APPLICATION OF THE WATR TECHNIQUE FOR WATER SUPPRESSION IN H-1-NMR SPECTROSCOPY IN DETERMINATION OF THE KINETICS OF HYDROLYSIS OF NEOSTIGMINE BROMIDE IN AQUEOUS-SOLUTION
Aj. Ferdous et Rd. Waigh, APPLICATION OF THE WATR TECHNIQUE FOR WATER SUPPRESSION IN H-1-NMR SPECTROSCOPY IN DETERMINATION OF THE KINETICS OF HYDROLYSIS OF NEOSTIGMINE BROMIDE IN AQUEOUS-SOLUTION, Journal of Pharmacy and Pharmacology, 45(6), 1993, pp. 559-562
Both ammonium chloride and guanidinium chloride were used to secure wa
ter suppression in H-1 NMR spectra using the 'Water Attenuation by T2
Relaxation' (WATR) technique. The effect of phosphate buffer in the su
ppression was investigated over a range of pH values at 80 MHz. The sp
in-spin relaxation time of water protons at 80 MHz was found to reach
a minimum at pH 7.3 in the presence of 0.1 M phosphate buffer and 1 m
guanidinium chloride; these conditions were therefore chosen for subse
quent use of the WATR technique in a study of the kinetics of hydrolys
is of neostigmine bromide. The method was found to be very convenient
for studies of the hydrolysis of this representative amide.