title: Determination of the dihydrocodeine metabolites, dihydromorphine and nordihydrocodeine, in hepatic microsomal incubations by high-performance liquid chromatography.
abstract: A high-performance liquid chromatographic assay for the oxidative metabolites of dihydrocodeine, nordihydrocodeine and dihydromorphine, formed in human liver microsomal incubations, is described. A simple solvent extraction followed by reversed-phase high-performance liquid chromatography with UV detection allows quantification of both metabolites in a single assay. Standard curve concentration ranges for dihydromorphine and nordihydrocodeine were 0.05-5 and 0.2-20 microM, respectively. Assay performance was assessed by intra- and inter-day accuracy and precision of quality control (QC) samples. The difference between the calculated and the actual concentration and the relative standard deviation were less than 15% at low QC concentrations and less than 10% at medium and high QC concentrations for both analytes. The method provides good precision, accuracy and sensitivity for use in kinetic studies of the oxidative metabolism of dihydrocodeine in human liver microsomes.
authors.affiliation: Centre for Pharmaceutical Research, School of Pharmacy and Medical Sciences, University of South Australia, North Terrace, Adelaide, Australia.
authors.forename: L C
authors.initials: LC
authors.lastname: Kirkwood
authors.forename: R L
authors.initials: RL
authors.lastname: Nation
authors.forename: A A
authors.initials: AA
authors.lastname: Somogyi
mesh_terms: D000701:Analgesics, Opioid / Q000493:pharmacokinetics*; D000818:Animals; D000996:Antitussive Agents / Q000493:pharmacokinetics*; D002851:Chromatography, High Pressure Liquid; D003061:Codeine / Q000031:analogs & derivatives* / Q000032:analysis / Q000493:pharmacokinetics; D019389:Cytochrome P-450 CYP2D6 / Q000378:metabolism; D004090:Dihydromorphine / Q000032:analysis*; D006801:Humans; D066298:In Vitro Techniques; D008862:Microsomes, Liver / Q000201:enzymology / Q000378:metabolism*; D010084:Oxidation-Reduction; D051381:Rats; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000701:Analgesics, Opioid; D000996:Antitussive Agents; C109998:nordihydrocodeine; D004090:Dihydromorphine; D019389:Cytochrome P-450 CYP2D6; C014481:dihydrocodeine; D003061:Codeine