Naloxegol-d5 is intended for use as an internal standard for the quantification of naloxegol (Item No. 23731) by GC- or LC-MS. Naloxegol is a peripherally acting antagonist of the μ-opioid receptor (Ki = 7.42 nM; pA2 = 7.95).1 It is selective for the μ-opioid receptor over the δ-opioid receptor (Ki = 866 nM). Naloxegol also acts as a partial agonist of κ-opioid receptors in vitro (EC50 = 47 nM for [35S]GTPγS binding) but lacks activity ex vivo at concentrations up to 10 μM. In vivo, naloxegol reverses morphine-induced decreases in gastrointestinal motility and analgesia in a hot-plate assay in rats (ED50s = 23.1 and 55.4 mg/kg, respectively), demonstrating a two-fold separation for peripheral versus CNS effects. Naloxegol also exhibits a brain uptake rate comparable to atenolol, a low-permeation standard with no brain uptake, in a rat brain perfusion model.WARNING This product is not for human or veterinary use.
