DEVELOPING DUAL INHIBITORS OF FATTY ACID AMIDE HYDROLASE AND SOLUBLE EPOXIDE HYDROLASE FOR THE TREATMENT OF CHRONIC PAIN

Fatty acid amide hydrolase (FAAH) and soluble epoxy hydrolase (sEH) are two enzymes responsible for hydrolyzing AEA (AEA) and epoxyeicosatrienoic acids (EETs), respectively. AEA, an endogenous cannabinoid, is proven to produce an analgesic effect when binding to the CB1 endocannabinoid receptor. This pain-relieving process is terminated when hydrolysis takes place breaking down AEA to arachidonic acid metabolites. Epoxyeicosatrienoic acid, a bioactive lipid, is prevalent in human organs and has been taken as an anti-inflammatory marker. EETs are metabolites of arachidonic acids produced from the aforementioned FAAH hydrolysis and other lipids hydrolysis. Similar to AEA, EETs can be hydrolyzed by sEH enzyme leading to the loss of analgesic effect. Therefore, inhibiting these two enzymes FAAH and sEH, is necessary for alleviating pain. In this research, we aimed to develop a multi-targeted directed ligand that can inhibit FAAH and sEH simultaneously in treating chronic pain. Here, we have synthesized a library of 15 compounds with the assistance of microwave synthesis and evaluated them through in silico molecular modeling and in vitro enzyme assay. The best candidate was additionally tested in vivo on a rat model of nociceptive pain. In conclusion, compound 4f showed competitive activity in suppressing FAAH and sEH enzymes with moderate solubility and microsomal stability. Compound 4f showed an anti-hyperalgesia effect at 3mg/kg in the rat model of the orofacial hyperalgesia pain model. Compound 4o demonstrated exceptional results in enzyme assay, showing promising potential. Future work will consider further compound 4o and related compounds in the library.