Titrimetric micro determination of hydroxyzine using Oxone

Abstract

Abstract The kinetics of the oxidation reaction of hydroxyzine hydrochloride with potassium hydrogen peroxomonosulfate was studied depending on the pH of the medium. It was established for the first time that the kinetics of the reaction of N-oxidation of hydroxyzine obeyed the general laws of the mechanism of specific acid-base catalysis, proceeded quantitatively and stoichiometrically according to the mechanism of nucleophilic substitution of the β-oxygen atom of the peroxyacid group of peroxomonosulfate ions. It was shown that quantitative oxidation was achieved in 1–1.5 minutes at pH 8.0–8.5. The only reaction product was hydroxyzine N-oxide. A scheme of the oxidation process was proposed. Techniques were developed and the possibility of quantitative determination of hydroxyzine hydrochloride in the substance and tablets of 25 mg by iodometry using Oxone as an analytical reagent was shown. A known excess of reagent was added, and after a predetermined time, the residual reagent was determined iodometrically. RSD ≤ 1.52%. (x̅ - µ)· 100 / µ < RSD. The procedures had several advantages such as speed, simplicity, accuracy, selectivity, and cost-effectiveness, and therefore could be easily adapted by quality control laboratories for routine analysis.