1H NMR as an analytical tool for the investigation of hydrolysis rates: a method for the rapid evaluation of the shelf-life of aqueous solutions of drugs with ester groups.
The rate of hydrolysis of esters of primary and secondary alcohols can be determined quickly and easily by 1H NMR in aqueous solution, provided that the water signal is suppressed by the WATR (Water Attenuation by T2 Relaxation) method. To evaluate this approach, Arrhenius plots have been constructed for hydrolysis of acetylcholine, carbachol and atropine, and the effect of pH on the hydrolysis of procaine has been determined over a limited range. The results agree well with literature values for rate constants.
Department of Pharmacy, University of Manchester, UK.
A J
AJ
Ferdous
N A
NA
Dickinson
R D
RD
Waigh
D000109:Acetylcholine / Q000032:analysis; D001285:Atropine / Q000032:analysis; D002217:Carbachol / Q000032:analysis; D004355:Drug Stability; D004952:Esters / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D011343:Procaine / Q000032:analysis; D012996:Solutions / Q000032:analysis; D013696:Temperature
D004952:Esters; D012996:Solutions; D011343:Procaine; D001285:Atropine; D002217:Carbachol; D000109:Acetylcholine