Taranabant is a highly potent and selective cannabinoid 1 receptor inverse agonist. Taranabant inhibits the binding and functional activity of various agonists (Ki: 0.13 nM for the human CB1R in vitro).
Taranabant is a highly potent and selective cannabinoid 1 receptor inverse agonist. Taranabant inhibits the binding and functional activity of various agonists (Ki: 0.13 nM for the human CB1R in vitro).
Taranabant is determined to be an inverse agonist (EC50=2.4±1.4 nM), in a functional assay of cyclic-AMP production. Taranabant is an exceptionally potent and selective CB1R inverse agonist with >500-fold improvement in affinity over the original lead. Taranabant is a CB1R inverse agonist with minimal potential for covalent protein binding. Taranabant binds to human or rat CB1R (IC50: 0.3 and 0.4 nM and a Ki: 0.13 and 0.27 nM, respectively). Taranabant binds to the human or rat CB2R (IC50: 290 and 470 nM and Ki: 170 and 310 nM, respectively). The selectivity ratio of CB1R over CB2R is approximately 1000-fold. IC50s of Taranabant for CB1R and CB2R by substituted amides are 0.3±0.1 nM, and 290±60 nM, respectively [1][2].
Taranabant dose-dependently inhibits food intake and weight gain, with an acute minimum effective dose of 1 mg/kg in diet-induced obese rats. Taranabant dose-dependently inhibits 2 h and overnight food intake as well as overnight gains in body weight in C57BL/6N mice. Taranabant (p.o., 1- and 3-mg/kg doses) treatment significantly inhibits 2-h food intake (36 and 69% reductions, respectively; P<0.05 and P<0.00001, respectively) and overnight food intake (13 and 40% reductions, respectively; P<0.05 and P<0.00001, respectively) as well as overnight gains in body weight (48 and 165% reductions, respectively; P<0.01 and P<0.00001, respectively). Taranabant has a good pharmacokinetic profile in three species (rat, 1 mg/kg i.v., 2 mg/kg p.o., F=74%, t1/2=2.7 h; dog, 0.2 mg/kg iv, 0.4 mg/kg p.o., F=31%; t1/2=14 h; rhesus monkey, 0.2 mg/kg i.v., 0.4 mg/kg p.o., F=31%, t1/2=3.6 h) and good brain exposure (1 mg/kg iv, brain and plasma concentrations of 0.11 and 0.18 μM at 1 h, respectively) [1][2].