Spectrophotometric determination of procaine hydrochloride in pharmaceutical products using 1,2-naphthoquinone-4-sulfonic acid as the chromogenic reagent

Spectro photometric determination of procaine hydrochloride is described. The procaine hydrochloride reacts with 1,2-naphthoquinone-4-sulfonic acid in pH 3.60 buffer solution to form a salmon pink compound, and its maximum absorption wavelength is at 484 nm, epsilon(484) = 5.22 x 10(3) The absorbance for procaine hydrochloride from 0.30 to 100 Pg ml(-1) obeys Beer's law. The linear regression equation of the calibration graph is C = 19.23A - 0.03, with a linear regression correlative coefficient is 0.9996, the detection limit is 0.28 mug ml(-1); recovery is from 98.0 to 105.2%. Effects of pH, surfactant, organic solvent, foreign ions, and standing time on the determination of procaine hydrochloride have been examined. This method is rapid and simple, and can be used for the determination of procaine hydrochloride in injection solution of procaine hydrochloride. The results obtained by this method agreed with those by the official method (dead-stop titration). (C) 2003 Elsevier Science B.V. All rights reserved.