A comprehensive stability-indicating HPLC method for determination of chloroquine in active pharmaceutical ingredient and tablets: Identification of oxidation impurities
Malaria is the most common parasitic disease in humans. It is estimated that 3 billion people live under the risk of contracting this disease in the world. Chloroquine (CQ) is the drug of choice to treat cases of non-complicated malaria. Forced degradation studies are important to know the drug’s potentials degradation products and to develop a stability indicating method. Thus, chloroquine active pharmaceutical ingredient (API), chloroquine tablets and placebo were submitted to a detailed forced degradation study, using several stressing agents. The results were used on the development of a stability indicating method, using high performance liquid chromatography. The method was validated showing selectivity, precision, accuracy, robustness and linearity in the range of 30–360 μg/mL of chloroquine. Chloroquine API and tablets were susceptible to alkaline hydrolysis with NaOH 1 mol/L, and to oxidation with H2O2 3.0%. Two degradation products were formed in oxidative test. Kinetics of chloroquine degradation in alkaline hydrolysis was performed for both API and tablets. The calculated decay constant (k1) was 0.223 days−1 for API and 0.182 days−1 for tablets, while the half-life (t1/2) was 3.1 days for API and 3.8 days for tablets. Chemical structures have been proposed for the two degradation products formed in the presence of H2O2, using an UHPLC-UV-MS/MS approach.