RP-LC method for the determination of cetirizine in serum

The development and evaluation of HPLC method for quantifying cetirizine in human serum is described. The method involves liquid phase extraction of c etirizine in methylene chloride, adding diazepam as an internal standard, f ollowed by separation on a reversed phase C-18 Novapak column (150 x 3.9 nn ; 4 mu m), and employing a UV-detection set at 230 nm at ambient temperatur e. The mobile phase consists of a 13 mM phosphoric acid solution and aceton itrile (61:39 v/v) adjusted to pH 2.8 with 5 M NaOH. The assay is linear fr om 10 to 500 ng ml(-1) with a detection limit of 5 ng ml(-1) and a mean rec overy of 96.5%. The applicability of this method in pharmacokinetic studies is evaluated. (C) 2000 Elsevier Science B.V. All rights reserved.