjusted to pH 3.6 with 0.1 M citric acid (67.5:32.5, v/v). Reproducible recoveries for doxorubicin (94 +/- 8%) and for epirubicin (96 +/- 8%) were obtained (n = 5). In particular, recoveries for the 7-deoxyaglycone metabolite (99%) were higher than other extraction methods cited.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Pharmaceutical Chemistry, School of Pharmacy, University of Bradford, West Yorkshire, UK.
authors.forename: G
authors.initials: G
authors.lastname: Nicholls
authors.forename: B J
authors.initials: BJ
authors.lastname: Clark
authors.forename: J E
authors.initials: JE
authors.lastname: Brown
mesh_terms: D000042:Absorption; D002851:Chromatography, High Pressure Liquid; D003630:Daunorubicin / Q000032:analysis / Q000302:isolation & purification; D004317:Doxorubicin / Q000032:analysis / Q000302:isolation & purification* / Q000378:metabolism; D015251:Epirubicin / Q000032:analysis / Q000302:isolation & purification* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008433:Mathematics; D012015:Reference Standards; D015203:Reproducibility of Results
chemical_list: D015251:Epirubicin; D004317:Doxorubicin; D003630:Daunorubicin