H-1-NMR determination of the enantiomeric excess of the antiarrhythmic drug Mexiletine by using mandelic acid analogues as chiral solvating agents

Several optically active mandelic acid analogues were shown to allow a direct H-1-NMR determination of the enantiomeric composition of Mexiletine [1-(2,6-dimethylphenoxy)-2-propanamine], a chiral, orally effective antiarrhythmic agent, and some of its derivatives. Excellent results were obtained with few milligram samples, at room temperature in CDCl3, without the need of deconvolution software, and regardless of the instrument used (200 or 300 MHz).