Inhibition of thymic stromal lymphopoietin (TSLP) is a promising therapeutic strategy for the treatment of allergic diseases. This study aimed to characterize the drug metabolism and pharmacokinetic properties of TFV-1, a novel flavonoid analogue and potent TSLP inhibitor. Metabolic stability, plasma protein binding, and the chemical stability of its glucuronide metabolite were evaluated in vitro. Pharmacokinetic parameters were determined in mice after intravenous, oral, and subcutaneous administration. Additionally, hepatic clearance was predicted using in vitro-in vivo extrapolation (IVIVE). TFV-1 exhibited low systemic clearance and a long half-life in mice. This was attributed to its extremely high plasma protein binding (fraction unbound, f_u<0.5%), supported by IVIVE analysis classifying it as a 'low clearance' compound. TFV-1 was stable against NADPH-dependent metabolism and appeared to be cleared primarily via glucuronidation. Its glucuronide metabolite was stable in pH 7.4 phosphate buffer, suggesting a low risk as a reactive metabolite. The oral bioavailability was low (5.7%) but increased to 19.9% with subcutaneous administration. This difference is likely due to its low intestinal solubility and first-pass metabolism in the gastrointestinal tract and liver. In conclusion, this study successfully characterized the drug metabolism and pharmacokinetic properties of the novel TSLP inhibitor TFV-1. These findings provide a crucial foundation for the subsequent optimization of TFV-1 to develop a new drug candidate with favorable drug-like properties.