Metoclopramide-d3 is intended for use as an internal standard for the quantification of metoclopramide by GC- or LC-MS. Metoclopramide is an orally bioavailable serotonin (5-HT) receptor 5-HT3 antagonist with Ki and IC50 values of 995 and 308 nM, respectively, in rat cortical membranes. It is also a dopamine D2 receptor antagonist (IC50 = 483 nM in rat brain synaptic membranes). Oral administration of metoclopramide inhibits emesis induced by cisplatin and apomorphine in ferrets and dogs with ED50 values of 6.17 and 0.45 mg/kg, respectively. Metoclopramide reversibly inhibits human acetylcholinesterase (AChE) isolated from the caudate nucleus (Kis = 9.3 and 82 μM for competitive and non-competitive inhibition, respectively). Formulations containing metoclopramide have been used as anti-emetic and antipsychotic agents.
