Tolvaptan oral administraction phase I PK clinical trial. Two groups of healthy male subjects. One group receives single dose of Tolvaptan. The other group receives multi dose of Tolvaptan.

Inclusion Criteria:

1. Healthy male volunteers.
2. Aged 18 to 40 years old.
3. Weight no less than 50kg and within the range of standard weight (body mass index between 19 and 24).
4. Auxiliary examinations: blood routine and coagulation, urine routine, blood biochemistry (total protein, albumin, blood glucose, total bilirubin, AST (GOT), ALT (GPT), ALP, γ-GTP, LDH, CK (CPK), total cholesterol, triglycerides, urea nitrogen, creatinine, uric acid, Na, K, Cl, Mg, Ca, P), hepatitis B surface antigen, hepatitis C antibody, HIV antibody, syphilis antibody, 12-lead electrocardiogram, 24-hour ambulatory electrocardiogram (Holter) examination, all items are normal.
5. Signed the informed consent form.

Exclusion Criteria:

1. The patient has a history of heart, liver, kidney, digestive tract, metabolic, respiratory, blood, mental, nervous system and other disorders, and the doctor's judgment is not suitable.
2. Hepatitis B virus, syphilis, hepatitis C virus, HIV infection.
3. Patients with a history of clinically significant arrhythmias of various types, including rapid and slow types, such as atrioventricular block, sinus arrest, and supraventricular tachycardia, were assessed by the investigators.
4. He has a history of postural hypotension (blood pressure drop ≥20/10mmHg when he changes from lying position to standing position, accompanied by dizziness and other symptoms), standing dizziness, collapse, fainting, and vertigo.
5. Quiet for more than 3 minutes, sitting pulse below 55 beats/min or more than 90 beats/min.
6. Quiet for more than 3 minutes, sitting systolic blood pressure is lower than 100mmHg or higher than 140mmHg; Diastolic depression of 60mmHg or higher than 90mmHg.
7. Various voiding disorders (frequent urination, or difficulty urinating, etc.).
8. Have a family history of genetic diseases (including a history of genetically predisposed arrhythmias in relatives).
9. A history, allergy or propensity to be allergic to drugs or any other substance.
10. Smokers, alcoholics, or other drug addicts.
11. Physical examination had clinically significant positive findings.
12. People who have donated blood or been sampled as a subject within the last 3 months.
13. People who have taken prophylactic or therapeutic drugs in the last 2 weeks.
14. Otherwise, the clinical trial physician or the clinical trial physician determines that the safety of the trial is affected.