Evaluation of the acute effects of single‐dose TPN171 on semen quality in healthy Chinese male volunteers

Aims TPN171 is a novel phosphodiesterase type 5 inhibitor for the treatment of erectile dysfunction. This study aimed to assess the immediate impact of a single dose of TPN171 (10 mg) on semen quality in healthy male Chinese volunteers. Additionally, the study investigated the exposure of TPN171 in seminal plasma and observed the safety of TPN171 in the participants. Methods Eighteen healthy male volunteers were enrolled in this double‐blind, randomized, placebo‐controlled, 2‐period, 2‐sequence, crossover study. Semen samples were collected to compare semen parameters between the TPN171 and placebo groups. The concentrations of TPN171 were measured in seminal plasma and blood plasma to calculate the ratio of TPN171 concentration in seminal plasma to that in blood plasma, along with the exposure level and percentage of TPN171 in the seminal plasma. Results The administration of a single 10‐mg dose of TPN171 did not result in statistically significant effects on sperm motility, count, density, morphology, viscosity or volume in healthy male Chinese volunteers. The ratio of TPN171 concentration in seminal plasma to that in blood plasma was 0.72, with the amount of TPN171 in the seminal plasma measured at 78.5 ng. The percentage of exposure to the administered dose (10 mg) was 0.00085%. No adverse events were reported in the TPN171 group. Conclusion The findings indicate that a single oral dose of 10 mg TPN171 did not induce acute effects on semen quality in healthy male Chinese volunteers. The exposure of seminal plasma to TPN171 was <0.001% of the administered dose. Clinical Trial Registration Number NCT05585931.