RK-851 is a highly selective and orally active δ-opioid receptor antagonist, with a negative logarithm of the antagonist concentration (pA2) of 8.84. TRK-851 exhibits the selectivity for the δ receptor of more than 100 times higher than that for the μ or κ receptors. TRK-851 exhibits a potent antitussive effect in a rat model of capsaicin-induced cough. TRK-851 can be used for research on antitussive effects.

CJ-15161 is a κ-opioid receptor agonist. CJ-15161 can be used to study physiological functions such as pain relief and emotional regulation.

MP1202 is a dual-functional agonist of MOR and KOR with EC50s of 0.32 and 0.13  μM for mMOR-1 and mKOR-1, respectively. MP1202 has functional selectivity with reduction of β-arrestin1/2 recruitment but significant activation of G-protein and Gα-subtype at hMOR and hKOR. MP1202 has potent antinociceptive effects without typical opioid side effects, but it shows conditioned place preference and aversion behaviors in subtype-selective opioid KO mice model, promising for analgesia research.

MDAN-21 is a bivalent opioid ligand that contains both μ-opioid receptor agonists and δ-opioid receptor antagonists. MDAN-21 has a strong analgesic effect and does not produce tolerance in mouse studies. MDAN-21 can effectively inhibit the withdrawal of morphine dependent monkeys and alleviate abnormal pain in the study of rhesus monkeys. MDAN-21 can be used for the study of allodynia.

BRL-52656 is a blood-brain barrier (BBB)-penetrable KOR receptor agonist that exhibits a biphasic effect. At low doses, BRL-52656 decreases blood pressure, whereas high doses have the opposite effect in spontaneously hypertensive rats. Additionally, BRL-52656 induces water diuresis by inhibiting the secretion of vasopressin (AVP).

BU08028 is a dual-functional agonist that targets both the μ-opioid peptide receptor (MOP) and the neuropeptide FQ receptor (NOP). BU08028 activates the inhibitory G protein (Giα), thereby inhibiting the activity of adenylate cyclase (AC), resulting in a decrease in intracellular second messenger cyclic adenosine monophosphate (cAMP) levels, and suppressing the generation and transmission of pain signals. BU08028 can take effect within 30 minutes in mouse models of neuropathic pain and inflammatory pain, and its analgesic effect can last for up to 24 hours. BU08028 has excellent safety, no addiction, respiratory depression, or side effects. BU08028 can be used for pain research.

1-Naphthyl U-47700 is an α-isomer. 1-Naphthyl U-47700 is a racemic mixtures of the trans-isomers [R,R and S,S]. 1-Naphthyl U-47700 activates MOR in a concentration-dependent manner (EC50 > 23 μM).

SRI-22136 is a Delta Opioid Receptor (DOR) antagonist that can cross blood-brain barrier with a IC50 of 0.42 nM. SRI-22136 does not have agonistic activity but antagonistic activity against DOR, MOR (IC50 = 370 nM), KOR (IC50 = 54 nM) and can avoid addiction/aversion effects. SRI-22136 can effectively inhibit the BACE1 activity induced by DADLE (a DOR agonist)) (IC50 = 120 nM). SRI-22136 prevents completely Alzheimer’s-like pathology in mouse model. SRI-22136 can used for the study of Alzheimer’s disease.

AZD-2327 is a potent and selective δ-opioid receptor agonist. AZD-2327 binds to the human opioid receptor (Ki = 0.49 and 0.75 nM and EC50 = 24 and 9.2 nM at the C27 and F27 isoforms, respectively). AZD-2327 shows selectivity of >1000-fold over the human μ- and κ-opioid receptor subtypes as well as >130 other receptors and channels. AZD-2327 exhibits antidepressant and anxiolytic activities and can be used for the research of neurological disease.

Phenethyl 4-ANPP is a MOR (μ-opioid receptor) agonist. Phenethyl 4-ANPP is an analytical reference standard that is structurally similar to known opioids.

Sunobinop (S 117957) is a modulator of the opioid receptor-like orphan receptor (ORL1).

β-Funaltrexamine (β-FNA) hydrochloride is a selective μ opioid receptor antagonist. β-Funaltrexamine hydrochloride also inhibits cytokine-induced iNOS activation. β-Funaltrexamine hydrochloride inhibits neuroinflammation and ameliorated neuronal degeneration. β-Funaltrexamine hydrochloride has anti-inflammatory and neuroprotective effects and can be used for research of neurodegenerative diseases (eg: stroke)[1][2]

U-49900 is a utopioid.

U-48520 is an agonist for μ-opioid receptor with EC50 of 1561 nM.

Samidorphan isoquinoline dioxolane (Compound 16) is a cyclazocine analogue with opioid receptor binding properties.

Salvinorin A (Divinorin A) propionate is a potent, unique and short-acting high efficacy kappa-opioid receptor (KOPr) agonist with Ki value of 4.3 nm. Salvinorin A propionate is a non-nitrogenous neoclerodane isolated from Salvia divinorum.

Salvinorin A carbamate is an agonist for κ-opioid receptor with an EC50 of 6.2 nM and a Ki of 3.2 nM.

R-6890 is an opiate compound with analgesic potencies.

Orphine is an opioid compound. Orphine can enhance the antinociceptive effects in mice that are mitigated by Naloxone and a linker

N-Phenethylnoroxymorphone is an opioid compound. N-Phenethylnoroxymorphone enhances morphine-induced analgesia in rats. N-Phenethylnoroxymorphone can be used for research on neurological diseases.

Norcarfentanil hydrochloride is an opioid and is a metabolite of Carfentanil.

Nor-6α-Oxycodol is structurally similar to known opioids and is a metabolite of Oxycodone.

Naltrindole 5′-isothiocyanate (5'-NTII) is a non-selective delta opioid receptor antagonist that can antagonize the analgesic effects induced by DSLET without affecting the analgesic effects induced by DPDPE.

Methylketobemidone is structurally similar to known opioids.

Meta-fluoro 4-ANBP (m-Fluoro 4-ANBP) is structurally similar to known opioids.

LPK-26 hydrochloride is a selective kappa-opioid receptor agonist with a Ki of 0.68 nM. LPK-26 exhibits potent antinociceptive effects with low physical dependence potential and can be utilized in relevant research.

Homprenorphine is an opioid alkaloid derivative, structurally related to Cyprenorphine.

Fluorphine is an analogue of Brorphine and can bind to μ-opioid receptor (MOR) (Ki: 12.5 nM). Fluorphine has GTPγS binding (EC50: 75 nM) and βarrestin 2 recruitment (EC50: 377 nM) activity. Fluorphine induces respiratory depressant effects.

FEKAP is a brain-penetrant and selective kappa opioid receptor (KOR) agonist (Ki = 0.43 nM) which isotope labeled form exhibits excellent imaging properties. 11C-FEKAP can be utilized as a radiotracer for imaging KOR.

Dipyanone hydrochloride is structurally similar to known opioids.