Quantitative ¹H NMR spectroscopic determination of the <i>E/Z</i> isomer ratio of the antidepressant drug fluvoxamine for use in pharmaceutical analysis

Abstract

Abstract High‐resolution NMR spectroscopy is a powerful tool in the elucidation of a structure with respect to constitution, configuration and conformation. In recent years, NMR has been increasingly used in quantitative analysis. In this study, we show the ability of 1 H NMR to determine the isomeric composition of the antidepressant drug fluvoxamine. The activity of fluvoxamine resides on the E ‐isomer, and the current British Pharmacopoeia limits the content of the Z ‐isomer to 0.5%. The NMR method described here is able to determine the content of the Z ‐isomer down to the 0.2% level on a total amount of 15 mg of the substance. Copyright © 2002 John Wiley &amp; Sons, Ltd.