biostudies-literatureUnknown44(1)He YFTPN171 is a novel phosphodiesterase-5 (PDE5) inhibitor used to treat pulmonary arterial hypertension (PAH) and erectile dysfunction (ED), which currently is undergoing phase II clinical trials in China. In this single-center, single-dose, nonrandomized, and open design study, radiolabeled [¹⁴C]TPN171 was used to investigate the metabolic mechanism, pharmacokinetic characteristics, and clearance pathways of TPN171 in 6 healthy Chinese male volunteers. Each volunteer was administered a single oral suspension of 10 mg (100 μCi) of [¹⁴C]TPN171. We found that TPN171 was absorbed rapidly in humans with a peak time (T_max) of 0.667 h and a half-life (t_1/2) of approximately 9.89 h in plasma. Excretion of radiopharmaceutical-related components was collecteActa pharmacologica Sinica221-233https://www.ebi.ac.uk/biostudies/studies/S-EPMC9813128biostudies-literaturePharmacokinetics, mass balance, and metabolism of [¹⁴C]TPN171, a novel PDE5 inhibitor, in humans for the treatment of pulmonary arterial hypertension.PMC9813128Yu CYYang FPYao XMLiu YLiu YMDuan HQDiao XXHe YFYu CShen JSLiu GYYu JHCheng HWang ZOdilov ATian GHfalsePharmacokinetics, mass balance, and metabolism of [¹⁴C]TPN171, a novel PDE5 inhibitor, in humans for the treatment of pulmonary arterial hypertension.TPN171 is a novel phosphodiesterase-5 (PDE5) inhibitor used to treat pulmonary arterial hypertension (PAH) and erectile dysfunction (ED), which currently is undergoing phase II clinical trials in China. In this single-center, single-dose, nonrandomized, and open design study, radiolabeled [¹⁴C]TPN171 was used to investigate the metabolic mechanism, pharmacokinetic characteristics, and clearance pathways of TPN171 in 6 healthy Chinese male volunteers. Each volunteer was administered a single oral suspension of 10 mg (100 μCi) of [¹⁴C]TPN171. We found that TPN171 was absorbed rapidly in humans with a peak time (T_max) of 0.667 h and a half-life (t_1/2) of approximately 9.89 h in plasma. Excretion of radiopharmaceutical-related components was collecte2023-01-01T00:00:00Z2023 Jan2026-04-29T02:25:25.025Z2025-04-20T09:26:30.522ZS-EPMC98131283567653110.1038/s41401-022-00922-6