The purpose of this study is to evaluate the safety and tolerability and pharmacokinetics of single and multiple doses of KLA578-1 for injection in healthy volunteers

"The study will be carried out in 2 parts. Part 1: This is a open-label, single ascending dose (SAD) escalation study with a total of 3 dose groups, i.e., Groups 1 to 3. There are a total of 12 volunteers in each group with a similar male to female ratio. Groups 1 and 3 are single-arm study, all volunteers will receive the experimental drug ""KLA578-1 for Injection"" ; Group 2 is a randomized, two-treatment, two-period, crossover study, 12 volunteers will be randomized to TR sequence or RT sequence with 6 volunteers in each sequence. The experimental drug ""KLA578-1 for injection"" will be administered in the TR sequence of Period 1, the control drug ""Etopcoxib Tablets"" will be administered to the RT sequence. After 7 days of washing, the control drug ""Etocoxib Tablets"" will be administered in the TR sequence, and the experimental drug ""KLA578-1 for Injection"" will be administered in the RT sequence.

Part 2: This is a open-label, single-arm multiple dose study. A dose group is temporarily set up, with a total of 12 volunteers enrolled, and the male-to-female ratio will be similar. Volunteers will receive the experimental drug ""KLA578-1 for Injection"" 120 mg once daily (every 24 h ± 2 min with reference to the dosing time on D1) under fasting conditions (fasting for at least 10 hours) from D1 to D5; Drinking water is prohibited from 1 h before each dose to 1 h postdose, and fasted within 4 hours after dosing on D1 and D5."

Inclusion Criteria:

1. Health Volunteers (Age: 18~45 years);
2. Body Weight: Male≥50.0kg, Female≥45.0kg; 19.0 ≤BMI≤ 26.0;
3. There were no abnormalities in clinically significant physical examination, vital signs, 12-lead electrocardiogram, laboratory tests;
4. Heart rate ≥ 60 bpm and pulse ≥ 60 beats/min.

Exclusion Criteria:

1. Allergy or Drug hypersensitivity;
2. Clinically significant Medical History;
3. Gastrointestinal ulcers or gastrointestinal bleeding;
4. History of any surgery within 4 weeks;
5. History of any Medication within 14 days;
6. History of any inducers or inhibitors of major CYP450 enzymes within 30 days;
7. History of any clinical study within 3 months;
8. History of any vaccine within 1 month;
9. History of any drug abuse;
10. Tablet dysphagia;
11. Needle sickness, Hematosickness;
12. Massive blood loss (> 200 mL) in the past 3 months;
13. Female volunteers are pregnant or lactating;
14. History of unprotected sex within 2 weeks;
15. Special requirements for diet;
16. Heavy smoker ( more than 3 cigarettes/day) within 3 months;
17. History of alcohol abuse,or heavy alcohol intake (more than 14 units a week) within 6 months;
18. Heavy caffeine intake;
19. History of grapefruit, xanthine-rich foods intake within 7 days;
20. Positive alcohol test;
21. Positive drugs of abuse test result.