Low picogram determination of Ro 48-6791 and its major metabolite, Ro 48-6792, in plasma with column-switching microbore high-performance liquid chromatography coupled to ion spray tandem mass spectrometry.
A coupled liquid chromatography/tandem mass spectrometry assay was developed for simultaneous determination of Ro 48-6791 and its secondary amine metabolite in human plasma samples with a quantification limit for both compounds of 1 pg/mL using a 1 mL plasma aliquot. The method exploits the enhanced mass sensitivity of a microbore (300 microns i.d.) reversed-phase capillary column coupled to an ion spray probe combined with tandem mass spectrometry. A straightforward column-switching system was utilized to focus the analytes onto a microbore trapping column following solid-phase extraction of a 50 microL plasma sample extract from liquid/liquid extraction. Backflushing of the retained analytes from the trapping column onto the microbore capillary column provided the requisite high peak concentration for high sensitivity. The inter-assay precision and accuracy for Ro 48-6791 and its metabolite, at 10 pg/mL, were found to be 3.4%, and 105%, and 9.1%, and 99.9%, respectively. The calibration curves were linear over the range 1 to 1000 pg/mL. The method proved to be sufficiently rugged for analysis of samples.
Zell
M
M
Department of Drug Metabolism & Pharmacokinetics, F. Hoffmann-La Roche Ltd, Basel, Switzerland.
Husser
C
C
Hopfgartner
G
G
D014151:Anti-Anxiety Agents; D001569:Benzodiazepines / Q000097:blood*; D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D015394:Molecular Structure; D015203:Reproducibility of Results
D014151:Anti-Anxiety Agents; C107068:Ro 48-6792; D001569:Benzodiazepines; C104519:Ro 48-6791