G protein‐coupled receptor (GPCR) ligand prodrugs that can be released on demand with spatiotemporal control are powerful chemical tools that can assist in elucidating the consequences of GPCR activation or blockade at precise locations and times both in vitro and in vivo. Cannabinoid receptor prodrugs are of interest from both a drug delivery perspective and as tools to unravel the potential for differential signaling responses to be produced from cannabinoid receptor populations in distinct subcellular locations. Herein, the development and characterization of a cannabinoid type 2 receptor agonist prodrug is described, based on a 4‐diethylamino‐coumarylidenemalononitrilemethyl (DEACM‐MN) photo caging moiety linked via a carbonate to a chromenopyrazole cannabinoid ligand. This prodrug showed rapid photolysis with 450–455 nm light and good stability in biologically relevant buffer. The formation of various coumarin products alongside drug release was studied in different conditions. Radioligand binding assays were conducted with the prodrug, which revealed a significantly decreased human cannabinoid type 2 receptor binding affinity than the active chromenopyrazole parent ligand.

Cannabinoid Receptor 2 (CB2) is a promising target for treating inflammatory diseases. We designed derivatives of 3-carbamoyl-2-pyridone and 1,8-naphthyridin-2(1H)-one-3-carboxamide CB2-selective agonists with reduced lipophilicity. The new compounds were measured for their affinity (radioligand binding) and ability to elicit cyclic adenosine monophosphate (cAMP) signalling and β-arrestin-2 translocation with temporal resolution (BRET-based biosensors). For the 3-carbamoyl-2-pyridone derivatives, we found that modifying the previously reported compound UOSS77 (also known as S-777469) by appending a PEG2-alcohol via a 3-carbomylcyclohexyl carboxamide (UOSS75) lowered lipophilicity, and preserved binding affinity and signalling profile. The 1,8-naphthyridin-2(1H)-one-3-carboxamide UOMM18, containing a cis configuration at the 3-carboxamide cyclohexyl and with an alcohol on the 4-position of the cyclohexyl, had lower lipophilicity but similar CB2 affinity and biological activity to previously reported compounds of this class. Relative to CP55,940, the new compounds acted as partial agonists and did not exhibit signalling bias. Interestingly, while all compounds shared similar temporal trajectories for maximal efficacy, differing temporal trajectories for potency were observed. Consequently, when applied at sub-maximal concentrations, CP55,940 tended to elicit sustained (cAMP) or increasing (arrestin) responses, whereas responses to the new compounds tended to be transient (cAMP) or sustained (arrestin). In future studies, the compounds characterised here may be useful in elucidating the consequences of differential temporal signalling profiles on CB2-mediated physiological responses.