Medicinal Research Laboratories, Shionogi Pharmaceutical Research Center, 11-1 Futaba-cho 3-chome, Toyonaka, Osaka 561-0825, Japan.
Bioorg Med Chem. 2013 Jun 1;21(11):3154-63. doi: 10.1016/j.bmc.2013.03.030. Epub 2013 Mar 30.
The CB2 receptor has emerged as a potential target for the treatment of pruritus as well as pain without CB1-mediated side effects. We previously identified 2-pyridone derivatives 1 and 2 as potent CB2 agonists; however, this series of compounds was found to have unacceptable pharmacokinetic profiles with no significant effect in vivo. To improve these profiles, we performed further structural optimization of 1 and 2, which led to the discovery of bicyclic 2-pyridone 18e with improved CB2 affinity and selectivity over CB1. In a mouse pruritus model, 18e inhibited compound 48/80 induced scratching behavior at a dose of 100 mg/kg. In addition, the docking model of 18e with an active-state CB2 homology model indicated the structural basis of its high affinity and selectivity over CB1.
CB2 受体已成为治疗瘙痒和疼痛的潜在靶点，而不会产生 CB1 介导的副作用。我们之前发现 2-吡啶酮衍生物 1 和 2 是有效的 CB2 激动剂；然而，该系列化合物的药代动力学特征不佳，体内无明显作用。为了改善这些特征，我们对 1 和 2 进行了进一步的结构优化，发现双环 2-吡啶酮 18e 对 CB2 的亲和力和选择性优于 CB1。在小鼠瘙痒模型中，18e 在 100mg/kg 剂量下抑制了化合物 48/80 诱导的搔抓行为。此外，18e 与活性态 CB2 同源模型的对接模型表明了其对 CB1 具有高亲和力和选择性的结构基础。
