A sensitive, selective and first automated method is described for the quantification of Ibuprofen in human plasma using Diclofenac as internal standard. The Bioanalytical approach consists of Liquid -Liquid extraction with 70:30 extraction mixture, chromatographic separation of 10μL injected sample with nonpolar(C18) column using 45:45:10 isocratic solvent mixture as mobile phase followed by quantification with mass detector in selective reaction monitoring mode using electro spray ionization mode (ESI) as an interface. The method was fully validated over a concentration range of 0.01 to 40 μg/ml using 0.1 ml of human plasma per assay. Stability assessment was also included. The run time for assay is 1.5 min. Robotic liquid handling systems are employed to all liquid transfer steps including the sample preparation procedure as well as to the addition/removal of the organic solvent. The current method includes a simple and rapid sample preparation as a result of robotic systems utilization that enabled parallel processing as well as shorter analysis run time compared to previously published methods. The method was applied successfully to the analysis of plasma samples obtained for pharmacokinetic, bioavailability or bioequivalence studies after therapeutic doses of Ibuprofen.
