A novel HPLC method for determination of EDTA in a cataract inhibiting ophthalmic drug

A novel HPLC method for determination of EDTA in a cataract inhibiting ophthalmic drug product has been developed. In this method EDTA was converted to Cu(II)EDTA complex, using Cu + 2 containing mobile phase, after injection into the chromatographic system. This allowed complexation of EDTA with Cu + 2 without interference from formulation ingredients. The Cu(II)EDTA complex was separated from drug substance, impurities, degradants and other formulation excipients by a 250 x 4.1 mm anion exchange column and detected at UV wavelength 250 nm. The mobile phase consisted of 2 mM cupric nitrate, 11 mM nitric acid, and 25% (v/v) acetonitrile at pH 3.0. This stability indicating assay has been validated and shown to be specific, linear, precise, accurate and rugged for routine EDTA analysis.