JWH-051 is an analgesic drug which is a cannabinoid agonist. Its chemical structure is closely related to that of the potent cannabinoid agonist HU-210, with the only difference being the removal of the hydroxyl group at position 1 of the aromatic ring. It was discovered and named after John W. Huffman.
AMG-3 (part of the AM cannabinoid series) is an analgesic drug which is a cannabinoid agonist. It is a derivative of Δ8THC substituted with a dithiolane group on the 3-position side chain. AMG-3 is a potent agonist at both CB1 and CB2 receptors with a Ki of 0.32nM at CB1 and 0.52nM at CB2, and its particularly high binding affinity has led to it being used as a template for further structural development of novel cannabinoid drugs. It has sedative and analgesic effects, with analgesia lasting for up to 36 hours after administration.
AMG-41 (part of the AM cannabinoid series) is an analgesic drug which is a cannabinoid agonist. It is a derivative of Δ8-THC substituted with a cyclopropyl group on the C1'-position of the C3-alkyl side chain. AMG-41 is a potent agonist at both CB1 and CB2, with a Ki of 0.44 nM at CB1 vs 0.86 nM at CB2.
Ibipinabant (SLV319, BMS-646,256) is a drug used in scientific research which acts as a potent and highly selective CB1 antagonist. It has potent anorectic effects in animals, and was researched for the treatment of obesity, although CB1 antagonists as a class have now fallen out of favour as potential anorectics following the problems seen with rimonabant, and so ibipinabant is now only used for laboratory research, especially structure-activity relationship studies into novel CB1 antagonists. SLV330, which is a structural analogue of Ibipinabant, was reported active in animal models related to the regulation of memory, cognition, as well as in addictive behavior. An atom-efficient synthesis of ibipinabant has been reported.
SER-601 (COR-167) is a drug which acts as a potent and selective cannabinoid CB2 receptor agonist, based on a quinolone-3-carboxylic acid core structure, with 190 times selectivity for CB2 over the related CB1 receptor. It has analgesic effects in animal studies, as well as neuroprotective effects, but without a "cannabis high" due to its low affinity for CB1. A number of related compounds are known, almost all of which have high selectivity for CB2.
AM-630 (6-Iodopravadoline) is a drug that acts as a potent and selective inverse agonist for the cannabinoid receptor CB2, with a Ki of 32.1 nM at CB2 and 165x selectivity over CB1, at which it acted as a weak partial agonist. It is used in the study of CB2 mediated responses and has been used to investigate the possible role of CB2 receptors in the brain. AM-630 is significant as one of the first indole derived cannabinoid ligands substituted on the 6-position of the indole ring, a position that has subsequently been found to be important in determining affinity and efficacy at both the CB1 and CB2 receptors, and has led to the development of many related derivatives.
Org 28312 is a drug developed by Organon International which acts as a potent cannabinoid receptor full agonist at both the CB1 and CB2 receptors. It was developed with the aim of finding a water-soluble cannabinoid agonist suitable for intravenous use as an analgesic, but did not proceed to human trials, with the related compound Org 28611 chosen instead due to its better penetration into the brain. The structure-activity relationships of these compounds have subsequently been investigated further leading to the development of a number of more potent analogues, derived by cyclisation around the indole or piperazine rings.
JWH-302 (1-pentyl-3-(3-methoxyphenylacetyl)indole) is an analgesic chemical from the phenylacetylindole family, which acts as a cannabinoid agonist with moderate affinity at both the CB1 and CB2 receptors. It is a positional isomer of the more common drug JWH-250, though it is slightly less potent with a Ki of 17 nM at CB1, compared to 11 nM for JWH-250. Because of their identical molecular weight and similar fragmentation patterns, JWH-302 and JWH-250 can be very difficult to distinguish by GC-MS testing.
AZ-11713908 is a drug developed by AstraZeneca which is a peripherally selective cannabinoid agonist, acting as a potent agonist at the CB1 receptor and a partial agonist at CB2. It has poor blood–brain barrier penetration, and so while it is an effective analgesic in animal tests, it produces only peripheral effects at low doses, with much weaker symptoms of central effects compared to other cannabinoid drugs such as WIN 55,212-2. Many related benzimidazole-derived cannabinoid ligands are known.
MN-25 (UR-12) is a drug invented by Bristol-Myers Squibb, that acts as a reasonably selective agonist of peripheral cannabinoid receptors. It has moderate affinity for CB2 receptors with a Ki of 11 nM, but 22x lower affinity for the psychoactive CB1 receptors with a Ki of 245 nM. The indole 2-methyl derivative has the ratio of affinities reversed however, with a Ki of 8 nM at CB1 and 29 nM at CB2, which contrasts with the usual trend of 2-methyl derivatives having increased selectivity for CB2 (cf. JWH-018 vs JWH-007, JWH-081 vs JWH-098).
O-1269 is a drug that is a diarylpyrazole derivative, related to potent cannabinoid antagonist drugs such as rimonabant and surinabant. However O-1269 and several related drugs were unexpectedly found to act as full or partial agonists at the cannabinoid receptors rather than antagonists, and so produce the usual effects expected of cannabinoid agonists in animal tests, such as sedation and analgesic effects. The N-heptyl homolog O-1270 and the N-propyl homolog O-1399 also act as cannabinoid agonists with similar potency in vivo, despite weaker binding affinity at cannabinoid receptors compared to the pentyl homolog O-1269. Agonist-like and atypical cannabinoid activity has also been observed with a number of related compounds.
LBP-1 is a drug originally developed by Organon for the treatment of neuropathic pain, It acts as a potent and selective cannabinoid receptor agonist, with high potency at both the CB1 and CB2 receptors, but low penetration of the blood–brain barrier. This makes LBP-1 peripherally selective, and while it was effective in animal models of neuropathic pain and allodynia, it did not produce cannabinoid-appropriate responding suggestive of central effects, at any dose tested.
S-444,823 is a drug developed by Shionogi which is a cannabinoid agonist. It was developed as an antipruritic, and has moderate selectivity for the CB2 subtype, having a CB2 affinity of 18nM, and 32x selectivity over the CB1 receptor. In animal studies it showed analgesic effects and strongly reduced itching responses, but without producing side effects such as sedation and catalepsy that are seen with centrally acting CB1 agonists.
BIM-018 is a synthetic cannabinoid that is the benzimidazole analog of JWH-018. It is presumed to be a potent agonist of the CB2 receptor and has been sold online as a designer drug.
QMPSB is an arylsulfonamide-based synthetic cannabinoid that has been sold as a designer drug.
MCHB-1 is a benzimidazole derived drug which was researched as an analgesic but never developed for medical use. It acts as a potent agonist of the CB2 receptor, with an EC50 of 0.52nM at CB2, and ~30x selectivity over CB1 (Ki of 110nM at CB1 vs 3.7nM at CB2). It has been sold online as a designer drug, first being identified in Germany in December 2013.
Cannabinor (PRS-211,375) is a drug which acts as a potent and selective cannabinoid CB2 receptor agonist. It is classed as a "nonclassical" cannabinoid with a chemical structure similar to that of cannabidiol. It has a CB2 affinity of 17.4nM vs 5585nM at CB1, giving it over 300x selectivity for CB2. It showed analgesic effects in animal studies especially in models of neuropathic pain, but failed in Phase IIb human clinical trials due to lack of efficacy.
RQ-00202730 is a benzimidazole derived drug that acts as a potent and highly selective agonist for the CB2 cannabinoid receptor, with a Ki value of 19nM at CB2 and more than 4000x selectivity over CB1, though it also shows some activity as an antagonist of the unrelated 5-HT2B serotonin receptor. It has analgesic and antiinflammatory effects in animal studies, and was developed for the treatment of irritable bowel syndrome, but was ultimately discontinued from development following disappointing results in Phase II clinical trials.
