PB-22 (QUPIC or 1-pentyl-1H-indole-3-carboxylic acid 8-quinolinyl ester) is a designer drug offered by online vendors as a cannabimimetic agent, and detected being sold in synthetic cannabis products in Japan in 2013. The structure of PB-22 appears to use an understanding of structure-activity relationships within the indole class of cannabimimetics,[original research?] although its design origins are unclear. PB-22 represents a structurally unique synthetic cannabinoid chemotype, since it contains an ester linker at the indole 3-position, rather than the precedented ketone of JWH-018 and its analogs, or the amide of APICA and its analogs.
PB-22 has an EC50 of 5.1 nM for human CB1 receptors, and 37 nM for human CB2 receptors. PB-22 produces bradycardia and hypothermia in rats at doses of 0.3–3 mg/kg, suggesting potent cannabinoid-like activity. The magnitude and duration of hypothermia induced in rats by PB-22 was notably greater than JWH-018, AM-2201, UR-144, XLR-11, APICA, or STS-135, with a reduction of body temperature still observable six hours after dosing. One clinical toxicology study found PB-22 to be the cause of seizures in a human and his dog.
^Uchiyama, N.; Matsuda, S.; Kawamura, M.; Kikura-Hanajiri, R.; Goda, Y. (2013). "Two new-type cannabimimetic quinolinyl carboxylates, QUPIC and QUCHIC, two new cannabimimetic carboxamide derivatives, ADB-FUBINACA and ADBICA, and five synthetic cannabinoids detected with a thiophene derivative α-PVT and an opioid receptor agonist AH-7921 identified in illegal products". Forensic Toxicology. 31 (2): 223–240. doi:10.1007/s11419-013-0182-9.
^Gugelmann, H.; Gerona, R.; Li, C.; Tsutaoka, B.; Olson, K. R.; Lung, D. (2014). "'Crazy Monkey' Poisons Man and Dog: Human and canine seizures due to PB-22, a novel synthetic cannabinoid". Clinical Toxicology. 52 (6): 635–8. doi:10.3109/15563650.2014.925562. PMID24905571.