Spectral investigation and analytical application of the vinylamino-substituted haloquinone derivatives of Nizatidine and Ranitidine

Abstract

Studies were carried out, for the first time, to investigate the formation and spectral characteristics of N-vinylamino-substituted haloquinone derivatives of nizatidine and ranitidine. The reactions involved the condensation of N-alkylvinylamine formed from the interaction between the free secondary amino groups in the investigated drugs and acetaldehyde with each of chloranil, bromanil, and 2,3-dichloronaphthoquinone. The experimental conditions affecting the reactions were optimized and the characteristics of the absorption spectra of the formed colored derivatives were established. Under the optimum reaction conditions and at the λ_max of the formed derivatives, linear relationships were found between the absorbances and the concentrations of the investigated drugs in a concentration range of 10–250  mg ml^-1. The limits of assays detection were 2.61–7.77 mg ml^-1. The precisions of the methods were satisfactory; the relative standard deviations were 1.13–1.73%. The proposed methods were successfully applied to the analysis of the studied drugs in pure and pharmaceutical dosage forms with good accuracy; the recovery percentages were 98.1–101.8 ± 0.58–1.57%. The results were compared favorably with those of the official methods.