Inclusion Criteria:
1. To voluntarily sign the informed consent form before the study, and fully understand the content, process and possible adverse reactions of the study;
2. Ability to complete the study in accordance with the protocol requirements;
3. Participants (including male participants) must use effective contraceptive methods for 14 days prior to the first dose and voluntarily agree to maintain effective contraception from signing the informed consent until 3 months after the last dose, with no plans for pregnancy, sperm donation, or oocyte donation during this period. Specific contraceptive requirements are detailed in Appendix 1.
4. Male and female participants aged 18 to 55 years, inclusive;
5. Body weight ≥45.0 kg for female participants and ≥50.0 kg for male participants with a body mass index (BMI) between 18.0 and 30.0 kg/m2 (both inclusive).
Exclusion Criteria:
1. History or presence of any clinically significant disorder of the circulatory, endocrine, neurological, digestive, respiratory, genitourinary, hematological, immunological, psychiatric, and metabolic disorders or any other disease that could interfere with the results of the study;
2. Abnormal screening or check-in laboratory values including inadequate renal and hepatic function as assessed by the investigator (eGFR \<90 mL/min/1.73 m² calculated using CKD-EPI 2021 at screening, and total bilirubin, ALP, GGT, AST, and ALT outside normal range). A single repeat measurement is permitted for abnormal laboratory values for determining eligibility, at the discretion of the investigator.
3. Clinically significant abnormal physical examination, vital signs (systolic blood pressure \<90 mmHg or \>140 mmHg, diastolic blood pressure \<50 mmHg or \>90 mmHg; heart rate \<50 bpm or \>100 bpm; temperature 35.6°C to 37.7°C), ECG (QTcF \>450ms for males and \>470ms for females), or laboratory findings, as judged by the investigator. A repeat vital sign or ECG measurement, at the investigator's discretion, is acceptable for determining eligibility. Vital sign measurements may be repeated at Screening and/or Check-in, as required.
4. Participants with a history of specific allergies (such as urticaria, allergic asthma, etc.), or 2 or more types of allergens (such as drugs, foods such as milk and pollen), or allergies to any of soybeans, alcohol, eggs, or known allergies to components or analogues of this drug;
5. Hepatitis B surface antigen positive, hepatitis C antibody positive, or HIV antibody positive;
6. Women who are pregnant or breastfeeding, or who have a positive pregnancy test, or who are using long-acting contraceptives or implants other than those listed in Appendix 1;
7. Those who have difficulty in blood collection, or are unable to tolerate venipuncture, or have a history of fear of needles and hemophobia;
8. History of drug abuse within the past 5 years, or drug use within 3 months prior to screening, or positive urine drug screen;
9. Participants with past or current history or evidence of drug or alcohol abuse, or regular alcohol intake \>14 units per week for male participants and \>7 units per week for female participants (1 unit of alcohol = 150 mL of wine, 360 mL of beer, or 45 mL of alcohol 40%). Positive urine alcohol/ethanol test or urine drug screen at Screening or Day -1;
10. Those who smoked more than 5 cigarettes per day on average within 3 months before screening or those who refuse to quit using tobacco products during the confinement period;
11. Blood donation or significant blood loss (≥200 mL, excluding menstrual blood loss in females), receive blood transfusion, or blood product use within 3 months prior to the first dose;
12. History of hospitalization or surgery within 3 months prior to the first dose, or surgery planned during the study;
13. Participants who have participated in any clinical study and have taken any clinical study drug within 3 months prior to the first dose;
14. Use of any strong or moderate CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, nefazodone, troleandomycin, clarithromycin, ritonavir, nelfinavir, diltiazem, etc.) or strong CYP3A4 inducers (e.g., rifampin, carbamazepine, phenytoin, etc.) within 30 days prior to the first dose;
15. Currently used or recently discontinued the use of any contraindications that may pose safety risks on aprepitant and/or palonosetron within 3 months before screening including:
1. Pimozide (contraindicated with aprepitant due to QT prolongation risk);
2. Serotonergic medications (risk of serotonin syndrome with palonosetron);
3. Warfarin (documented INR decrease with aprepitant); and
4. QT-prolonging medications (increased cardiac risk with palonosetron).
16. Those who used any prescription drugs, over-the-counter drugs, vaccines, herbal medicines, or health products within 14 days before the first dose;
17. Those who have consumed grapefruits and products containing grapefruit ingredients or have strenuous exercise, or other factors affecting drug absorption, distribution, metabolism, excretion, etc. within 48 hours before receiving the study drug;
18. Those who have consumed any xanthine-rich foods (such as coffee, tea, chocolate, cocoa, cola, milk tea, etc.) within 48 hours before receiving the study drug;
19. Those who have special requirements for diet and cannot comply with the diet provided and corresponding regulations;
20. Participants may not be able to complete the study for other reasons or should not be included in the opinion of the investigator.
