title: Determination of N-methyl-4-isoleucine-cyclosporin (NIM811) in human whole blood by high performance liquid chromatography-tandem mass spectrometry.
abstract: A liquid chromatographic method with tandem mass spectrometric detection (LC-MS/MS) for the determination of N-methyl-4-isoleucine-cyclosporin (NIM811) was developed and validated over the concentration range 1-2500 ng/mL in human whole blood using a 0.05 mL sample volume. NIM811 and the internal standard, d(12)-cyclosporin A (d(12)-CsA), were extracted from blood using MTBE via liquid-liquid extraction. After evaporation of the organic solvent and reconstitution, a 10 microL aliquot of the resulting extract was injected onto the LC-MS/MS system. Chromatographic separation of NIM811 and internal standard was performed using a Waters Symmetry RP-8 (50 x 4.6 mm, 3 microm particle size) column. The mobile phase consists of 10 mm ammonium acetate in water (A) and acetonitrile (B), with 45% B from 0 to 0.2 min, 45 to 85% B from 0.2 to 0.8 min and 85% B from 0.8 to 2.2 min. The total run time was 3.5 min with a flow rate of 0.8 mL/min. The method was validated for sensitivity, linearity, reproducibility, stability, dilution integrity and recovery. The precision and accuracy of quality control samples at low (2.00 ng/mL), medium (20.0 and 400 ng/mL) and high (2000 ng/mL) concentrations were in the range 1.1-4.3% relative standard deviation (RSD) and -2.5-10.0% (bias), respectively, from three validation runs. The method has been used to measure the exposure of NIM811 in human subjects.
authors.affiliation: Department of Drug Metabolism and Pharmacokinetics, Novartis Pharmaceuticals Corporation, East Hanover, NJ 07936, USA. wenkui.li@novartis.com
authors.forename: Wenkui
authors.initials: W
authors.lastname: Li
authors.forename: Suyi
authors.initials: S
authors.lastname: Luo
authors.forename: Michael
authors.initials: M
authors.lastname: Hayes
authors.forename: Handan
authors.initials: H
authors.lastname: He
authors.forename: Francis L S
authors.initials: FL
authors.lastname: Tse
mesh_terms: D019540:Area Under Curve; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D016572:Cyclosporine / Q000008:administration & dosage / Q000097:blood*; D004355:Drug Stability; D006801:Humans; D007202:Indicators and Reagents; D016014:Linear Models; D015394:Molecular Structure; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D007202:Indicators and Reagents; D016572:Cyclosporine; C090438:(melle-4)cyclosporin