Development and validation of a GC-MS method for the determination of hydroxyzine and its active metabolite, cetirizine, in whole blood.

A simple, rapid, sensitive and accurate gas chromatography-mass spectrometric method was developed and validated for the simultaneous determination of hydroxyzine and cetirizine in whole blood. Solid-phase extraction procedure using Bond Elut LRC Certify II columns was used for the isolation of hydroxyzine and cetirizine from 1mL whole blood followed by derivatization with a mixture of acetic anhydride:n-propanol (1:1, v/v). Limits of detection and quantification were 1.50 and 5.00ng/mL, respectively. The assay was linear within the concentration range of 5.00-1000.0ng/mL and the correlation coefficient was R