Simple and rapid spectrophotometric assay of levocetirizine in pharmaceuticals through charge-transfer complexation using chloranilic acid and 2,3-dichloro-5,6-dicyanoquinone as π-acceptors

Simple, rapid, selective and fairly sensitive method is described for the determination of levocetirizine (LCTZ) in pure form and in its dosage forms. The method is based on the formation of intensely colored charge-transfer (CT) complexes between LCTZ as donor with two π acceptors, chloranilic acid (CAA) and 2,3-dichloro-5,6-dicyanoquinone (DDQ) in acetonitrile-dioxane medium. The colored products were measured at 520 nm (CAA) and 590 nm (DDQ). Optimization of experimentation conditions is described. Beer’s law is obeyed over the concentration ranges 3-120 and 2-80 μg mL-1 for CAA and DDQ reagents, respectively, with corresponding molar absorptivity values of 4.0×103 and 5.5×103 L mol cm-1. The limits of quantification (LOQ) are 2.99 and 1.69 μg mL-1 for above reagents, respectively. Other method validation parameters, such as accuracy, precision, robustness and ruggedness, and selectivity are also reported. The composition of CT complex was found to be 1:1. The proposed method was successfully applied to the determination of the active ingredient in commercial tablets; and the results were in good agreement with those obtained by the official method. KEY WORDS: Levocetirizine, Spectrophotometry, Charge-transfer complex, Pharmaceuticals Bull. Chem. Soc. Ethiop. 2012, 26(3), 319-328. DOI: http://dx.doi.org/10.4314/bcse.v26i3.1