A simple and sensitive extractive spectrophotometric method has been described for the assay of cetirizine dihydrochloride in pure and different pharmaceutical preparations. The method was based on the formation of the ion-pair complex from the reaction between cetirizine dihydrochloride and methyl orange in pH 4.0, which gave a yellow color after chloroform extraction and exhibited a maximum absorbance at 424.5 nm. Beer's law was obeyed in the concentration range of 2.5 - 20 μg/mL. The method was tested and validated for various parameters according to ICH guidelines. The detection and quantification limits were 1.0 and
3.0 μg/mL, respectively. The proposed method was successfully applied for the determination of cetirizine dihydrochloride in pharmaceutical
preparations. The results demonstrated that the procedure was accurate, precise and reproducible while statistical analysis of the obtained results showed no significant difference between the proposed method and reference method. No interference was observed for common pharmaceutical preparations.