Pyridostigmine-d₃is intended for use as an internal standard for the quantification of pyridostigmine by GC- or LC-MS. Pyridostigmine is an inhibitor of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE; IC₅₀s = 0.35 and 1 μM, respectively, for the human enzymes).¹Pyridostigmine (10 µM) reduces decreases in AChE activity induced by the organophosphate pesticides diisopropyl fluorophosphate, chlorpyrifos-oxon, diazinon-oxon, paraoxon, and malaoxon in isolated bovine red blood cells.²It also reduces soman-induced membrane depolarization and decreases in AChE activity in isolated human muscle bundles in a concentration-dependent manner.³Pyridostigmine (3 mg/kg per day for four weeks) prevents tachycardia and increases in sympathetic tone in mice following myocardial infarction induced by left coronary artery ligation.⁴Formulations containing pyridostigmine have been used in the treatment of myasthenia gravis and as neuromuscular protective agents against organophosphate poisoning.

1.Strelnik, A.D., Petukhov, A.S., Zueva, I.V., et al.Novel potent pyridoxine-based inhibitors of AChE and BChE, structural analogs of pyridostigmine, with improved in vivo safety profileBioorg. Med. Chem. Lett.26(16)4092-4094(2016) 2.Henderson, J.D., Glucksman, G., Leong, B., et al.Pyridostigmine bromide protection against acetylcholinesterase inhibition by pesticidesJ. Biochem. Mol. Toxicol.26(1)31-34(2012) 3.Maselli, R.A., Henderson, J.D., Ng, J., et al.Protection of human muscle acetylcholinesterase from soman by pyridostigmine bromideMuscle Nerve43(4)591-595(2011) 4.Durand, M.T., Becari, C., de Oliveira, M., et al.Pyridostigmine restores cardiac autonomic balance after small myocardial infarction in micePLoS One9(8)e104476(2014)