High-performance thin-layer chromatography for the determination of cetirizine in human plasma and its use in pharmacokinetic studies.

A rapid and sensitive high-performance thin-layer chromatography (HPTLC) assay has been developed for the measurement of cetirizine in human plasma and its utility for pharmacokinetic study has been evaluated. In the proposed HPTLC method, protein-bound cetirizine was freed by proteolysis of plasma proteins by incubating the plasma with 0.35% pepsin and then extracting with 2 mL pH 5.0 phosphate buffer, followed by 4 mL chilled chloroform. The chloroform layer was separated and concentrated. An aliquot of the extract was then spotted on precoated silica-gel 60 F254 plates using a Camag Linomat IV autosampler. Quantification was with the help of a dual-wavelength TLC scanner. The proposed method had a recovery of 98% and the lowest amount of cetirizine that could be detected was 50 ng. The method was applied for the determination of the plasma levels and pharmacokinetic parameters of cetirizine after oral administration of two marketed preparations in healthy volunteers and the pharmacokinetic parameters determined by the proposed method were in agreement with previously reported values.