MDAN-21

MDAN-21 is a **bivalent opioid ligand** designed by chemically linking a mu-opioid receptor agonist pharmacophore (derived from oxymorphone) to a delta-opioid receptor antagonist pharmacophore (derived from naltrindole) with a 21-atom spacer. It acts as a potent analgesic in preclinical models, notably showing high mu-opioid agonist activity while its delta antagonist component is thought to reduce or abolish the development of tolerance and physical dependence. Animal studies (both in rodents and nonhuman primates) indicate that MDAN-21 produces analgesia, substitutes for morphine in morphine-dependent subjects, and relieves allodynia without inducing tolerance, physical dependence, or drug-seeking behaviors typically associated with opioids. Preclinical evidence suggests MDAN-21 may act preferentially on mu-delta opioid receptor heteromers, potentially through "bridging" both targets, which contributes to its unique pharmacological profile[2][3][5][6].