Iodometric determination of quinine sulfate in tablets using N-oxidation with diperoxysebacic acid

Using diperoxysebacic acid as an example, it was shown the interaction of diperoxycarboxylic acids with quinine alkaloid in an aqueous medium by kinetics method. The reaction proceeds quantitatively by the mechanism of nucleophilic substitution of β-peroxide oxygen atom in diperoxycarboxylic acid with the formation of the corresponding N-oxide, and the kinetics of the process is a subject to general rules of specific acid-base catalysis. New iodometric methods were developed, and the possibility of quinine sulfate quantification in pure form ‘Quinine sulfate’, as well as in the combined dosage form ‘Limpar® N 200 mg’ (Cassella Med GmbH, Germany) and in ‘Quinine sulfate 200 mg Tablets’ (Accord Healthcare Ltd, UK) by the reaction of oxidation with diperoxycarboxylic acid. They are characterized by high selectivity, and rate, simplicity of performing, and good accuracy. No toxic reagents or special conditions required. RSD ≤1.6% (δ =+0.40..+0.72%), LOQ=0.01 mg.