Simple 1H NMR spectroscopic method for assay of salts of the contrast agent diatrizoate in commercial solutions
Hanna, G.M.; Lau-Cam, C.A.
Journal - Association of Official Analytical Chemists 79(4): 833-838
1996
ISSN/ISBN: 0004-5756 PMID: 8757438 Document Number: 459697
A simple, accurate, and specific 1H NMR spectroscopic method was developed for the assay of diatrizoate meglumine or the combination diatrizoate meglumine and diatrizoate sodium in commercial solutions for injection. A mixture of injectable solution and sodium acetate, the internal standard, was diluted with D-2O and the 1H NMR spectrum of the solution was obtained. Two approaches were used to calculate the drug content, based on the integral values for the -N-CO-CH-3 protons of diatrizoic acid at 2.23 ppm, the N-CH-3 protons of meglumine at 2.73 ppm, and the CH-3-CO-protons of sodium acetate at 1.9 ppm. Recoveries (mean +- standard deviation) of diatrizoic acid and meglumine from 10 synthetic mixtures of various amounts of these compounds with a fixed amount of internal standard were 100.3 +- 0.55% and 100.1 +- 0.98%, respectively. In addition to providing a direct means of simultaneously assaying diatrizoic acid and meglumine, the proposed NMR method can also be used to identify diatrizoate meglumine and each of its molecular components.