validating a stability indicating hplc method for kinetic study of cetirizine degradation in acidic and oxidative conditions

a stability indicating high-performance liquid chromatography (hplc) method wasvalidated and used to study the degradation of cetirizine dihydrochloride in acidic and oxidativeconditions. the separation was carried out on a symmetry c18 column and a mixture of 50 mmkh2po4 and acetonitrile (60:40 v/v, ph = 3.5) was used as the mobile phase. the method waslinear over the range of 1-20 μg/ml of cetirizine dihydrochloride (r2 > 0.999) and the withindayand between-day precision values were less than 1.5%. the results showed that cetirizinedihydrochloride was unstable in 2 m hcl and 0.5% h2o2. the kinetics of the acidic degradationshowed a pseudo-first-order reaction in the temperature range of 70-90°c. in addition, thekinetics of hydrogen peroxide mediated degradation was pseudo-first-order in the temperaturerange of 50-80°c.