Chiral separation of cetirizine, a second-generation H-1-antagonist, was studied by CD-mediated CE. Several parameters, including pH, CD type, buffer concentration, type of co-ion, applied voltage and temperature, were investigated. The best conditions for chiral separation were obtained using a 75 mM triethanolamine-phosphate buffer (PH 2.5) containing 0.4 mg/mL heptakis(2,3-diacetyl-6-sulfato)-beta-CD and 10% ACN. Online UV detection was performed at 214 nm, a voltage of 20 kV was applied and the capillary was temperature controlled at 25 degrees C by liquid cooling. Hydrodynamic injection was performed for 1 s. The method was validated for the quantification of levocetirizine in tablets and for enantiomeric purity testing of the drug substance. Selectivity, linearity, LOD and LOQ, precision and accuracy Were evaluated for both methods. The amount of levocetirizine dilhydrochloride in the commercially available tablets was quantified and was found to be within the specification limits of the claimed amount (5 mg). The amount of distomer in levocetirizine drug substance was found to be 0.87 +/- 0.09% w/w, which is in agreement with the certificate of analysis supplied by the company.