title: A selective HPLC/RIA for dexamethasone and its prodrug dexamethasone-21-sulphobenzoate sodium in biological fluids.
abstract: A combined high performance liquid chromatography/radioimmunoassay procedure is described for the simultaneous determination of dexamethasone (DEX) and its prodrug dexamethasone-21-sulphobenzoate sodium (DSS) in plasma. After precipitation of the plasma proteins by acetonitrile, the protein-free supernatant was injected onto a C18 reversed phase liquid chromatographic system and DSS- and DEX-containing fractions were collected. Hydrolysis of DSS by 0.01 N NaOH, followed by fractions extraction of both hydrolysed DSS and DEX fractions with ethyl acetate allowed the use of a dexamethasone-specific radioimmunoassay for the selective determination of both compounds. The method is accurate and reproducible (intraday variability for DSS and DEX < 6%, interday variability for DEX 14%), allowing quantification of DEX and DSS as low as 0.3 ng/mL and 0.7 ng/mL, respectively.
authors.affiliation: College of Pharmacy, University of Florida, Gainesville 32610.
authors.forename: G
authors.initials: G
authors.lastname: Hochhaus
authors.forename: R
authors.initials: R
authors.lastname: Hochhaus
authors.forename: G
authors.initials: G
authors.lastname: Werber
authors.forename: H
authors.initials: H
authors.lastname: Derendorf
authors.forename: H
authors.initials: H
authors.lastname: Möllmann
mesh_terms: D002851:Chromatography, High Pressure Liquid; D003907:Dexamethasone / Q000031:analogs & derivatives* / Q000097:blood*; D006801:Humans; D006868:Hydrolysis; D011355:Prodrugs / Q000032:analysis*; D011863:Radioimmunoassay; D013056:Spectrophotometry, Ultraviolet
chemical_list: D011355:Prodrugs; C079704:dexamethasone-21-sulfobenzoate; D003907:Dexamethasone