Inclusion Criteria:
1. Healthy participants aged 18 to 45 years (inclusive) at the time of signing the informed consent form.
2. Male participants with body weight ≥ 50.0 kg, female participants with body weight ≥ 45.0 kg, and body mass index (BMI) between 19 and 26 kg/m² (inclusive of both endpoints).
3. Female participants of childbearing potential who have not been surgically sterilized must use highly effective contraception from the time of signing the informed consent form until 1 month after the last dose of HRS-4642; male participants whose partners are women of childbearing potential must use highly effective contraception from the time of signing the informed consent form until 1 month after the last dose of HRS-4642. Female participants of childbearing potential who have not been surgically sterilized must have a negative serum HCG test within 14 days prior to the first dose, and must not be lactating.
4. Participants are able to communicate effectively with the investigator, understand and comply with all requirements of this study, and understand and sign the informed consent form.
Exclusion Criteria:
1. A history of or current presence of any clinically significant disease of the circulatory, endocrine, nervous, digestive, respiratory, urogenital, hematologic, immunologic, or psychiatric systems, or metabolic disorders, or any other condition that may interfere with the study results.
2. Poorly controlled or severe cardiovascular/cerebrovascular disease or arterial/venous thrombotic events within 6 months prior to study entry, such as cerebral hemorrhage, cerebral infarction, severe/unstable angina pectoris, symptomatic congestive heart failure (NYHA Class II-IV), myocardial infarction, arrhythmia requiring clinical intervention, deep vein thrombosis, etc.
3. Carotid ultrasound showing stenosis ≥ 50% (the ECST method is preferred) or presence of more than 2 high-risk plaques.
4. Surgery within 6 months prior to screening, or planned surgery during the study period.
5. Previous surgery affecting gastrointestinal absorption (including gastrectomy, bowel resection, gastric bypass/bariatric surgery, etc.), or need for gastric acid-neutralizing medications (e.g., aluminum hydroxide) during the study.
6. Blood donation or significant blood loss (≥ 400 mL), blood transfusion, or use of blood products within 3 months prior to screening.
7. Regular use of sedatives, hypnotics, or other addictive drugs; a history of drug abuse within 1 year prior to screening, or a positive urine drug abuse screen.
8. Participation in any clinical trial with administration of investigational drugs within 3 months prior to the first dose.
9. Smoking more than 5 cigarettes per day within 3 months prior to screening, and inability to stop using any tobacco products during the study period.
10. Regular alcohol consumption within 6 months prior to screening, defined as more than 14 units of alcohol per week (1 unit = 285 mL of beer, 25 mL of spirits, or 100 mL of wine), and inability to stop using any alcohol-containing products during the study period; positive breath alcohol test.
11. Clinically significant abnormalities in vital signs, physical examination, 12-lead electrocardiogram (ECG), abdominal ultrasound, chest X-ray, complete blood count, blood biochemistry, urinalysis, or coagulation tests during the screening period.
12. Positive hepatitis B surface antigen (HBsAg), positive hepatitis C antibody (anti-HCV), positive syphilis antibody, or positive HIV antibody.
13. History of needle phobia or blood-injection phobia, difficulty with blood collection, or inability to tolerate venipuncture blood sampling.
14. Pregnant or lactating women.
15. Participants with other factors deemed by the investigator to be unsuitable for participation in this study.
