Development of Novel Alkoxyisoxazoles as Sigma-1 Receptor Antagonists with Antinociceptive Efficacy

A novel series of sigma (sigma) receptor ligands based on an alkoxyisoxazole scaffold has been designed and synthesized. Preliminary receptor binding assays identified highly potent (K-i < 1 nM) and selective sigma 1 ligands devoid of binding interactions with the monoamine transporters DAT, NET, and SERT. In particular, compound 53 was shown to possess significant antinociceptive activity in the mouse formalin-induced inflammation pain model when administered intraperitoneally at 40 and 80 mg/kg. Initial pharmacokinetics evaluation indicated an excellent brain exposure following oral dosing in mice, suggesting that further investigation into the use of alkoxyisoxazoles as sigma 1 ligands for antinociception is warranted. This study supports the notion that selective sigma 1 antagonism could be a useful strategy in the development of novel antipain therapy.