(-)-Hyoscyamine-d3 is intended for use as an internal standard for the quantification of (-)-hyoscyamine by GC- or LC-MS. (-)-Hyoscyamine is a tropane alkaloid, a muscarinic receptor antagonist, and an isomer of atropine .1,2 (-)-Hyoscyamine inhibits the arterial depressor response induced by the muscarinic agonist methacholine in dogs.1 It is more effective than atropine at inhibiting EEG arousal in dogs following sciatic nerve stimulation when administered at doses of 0.5 and 1 mg/kg. (-)-Hyoscyamine induces convulsions in and is toxic to mice (LD50 = 95 mg/kg).2
1.Domino, E.F., and Hudson, R.D.Observations on the pharmacological actions of the isomers of atropineJ. Pharmacol. Exp. Ther.127(4)305-312(1959) 2.Authority, E.F.S.Scientific Opinion on Tropane alkaloids in food and feed EFSA Panel on contaminants in the food chain (CONTAM)EFSA J.11(10)3386(2013)