title: An analytical method for cyclosporine using liquid chromatography-mass spectrometry.
abstract: A liquid chromatographic mass spectrometric (LC-MS) assay has been developed for cyclosporine A (CyA) in rat plasma using amiodarone as internal standard (IS). Rat plasma (100 microL) containing drug and IS were extracted using liquid-liquid extraction with 4 mL of 95:5 ether:methanol. After evaporation of the organic layer the residue was reconstituted with 500 microL of water. Then the aqueous layer was transferred to LC-MS sample vials. A 10 microL volume was injected. The analysis was performed on a C(8) column 3.5 microm (2.1 x 50 mm) heated to 60 degrees C with a mobile phase consisting of acetonitrile:methanol:0.2% NH(4)OH (60:20:20) at an isocratic flow-rate of 0.2 mL/min. The ions used for quantitation of CyA and IS were m/z 1202.8 and 645.9, with retention times of 3.35 and 4.72 min, respectively. Linear relationships (r(2) > 0.99) were achieved between plasma or blood concentration and peak height ratios (drug:IS) over the concentration range 50-5000 ng/mL. The CV% and mean error were <19%. Based on validation data, the lower limit of quantification for the assay was 50 ng/mL. The reported assay method displayed high measures of linearity, sensitivity, reliability and precision, allowing its applicability in pharmacokinetic studies in rat.
authors: Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada.
authors: Srividya V
authors: SV
authors: Kanduru
authors: Vishwa
authors: V
authors: Somayaji
authors: Afsaneh
authors: A
authors: Lavasanifar
authors: Dion R
authors: DR
authors: Brocks
mesh_terms: D000638:Amiodarone / Q000097:blood; D000818:Animals; D019540:Area Under Curve; D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D016572:Cyclosporine / Q000097:blood* / Q000493:pharmacokinetics; D006207:Half-Life; D007166:Immunosuppressive Agents / Q000097:blood* / Q000493:pharmacokinetics; D007202:Indicators and Reagents; D008297:Male; D013058:Mass Spectrometry; D010949:Plasma / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D012015:Reference Standards; D015203:Reproducibility of Results
chemical_list: D007166:Immunosuppressive Agents; D007202:Indicators and Reagents; D016572:Cyclosporine; D000638:Amiodarone