METHOD DEVELOPMENT AND VALIDATION OF LC-ESI-MS/MS TECHNIQUE FOR THE ESTIMATION OF MODAFINIL IN HUMAN PLASMA; APPLICATION TO PHARMACOKINETICS IN HEALTHY RABBITS

A new simple and sensitive liquid chromatography-electrospray ionization-tandem-mass spectrometric (LC-ESI-MS/MS) technique was developed and validated for the estimation of modafinil in human plasma and the method was applied to study pharmacokinetics in healthy rabbits. Chromatography was attained on Phenomenex- C₁₈ (50mm × 4mm) 5µ column and acetonitrile, methanol and 0.1% formic acid (25:60:15 v/v) mixture as the movable phase at 0.7 ml/min flowrate. Modafinil and modafinil-D5 internal standards were detected at m/z 274.2/229.0, m/z 279.1/234.0 respectively. Modafinil and modafinil-D5 (internal standard) were separated with liquid-liquid extraction. The technique was linear over the 2.0-600.0 ng/ml concentration range. This technique established with intrabatch and inter batch precision within 1.54-7.18% and 1.82-6.25%. This technique established with intrabatch and inter batch accuracy within 98.56-102.80% and 97.62-102.76 %.The drug was shown mean T_max of 3.833; average C_max, AUC0͢ t and AUC0͢ α_, for test formulation is 677.667; 6306 and 6471 respectively in the pharmacokinetic study on healthy rabbits.