Disposition, profiling and identification of emixustat and its metabolites in humans

Abstract1. Emixustat is a small molecule that potently inhibits retinal pigment epithelium 65 isomerohydrolase. Emixustat is in clinical development for the treatment of various retinopathies (i.e. Stargardt disease and diabetic retinopathy).2. A human absorption, distribution, metabolism, and excretion (ADME) study was conducted with a single dose of [14C]-emixustat in healthy male subjects. Total 14C content in plasma, urine, and faeces was determined using accelerator mass spectrometry (AMS), and metabolic profiles in pooled plasma and urine were investigated by both HPLC-AMS and 2D LC-MS/MS.3. After a single, oral 40-mg dose of [14C]-emixustat, recovery of total 14C was nearly complete within 24 h. Urine was the major route of 14C elimination; accounting for > 90% of the administered dose.4. Biotransformation of emixustat occurred primarily at two structural moieties; oxidation of the cyclohexyl moiety and oxidative deamination of the 3R-hydroxypropylamine, both independently and in combination to pro...