Validated selective spectrophotometric methods for the kinetic determination of desloratidine in tablets and in the presence of its parent drug

Two novel selective validated methods have been developed for analysis of desloratidine (DSL) in its tablets formulation. Both were kinetic spectrophotometric methods, depend on the interaction of the secondary amino group in DSL with acetaldehyde to give N-vinylpiperidyl product. The formed N-vinylpiperidyl compound was reacted with 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil) to form colored N-vinylpiperidyl-substituted benzoquinone derivatives. The formed blue-colored derivative was measured at 672 nm. The reaction conditions were carefully studied and all factors were optimized. The molar ratio between the reactants was estimated and a suggested reaction mechanism was presented. The analysis was carried out using initial rate and fixed time (at 6 min) methods. The linear concentration ranges were 3–50 and 10 – 60 μg mL−1 with limits of detection of 3.2 and 2.2 μg mL−1 for the initial rate and fixed time methods, respectively. ICH guidelines were applied for analytical performance validation of the proposed methods. The presence of common excipients in the pharmaceutical formulation did not produce any significant interference, as well as from loratadine, which is the parent compound of DSL. Different commercially available tablets formulations containing were successfully analyzed, with, the percentage recovery ranging from 97.28–100.90 ± 0.7 2–1.41%. The obtained results were compared statistically with the reported method results. The proposed methods have similar accuracy and precision as the reported as indicated from the F- and t-test data.