High Performance Liquid Chromatographic tandem mass spectrometric method for the estimation of Carbocisteine in human plasma has been developed and validated using Carbocisteine 13 C 3 as internal standard. Sample preparation process was accomplished by solid phase extraction technique. The processed sample was chromatographed and analyzed on Luna 5u HILIC 200 A (150 x 4.6 mm) column using mobile phase [Acetone-M: Buffer-1(40:60% v/v)] and diluent as [Acetone-M: Water (90:10% v/v)] .Carbocisteine was chromatographed and analyzed by MS Detector. The analytical method described is valid the determination of Carbocisteine (over a range of 52.27 μg/ml to 5301.83 μg/ml) using as Carbocisteine 13 C 3 internal standard in human plasma. Signal from the detector were captured in a computer and processed using MassLynx SCN 4.1 v software. This method was found suitable to analyze human plasma samples for the application in pharmacokinetic and BA/BE studies.
