title: The determination of RWJ-38705 (tramadol N-oxide) and its metabolites in preclinical pharmacokinetic studies using LC-MS/MS.
abstract: A rapid and reliable analytical method is described for the simultaneous determination of RWJ-38705 (tramadol N-oxide) and several of its major metabolites in the plasma of Sprague-Dawley rats and Beagle dogs. Sample preparation using solid phase extraction was followed by reversed phase liquid chromatography (LC) coupled with tandem mass spectrometric (MS/MS) detection in the positive ionization mode. The assay was linear for all analytes over concentrations ranging from approximately 6 to 2000 ng/ml. The inter-assay reproducibility was generally less than 15% while accuracy values were within 13% of theoretical. The overall recovery of the analytes ranged from approximately 40 to 64% in rat plasma and 53-75% in dog plasma. This assay has proven to be sensitive, specific and reproducible, and it has been readily implemented in preclinical PK studies. Representative plasma concentration versus time profiles resulting from administration of TNO to rats and dogs are presented in this communication.
authors.affiliation: Department of Bioanalytical Drug Metabolism, The R. W. Johnson Pharmaceutical Research Institute at Ortho Pharmaceutical Corporation, Raritan, NJ 08869, USA. sjuzwin@prius.jnj.com
authors.forename: S J
authors.initials: SJ
authors.lastname: Juzwin
authors.forename: D C
authors.initials: DC
authors.lastname: Wang
authors.forename: N J
authors.initials: NJ
authors.lastname: Anderson
authors.forename: F A
authors.initials: FA
authors.lastname: Wong
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000927:Anticonvulsants / Q000097:blood / Q000378:metabolism* / Q000493:pharmacokinetics; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid / Q000379:methods*; D004285:Dogs; D007275:Injections, Intravenous; D013058:Mass Spectrometry / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D014147:Tramadol / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism / Q000493:pharmacokinetics
chemical_list: D000927:Anticonvulsants; C101588:tramadol N-oxide; D014147:Tramadol