Evaluate the Safety, Tolerability and Pharmacokinetics Characteristics of HPP737 in Healthy Volunteers

1. Signed informed consent and participated in the study voluntarily;

2. Male and female aged 45 to 18 years old;

3. Male or female who agree to take effective contraception from the screening period to 90 days after the last medication of the trial, and agree to take at least one effective contraceptive measure;

4. In the screening and baseline period, the body weight of male was no less than 50kg, and that of female was no less than 45kg. Body mass index (BMI) was in the range of 19-24kgm2(including 19 and 24), [BMI = weight (kg)) height2(M2)];

1. Have specific allergic history or allergic constitution such as drugs, food, pollen, etc., or be allergic to PDE4 inhibitors or similar drugs;

2. Patients with previous diseases of neuropsychiatric system, respiratory system, cardiovascular system, digestive system, haemolymph system, liver and kidney system, endocrine system, skeletal muscle system or other diseases, and the investigator judged that the previous medical history may have an impact on drug metabolism or safety;

3. Screening or baseline showing abnormal vital signs, physical examination, laboratory examination, electrocardiogram and other results with clinical significance;

4. Patients with history of malignant tumor in the past 5 years;

5. Abnormal chest X-ray or abdominal B-ultrasound with clinical significance;

6. Patients with positive HBsAg, HCV antibody, HIV antibody or syphilis antibody;

7. Having a history of drug dependence or drug abuse, or positive urine drug abuse screening;

8. Smokers (5 or more cigarettes a day);

9. Alcoholics (drinking more than 14 units per week, each unit is equivalent to 360ml beer or 150ml wine or 45ml liquor with 40% alcohol volume);