The goal of this clinical trial is to assess the safety, tolerability, and pharmacokinetic profiles of Y-3 in healthy adult volunteers in the United States. The main questions it aims to answer are:

• What the pharmacokinetic profiles of single ascending doses of Y-3 (40 mg and 60 mg) in the US healthy adult volunteers?
• If drug Y-3 (40mg and 60 mg) is safe and tolerate in the US healthy adult volunteers.

Researchers will compare drug Y-3 (40 mg and 60 mg) to a placebo (a look-alike substance that contains no drug) to see what the pharmacokinetic profiles of single ascending doses of Y-3 (40 mg and 60 mg) in the US healthy adult volunteers and if drug Y-3 (40mg and 60 mg) is safe and tolerate in the US healthy adult volunteers.

Participants will:

• Take drug Y-3 (40 mg) or Y-3 (60 mg) or a placebo only once.
• Answer questions regarding your medical history.
• Comply with the study procedures and requests.
• Complete all tests and collections of PK Sampling.
• Must not have any special dietary requirements and be able to consume the food (low-fat) provided by Tranquil Clinical Research during your 4-night stay.
• Must avoid excessive ( > 8 cups per day) caffeine consumption (i.e. coffee or tea) during your time in the study.
• Must not consume any food or beverage rich in grapefruit, papaya, or mango during your time in the study.
• Must not take any other medications, including traditional Chinese medicines and herbal medicines, during your time in the study.
• Must avoid sexual activity or use non-drug contraceptive measures (i.e. condoms) during your time in the study.
• Female participants must not become pregnant while in the study.
• Must not receive any vaccinations during your time in the study.
• Must not donate blood for purposes outside of study procedures during your time in the study.
• Must not drink alcohol during your time in the study.
• Must not smoke during your time in the study.
• Inform your Study Doctor if you no longer wish to participate in the study.

Inclusion Criteria:

1. Medically documented as healthy at the time of screening as determined by their medical history, medical assessment, physical examination, 12-lead electrocardiogram (ECG), and clinical laboratory tests, etc.
2. Within 18-45 years at the time of informed consent, inclusive.
3. Body weight ≥ 50 kg for male and ≥ 45 kg for female, body mass index (BMI) within the range of 19 - 28 kg/m2, inclusive.
4. Fully understand and provide a signed informed consent before performing any study-related procedures.
5. Comply with the study and follow-up procedures.

Exclusion Criteria:

1. Known allergy to Y-3 or any of its excipients.
2. Have disease history or current disease that may affect the safety evaluation of the subject or the internal process of the study drug, that the investigator judged to be of clinical significance, including the cardiovascular system, endocrine system, central nervous system, digestive system, respiratory system, hematological system, immunology, psychiatry, metabolic abnormalities, etc.
3. Clinically significant abnormal 12-lead electrocardiograms (ECG) and vital signs judged by the investigator.
4. Clinically significant abnormal laboratory tests (hematology, serum chemistry, coagulation, urinalysis, etc.) and other screening tests judged by the investigator.
5. Test positive for hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV) antibody, syphilis antibody or human immunodeficiency virus (HIV) antibody.
6. Alcoholics or regular drinkers within 6 months prior to screening, that is, those who drink more than 14 units of alcohol per week (1 unit = 360 mL of beer or 45 mL of alcohol with 40% alcohol content or 150 mL of wine), or whose alcohol breath test results are greater than 0.0 mg/100 mL, or who cannot abstain from alcohol during the study.
7. Smokers, that is, those who smoke more than 3 cigarettes per day within 3 months prior to screening, or those who cannot comply with the prohibition of smoking during the study.
8. Current or former drug users, or positive urine screen for drugs of abuse at screening.
9. Have special requirements for diet and cannot follow the unified diet.
10. Drink too much tea, coffee and/or caffeine-containing beverages (more than 8 cups, 1 cup = 250 mL) every day within 3 months prior to screening, or who have consumed any diet (food or beverage) rich in grapefruit, pitaya and mango within 14 days prior to screening.
11. Have taken any prescription drug or over-the-counter drug, traditional Chinese medicine or herbal medicine, health products within 14 days prior to screening, or 5 half-lives, whichever is longer, before the first dose of study drug, or have received vaccine inoculation within 14 days prior to screening; or plan to inoculate vaccine during the study.
12. Participated in any other clinical trials within 3 months prior to screening.
13. Donation or loss of blood equal to or in excess of 200 mL within 3 months prior to screening.
14. Female subjects who have unprotected intercourse within 14 days prior to screening, or pregnant or lactating women.
15. Male subjects (or their partners) or female subjects have baby plans during the whole trial period and within 3 months after the end of the trial, or subjects are unwilling to take one or more non-drug contraceptive measures (such as complete abstinence, condoms, ligation, etc.) during the study.
16. Subjects voluntarily withdraw from the study due to personal reason, or subjects who the investigator believes are not suitable for enrollment for other reasons.
17. Suicidal ideation, history of suicidal behavior, or history of psychiatric comorbidities.

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