Low brain penetrant CB1 receptor agonists for the treatment of neuropathic pain.

Novel, low brain penetrant, orally bioavailable CB1 receptor agonists were designed starting from a mature lead series of potent brain penetrant CB1 receptor agonists. Increasing the calculated polar surface area was found to be a good strategy for reducing brain penetration whilst retaining drug-like properties. This in silico approach led to the discovery of LBP1, an orally bioavailable, low brain penetrant CB1 receptor agonist with robust activity in rodent models of neuropathic pain and a good preclinical therapeutic profile, which was selected for clinical development.

Design, synthesis and structure-activity relationships of (indo-3-yl) heterocyclic derivatives as agonists of the CB1 receptor. Discovery of a clinical candidate.

We report an expansion of the structure-activity relationship (SAR) of a novel series of indole-3-heterocyclic CB1 receptor agonists. Starting from the potent but poorly soluble lead, 1, a rational approach was taken in order to balance solubility, hERG activity and potency while retaining the desired long duration of action within the mouse tail flick test. This led to the discovery of compound 38 which successfully progressed into clinical development.

Discovery of potent and orally bioavailable heterocycle-based cannabinoid CB1 receptor agonists.

Novel 3-(1H-indol-3-yl)-1,2,4-oxadiazoles and -thiadiazoles were synthesized and found to be potent CB1 cannabinoid receptor agonists. The oral bioavailability of these compounds could be dramatically improved by optimization studies of the side chains attached to the indole and oxadiazole cores, leading to identification of a CB1 receptor agonist with good oral activity in a range of preclinical models of antinociception and antihyperalgesia.

Design, synthesis, and structure-activity relationships of indole-3-heterocycles as agonists of the CB1 receptor.

Novel indole-3-heterocycles were designed and synthesized and found to be potent CB1 receptor agonists. Starting from a microsomally unstable lead 1, a bioisostere approach replacing a piperazine amide was undertaken. This was found to be a good strategy for improving stability both in vitro and in vivo.

Design, synthesis, and structure-activity relationship study of bicyclic piperazine analogs of indole-3-carboxamides as novel cannabinoid CB1 receptor agonists.

Bicyclic piperazine derivatives were synthesized as conformationally constrained analogs of N-alkyl piperazines and were found to be potent CB1 receptor agonists. The CB1 receptor agonist activity was dependent upon the absolute configuration of the chiral center of the bicyclic ring system. Although the conformational constraint did not protect the compounds from metabolism by N-dealkylation, several bicyclic analogs were found to be more potent than the unconstrained lead compound.