A Single-Center, Randomized, Open-Label, Two-Sequence, Two-Period, Crossover Study Comparing the Pharmacokinetics and Safety of Pyridostigmine Sustained-Release and Immediate-Release Tablets Following Single and Multiple Doses in Healthy Chinese Participants

Inclusion Criteria:

1. Aged between 18 and 45 years (inclusive), male or female;
2. Weight: male ≥50 kg, female ≥45 kg; body mass index (BMI) within the range of 19-26 kg/m² (inclusive);
3. Normal or abnormal without clinical significance in physical examination, vital signs, 12-lead electrocardiogram (ECG), laboratory tests, and chest X-ray;
4. Negative test results for hepatitis B surface antigen (HBsAg), hepatitis C virus antibody (HCV-Ab), human immunodeficiency virus antibody (HIV-Ab), and Treponema pallidum antibody;
5. No plans for childbearing or sperm/egg donation during the trial and for 3 months after the last dose, and willingness to use reliable contraceptive measures;
6. Ability to communicate well with the researchers, fully understand the purpose of the trial, comply with all requirements, voluntarily participate in the clinical trial, and provide written informed consent.

Exclusion Criteria:

1. Known history of allergy to the investigational drug or any of its components, or related preparations; history of allergic diseases or allergic constitution;
2. History of any disease that may affect the safety of the participant or the pharmacokinetics of the investigational drug, including but not limited to central nervous system, cardiovascular system, digestive system, respiratory system, urinary system, hematopoietic system, metabolic disorders (e.g., hyperkalemia), or other conditions unsuitable for clinical trials (e.g., psychiatric history), or history of mechanical intestinal obstruction, urinary tract obstruction, or bronchial asthma;
3. Chronic excessive consumption (more than 8 cups per day, 1 cup = 250 mL) of tea, coffee, or caffeine-containing beverages; or intake of any food or beverage containing caffeine, grapefruit, or poppy seeds (e.g., coffee, alcohol, strong tea, chocolate, grapefruit, pomelo, etc.) within 48 hours prior to the first dose;
4. Difficulty in blood collection or inability to comply with a standardized diet;
5. History of blood donation (including component blood donation) or blood loss ≥ 200 mL, or receipt of blood transfusion within 3 months prior to the first dose;
6. Smoking ≥10 cigarettes per day;
7. Positive alcohol breath test, or regular alcohol consumption (exceeding 21 units per week, 1 unit containing 14 g of alcohol, e.g., 360 mL of beer, 45 mL of 40% spirits, or 150 mL of wine) within 3 months prior to the first dose;
8. History of drug abuse or drug dependence, or positive urine drug abuse screening (morphine, tetrahydrocannabinol, methamphetamine, methylenedioxymethamphetamine, ketamine);
9. Use of any prescription drugs, herbal tonics, or any drugs that inhibit or induce liver drug metabolism within 1 month prior to the first dose, and/or use of any over-the-counter drugs or dietary supplements (including vitamins, calcium tablets, etc.) within 2 weeks prior to the first dose;
10. Participation in any other clinical trial and receipt of an investigational drug within 3 months prior to the first dose;
11. Lactating females or those with a positive pregnancy test (applicable to female participants);
12. Other factors deemed by the investigators to be unsuitable for participation in the trial