Abstract
An UPLC-MS method was developed and validated for determination of cyclosporine A (CsA) in whole blood samples. Hemolysed and protein precipitated blood samples were centrifuged and the supernatant was transferred for analysis. Mobile phase comprising of methanol (A) and 3mM ammonium acetate buffer (0.1% formic acid) (B) was used in gradient mode at a flow rate of 350 mu l/min. CsA and Cyclosporine D (CsD) were eluted on Acquity UPLC (R) BEH C18 1.7 mu m, 2.1x50mm Column. Retention time for CsA and CsD was 1.73 and 1.84 min, respectively. TQD-MS was operated under positive electrospray ionization mode (ESI+). The adducts of CsA (m/z 1225.1) and CsD (m/z 1239.1) were measured in single ion recording (SIR) mode. TQD-MS parameters were: cone voltage 92, capillary voltage 3.6 (kV), source temperature 150 degrees C, desolvation temperature 350 degrees C, desolvation gas 600 L/h, low mass resolution 15, high mass resolution 14 and ion energy 1.0. The method was simple, precise (%CV < 9.0), and accurate over the linearity range of 250ng/ml-5 mu g/ml. Lower limit of quantification for CsA was 250ng/ml. Extraction recovery of CsA at lower and higher quality control samples was about 35 - 40%. The method was successfully employed for pharmacokinetics studies of CsA.