Nuclear Magnetic Resonance Simultaneous Analysis of Propantheline Bromide Structurally Related Impurities
G.M. Hanna, NRL, ORA, FDA, Brooklyn, NY 11232
A rapid, specific, and precise 1H-NMR spectroscopic method is described for the simultaneous analysis of propantheline bromide structurally related impurities, xanthene-9-carboxylic acid, xanthen-9-one, and 9-hydroxyxanthene. The impurities were calculated on the bases of relative intensities of corresponding signals at levels (mole/mole) of about 0.1%. NMR spectroscopy is potentially an exceptional technique for detection of impurities because it is sensitive to subtle changes in molecular structure, there can be equal sensitivity for all compounds (per nuclei), and there is no need for reference standards.