SPECTROPHOTOMETRIC AND HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC DETERMINATION OF CETIRIZINE DIHYDROCHLORIDE IN PHARMACEUTICAL TABLETS

Derivative spectrophotometric, colorimetric and high performance liqui d chromatographic methods, for the determination of the antihistaminic cetirizine dihydrochloride in tablet form were described. Spectrophot ometrically, cetirizine was determined by the measurement of its first (D-1) and second (D-2) derivative amplitudes at 239 (peak) and 243-23 3 nm (peak-to-trough), respectively. The aqueous solutions obeyed Beer 's law in the concentration ranges of 1.2-10.0 and 0.8-10.0 mu g ml(-1 ) for D-1 and D-2 measurements, respectively. The colorimetric procedu re was based on measuring the absorbency of the coloured chromogen res ulted from the reaction between cetirizine sodium salt in polar solven t (DMF) and chloranil at 556 nm. The relation with concentrations was linear over 120-250 mu g ml(-1). Optimization of the reaction conditio ns was studied. At the same time, investigation of the complex formed was made with respect to its composition and the associated constant. A simple liquid chromatographic assay has been developed for the deter mination of cetirizine dihydrochloride in the presence of one of its s ynthesis precursor (hydroxyzine hydrochloride). A Bondapak-C-18 column was used with a mobile phase consisting of acetonitrile/0.01 M ammoni um dihydrogen phosphate (32:68, v/v) containing 0.1% w/v tetrabutyl am monium hydrogen sulphate adjusted to pH 3 with phosphoric acid at a fl ow rate of 2 ml min(-1). With salicylic acid as internal standard, qua ntitation was achieved with UV detection at 230 nm based on the peak h eight ratios. Beer's law was obeyed in a concentration range of 3-35 m u g ml(-1) and the regression line equation was derived with a correla tion coefficient of 0.9999. The validity of the methods was further co nfirmed using the standard addition method. The proposed procedures we re successfully applied to the determination of cetirizine in bulk and tablet form, with high percentage of recovery, good accuracy and prec ision. (C) 1998 Elsevier Science B.V. All rights reserved.