Spectrophotometric determination of nikethamide by charge--transfer complexation with chloranilic acid.

A Spectrophotometric method is described for assay of nikethamide which was based on charge transfer complexation between it and chloranilic acid. They form a complex with stoichiometric ratio of 1:1 and showed l-max at 535 nm. Maximum complexation occurred 30 min after mixing the reactants and was stable for 12 hr. The molar absorptivity, association constant and free energy for the complex were 1.05 x 1.0(2), 4.40 x 10(-2) litre mole-1 and 1819.02 kcal respectively. Conformity to Beer's Law was within the concentration range of 1-2.5 x 10(-4), which enabled the assay of dosage forms of the drug at microquantities.