RESUMEN
A stability indicating High-Performance Liquid Chromatography [HPLC] method was validated and used to study the degradation of cetirizine dihydrochloride in acidic and oxidative conditions. The separation was carried out on a Symmetry C18 column and a mixture of 50 mM KH[2]PO[4] and acetonitrile [60:40 v/v, pH = 3.5] was used as the mobile phase. The method was linear over the range of 1-20 micro g/mL of cetirizine dihydrochloride [r[2] > 0.999] and the within-day and between-day precision values were less than 1.5%. The results showed that cetirizine dihydrochloride was unstable in 2 M HCl and 0.5% H[2]O[2]. The kinetics of the acidic degradation showed a pseudo-first-order reaction in the temperature range of 70-90[degree sign]C. In addition, the kinetics of hydrogen peroxide mediated degradation was pseudo-first-order in the temperature range of 50-80[degree sign]C