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 lmax 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.