title: Determination of MDL 201,012 at femtomole/millilitre levels in human plasma by liquid chromatography with electrochemical detection.
abstract: A sensitive and selective liquid chromatographic method to quantitate MDL 201,012 in human plasma was developed and validated. MDL 201,012 (I), diethyl-MDL 201,012 (internal standard, II) and desmethyldiol-MDL 201,012 (masking agent, III) were isolated from basified plasma (2 mL) by solid phase extraction using Bond-Elut C-18 cartridges. Endogenous components were selectively removed prior to eluting the analytes from the sorbent. Components were separated using on-line LC column switching with a cyanopropyl precolumn and a phenyl analytical column. The analytical column effluent was monitored electrochemically at a glassy carbon electrode at a potential of +1025 mV vs. Ag/AgCl. Peak-height ratios were proportional to the amount of MDL 201,012 added to plasma over the range 125-7500 pg/mL MDL 201,012. Absolute recovery of MDL 201,012 from human plasma was > 94% across the calibration range. The minimum quantitation limit was 125 pg/mL. Assay precision (%RSD) ranged from 5.2 to 13% based on the analysis of quality control standards containing 125, 250, 500, 1000, 2500, 5000 and 7500 pg/mL MDL 201,012. Corresponding assay accuracy (% relative error) was +/- 8.5%. The method has been successfully used to quantitate MDL 201,012 in samples from acute dose tolerance studies in human volunteers.
authors.affiliation: Clinical Pharmacology Department, Marion Merrell Dow, Inc., Kansas City, Missouri 64134.
authors.forename: D L
authors.initials: DL
authors.lastname: Reynolds
authors.forename: L S
authors.initials: LS
authors.lastname: Eichmeier
authors.forename: D H
authors.initials: DH
authors.lastname: Giesing
mesh_terms: D000480:Alkynes / Q000097:blood*; D000588:Amines; D002851:Chromatography, High Pressure Liquid; D003503:Cyclobutanes / Q000097:blood*; D004563:Electrochemistry; D004566:Electrodes; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D011786:Quality Control; D012997:Solvents; D013056:Spectrophotometry, Ultraviolet; D001750:Urinary Bladder, Neurogenic / Q000188:drug therapy
chemical_list: D000480:Alkynes; D000588:Amines; D003503:Cyclobutanes; D007202:Indicators and Reagents; D012997:Solvents; C071274:1-cyclobutyl-7-(dimethylamino)-1-hydroxy-1-phenyl-5-heptyn-2-one