This study is a phaseⅠstudy to determine the acute effects of TPN171H on semen function in healthy male subjects.

Safety Study in male subjects

Inclusion Criteria:

1. Male aged 18~40years (included)
2. Body Mass Index of 19 to 28 kg/m2; Body weight no less than 50 kg;
3. Sperm concentration ≥15*10^6/ml, Sperm motility(a+b(%))≥32%, Semen volume ≥1.5 ml, Liquefaction time≤60 min
4. Sperm sample should be collected after a minimum of 2 days and a maximum of 7 days of sexual abstinence.
5. Take reliable contraceptive measures
6. Physical examination, vital signs examination, laboratory examination, ECG were normal or abnormal without clinical significance;
7. Be able to understand and willing to sign the Informed Consent Form;

Exclusion Criteria:

1. People with azoospermia, teratozoospermia, moderate-to-severe asthenozoospermia, and moderate-to-severe oligozoospermia and other abnormal semen disease
2. People with vasectomy and ligation
3. People who have a history of hypersensitivity to other PDE5 inhibitors or TPN171H;
4. There are clear diseases of the central nervous system, cardiovascular system, digestive system (including those with severe fatty liver in B-ultrasound examination), respiratory system, urinary system, blood system, metabolic disorders, etc. and require medical intervention or other unsuitable clinical trials Those with tested diseases (such as history of mental illness, etc.); those with a history of orthostatic hypotension;
5. Blurred vision or a history of the following ocular diseases: nonvascular anterior ischemic optic neuropathy (NAION), abnormal color vision, hereditary retinal degeneration (such as retinitis pigmentosa), macular degeneration;
6. A history of fainting needles or fainting blood;
7. Blood loss or blood donation of 400 mL or more within 3 months before administration;
8. Those who have taken any prescription drugs, over-the-counter drugs, Chinese herbal medicines or health care products within 2 weeks before administration
9. those who have participated in other drug clinical trials and received trial drugs within 3 months before
10. Positive results of alcohol breath test, or current/previous alcoholics (drinking more than 21 standard units per week. 1 standard unit contains 14 g of alcohol, such as 360 mL of beer or 45 mL of 40% spirits or 150 mL wine);
11. Urine drug screening positive；
12. Smoking more than 10 cigarettes per day ；
13. Those who are positive for hepatitis B surface antigen (HBsAg), HCV antibody, syphilis antibody and HIV antibody;
14. he investigator believes that there are other factors that are not suitable for participating in this trial.