Determination of ipratropium bromide in vials using kinetic and first-derivative spectrophotometric methods.

Two sensitive and accurate spectrophotometric methods are presented for the determination of ipratropium bromide (IPB). The first method, kinetic method, is based on the alkaline oxidation of IPB with KMnO4. At a fixed time of 20 min, the formed manganate ion is measured at 608 nm. The concentration of IPB is calculated using the regression equation for the fixed-time method, at 20 min. The determination of IPB by fixed-concentration and rate-constant methods is feasible with regression equations obtained, but the fixed-time method was found to be more applicable. The second method uses first-derivative (D1-) spectrophotometry for the determination of IPB at 254-268 nm. The applicability of the proposed methods was examined by analyzing Atrovent unit dose vials and the percentage recoveries were 100.01+/-1.16, 100.02+/-0.97, for kinetic and D1- methods, respectively.