The purpose of this study is to evaluate the safety and tolerability and pharmacokinetics of single doses of KLA478 in healthy volunteers；

This study is a single-center, randomized/non-randomized, single ascending dose（SAD）, Phase I clinical trial conducted in healthy subjects, divided into two parts:

Part 1 is an open-label single-dose study of active comparator to evaluate the pharmacokinetic characteristics of active comparator in healthy subjects； Part 2 is a randomized, double-blind, placebo-controlled single ascending dose study of KLA478: The purpose of this study is to evaluate the safety and tolerability and pharmacokinetics of single doses of KLA478 in healthy volunteers；

Inclusion Criteria:

1. Sign the informed consent form
2. Health participants (Age: 18~45 years);
3. Body Weight: Male≥50.0kg, Female≥45.0kg; 19 ≤BMI≤ 28.0kg/m2;
4. Clinical examination normal, or abnormal with no clinical significance；
5. Agreed to use contraception for 3-6 months.

Exclusion Criteria:

1. Allergy or Drug hypersensitivity;
2. Clinically significant Medical History；
3. Subjects with difficult venous blood collection/intolerance to venipuncture, or with a history of needle phobia/blood phobia；
4. Assess injection site abnormalities；
5. History of drugs that may interact with pramipexole within 1 month；
6. History of any Medication within 2 weeks；
7. Massive blood loss (> 200 mL) in the past 3 months；
8. History of any surgery within 3 months, or plan to undergo surgery during the trial；
9. History of any clinical study within 90 days；
10. History of any vaccine within 1 month，or Plan to get vaccinated during the trial period；
11. systolic blood pressure decreased ≥20 mmHg or diastolic blood pressure decreased ≥10 mmHg within 3 minutes from supine to upright position；
12. QTcF>450 ms；
13. Abnormal vital signs with clinical significance ；
14. Serum potassium level exceeds the reference range.；
15. Pre-transfusion test abnormal；
16. Lactation or pregnancy test positive ；
17. History of any drug abuse or positive drugs of abuse test result；
18. Previous alcohol abuse or unwillingness to stop drinking or alcohol breath test positive；
19. more than 3 cigarettes per day in 3 months, or unwilling to stop during the trial；
20. Intake of special diets that affect drug absorption, distribution, metabolism and excretion within 48 hours；
21. Have special requirements for diet；
22. Unprotected sexual behavior within 2 weeks;
23. engaged in driving vehicles, operating machinery, high-altitude work or other potentially dangerous behavior;
24. Inappropriate for participation in this trial as judged by the investigator.