Inclusion Criteria:
* Participants who meet all the following criteria could be enrolled in this study:
1. Written informed consent obtained from the participant in compliance with all local legal requirements.
2. Male or female participant aged between 18 and 60 years (extremes included).
3. Body mass index (BMI) between 18-32 kg/m2 (extremes included) and body weight less than 120 kg.
4. Males must use a condom or remain abstinent during the trial and for 3 months after their last dose of study medication. And a fertile man's female partner must not try to become pregnant during the study.
5. Female participants of childbearing potential must be established on a highly effective method of contraception (The recommended birth control methods are: Implantable (e.g. Implanon(r)), injectable (e.g. Depo-Provera(r)), insertable (e.g. NuvaRing®), Mirena (r) (LNG-IUS)), Combined oral contraceptives pill or progestin-only pill, Evra patch®, Intrauterine device (e.g. ParaGard(r), copper T) or Female sterilization, Male sterilization. The recommended birth control methods must be taken at least 3 weeks prior to screening (i.e., to ensure the contraceptive method has taken effect).) prior to dosing and until 3 months after their last dose in combination with male partner's use of a condom during the trial and for 3 months after the last dose.
6. Free from any clinically relevant illness or disease that may adversely affect the safety of the participant, or the integrity of the study as determined by medical history, physical examination, safety laboratory, and other assessments.
7. Participants must be willing and able to comply with scheduled visits, treatment plan, laboratory tests, and other study procedures. Without other intestinal diseases such as irritable bowel syndrome and acute diarrhea due to any infection.
Exclusion Criteria:
* If the participants meet any of the following criteria, they cannot be enrolled in this
1. Pregnant or breastfeeding women.
2. Participants with difficulty swallowing.
3. Severe infections requiring parenteral antibiotic therapy within 4 weeks before screening, such as sepsis or severe pneumonia.
4. Any clinically relevant conditions, such as cerebral stroke, myocardial infarction, heart failure, unstable angina pectoris, and severe cardiac arrhythmia within 6 months before screening.
5. Gastrointestinal, hepatic, or renal diseases or any other abnormalities known to interfere with drug absorption, distribution, metabolism, or excretion (within 6 months).
6. Supine blood pressure with systolic blood pressure outside the range of 90-140 mmHg and diastolic blood pressure outside the range of 40-90 mmHg, confirmed by repeat measurement at screening or baseline (Day -1) based on the Investigator's judgment.
7. Existing renal impairment (e.g., estimated glomerular filtration rate eGFR \<60 mL/min).
8. Presence of hepatic impairment: Child-Pugh A, B, or C and/or transaminase levels exceeding the upper limit of normal (i.e., serum total bilirubin \>= 1.5 x upper limit of normal \[ULN\], ALT or AST levels \> ULN).
9. Diabetes mellitus, regardless of control status at screening.
10. Hyperthyroidism or hypothyroidism.
11. Malignancy within 5 years, except for basal cell carcinoma of the skin, squamous cell carcinoma, or cured carcinoma in situ of the cervix.
12. Any major surgery within 6 months before screening.
13. Positive test results at screening for HBV (HBsAg positive), HCV (anti-HCV positive), or human immunodeficiency virus types I and II (anti-HIV I/II positive), or Treponema pallidum antibody (anti-TP positive).
14. Individuals with congenital or acquired immune system deficiency.
15. Resting heart rate outside the range of 40-100 bpm, confirmed by repeat measurement at screening or baseline (Day -1) based on the Investigator's judgment.
16. Participants with abnormal ECG at screening or baseline (Day -1). The inclusion of any participant with ECG abnormalities in the study must be approved by the Principal Investigator or a medically qualified Sub-Investigator with a signed record.
17. QT interval by Fridericia's correction method (QTcF) \>450 ms (male) or \>470 ms (female), or PR outside the range of 120-220 ms, confirmed by one repeat test at screening or baseline (Day -1) visit; or a history of risk factors for torsades de pointes (e.g., heart failure, hypokalemia, family history of long QT syndrome); or use of concomitant medications that prolong the QT/QTc interval.
18. History of severe psychiatric illness or currently receiving treatment for psychiatric illness; participants with prior epileptic seizures or convulsions (lifetime, except febrile convulsions), including absence seizures.
19. Use of any concomitant medication (including prescription drugs, over-the-counter drugs \[e.g., aspirin, acetaminophen, ibuprofen\], herbal medicines \[including traditional Chinese medicine products\], dietary supplements and cough syrups, prescription or over-the-counter antacids, etc.) within 14 days before study drug administration (or within 5 half-lives of the concomitant medication, whichever is longer).
20. Current use of strong inhibitors/inducers/substrates of CYP3A4, CYP3A5, and CYP2C8 with a narrow therapeutic index within 14 days before study drug administration.
21. Receipt of another investigational drug, biologic, or device therapy within 1 month after screening or within 5 half-lives of the study drug (whichever is longer).
22. Allergy to PA032 (active substance) or any excipient.
23. History of drug abuse, illicit drug use, or alcohol abuse within 1 year before screening (more than 14 units/week, 1 unit = 285 mL beer, or 250 mL spirits, or 125 mL wine) or unwillingness to abstain from alcohol and drugs (medications) throughout the entire study.
24. Regular use of nicotine-containing products (including but not limited to cigarettes, electronic cigarettes, pipes, cigars, chewing tobacco, nicotine patches, or nicotine gum) or positive urine cotinine test at baseline (Day -1). Occasional users of nicotine-containing products may participate but must avoid use during the screening period and throughout the study.
25. Positive urine drug test at screening.
26. Positive alcohol breath test at admission (Day -1).
27. Central nervous system, cardiovascular, pulmonary, hepatic, hematopoietic system diseases, renal, metabolic, gastrointestinal, urinary, immune, endocrine diseases, severe allergies, systemic allergic rash (including urticaria), psychiatric illness, evidence of abnormal liver function tests, evidence of abnormal renal function tests, or other abnormalities that may affect the participant's ability to participate or may confound the study results.
28. Poor peripheral venous access (defined as more than 3 failed puncture attempts).
29. Blood or plasma donation within 60 days before dosing. Participants who received blood product infusion within 90 days before screening.
30. Male participants planning to donate sperm or female participants planning to donate eggs (oocytes) during the study and within 3 months after the last dose.
31. Employees of the contract research organization, trial site, or sponsor, or immediate family members of employees.
