A single intravenous injection of 0.8mg/kg or 2.8mg/kg Et-26-hcl was given to 18 subjects. The effect of plasma concentration on QT interval was evaluated by C-QTc effect model, and the pharmacokinetic characteristics and safety of ET-26 and etomidate acid were evaluated.

Inclusion Criteria:

1. Healthy adult male and female subjects;
2. Age: 18-45 years old;
3. Body weight: body mass index (BMI) between 19.0 and 28.0 kg/m2, with a body weight of at least 50 kg for male subjects and 45 kg for female subjects;
4. voluntarily sign informed consent;
5. Subjects were able to communicate well with investigators and complete the trial in accordance with the protocol.

Exclusion Criteria:

-

Auxiliary examination:

1. those with clinically significant abnormalities in comprehensive physical examination, vital signs, and laboratory tests (blood routine, blood biochemistry, coagulation function, urine routine, serum cortisol);

2. potentially difficult airway (modified Mallampati score III-IV);

3. abnormal and clinically significant hyperkalemia, hypokalemia, hypermagnesemia, hypomagnesemia, hypercalcemia, or hypocalcemia as judged by the investigator;

4. clinically significant abnormal 12-lead ECG, QTcF≥450 ms, PR interval ≥200 ms, QRS complex duration ≥120ms;

5. hepatitis B surface antigen, hepatitis C antibody, HIV antibody or syphilis antibody positive;

   Medication history:

6. use of any drugs that inhibit or induce hepatic drug-metabolizing enzymes within 30 days before screening (see Appendix 1 for details);

7. Use of any known QT-prolonging medication within 30 days before screening (see Appendix 1 for details);

8. use of any prescribed medication within 14 days before dose;

9. use of over-the-counter medications, Chinese herbal medicines, or food supplements such as vitamins and calcium supplements within 7 days before administration;

   History of disease and surgery:

10. have a history of any clinically serious diseases or diseases or conditions considered by the investigators to be likely to affect the results of the trial, including but not limited to a history of circulatory, respiratory, endocrine, nervous, digestive, urinary, or hematologic, immune, psychiatric, or metabolic diseases;

11. with a history of adrenal insufficiency, adrenal tumors, or hereditary heme biosynthesis disorders;

12. a history of severe cardiovascular disease, including but not limited to organic heart disease, such as heart failure, myocardial infarction, angina pectoris, or malignant arrhythmia, as judged by the investigator; Such as a history of torssion ventricular tachycardia, ventricular tachycardia, long QT syndrome or symptoms of long QT syndrome and family history (as indicated by genetic evidence or sudden death of a close relative at a young age due to cardiac causes);

13. underwent any surgery within 6 months before screening;

14. allergic constitution, such as known allergic history to two or more substances; Or who, as judged by the investigator, may be allergic to the trial drug or its excipients;

    Living habits:

15. heavy drinking or regular drinking in the 6 months before screening, i.e. drinking more than 14 units of alcohol per week (1 unit =360 mL of beer or 45 mL of 40% spirits or 150 mL of wine); Or with a positive alcohol breath test during the screening period;

16. used nicotine-containing products between 3 months before screening and study enrollment;

17. with drug abuse or drug abuse history within 3 months before screening; Or the urine drug test was positive in the screening period;

18. habitual consumption of grapefruit juice or excessive tea, coffee and/or caffeinated beverages and inability to quit during the trial;

    Others:

19. who had difficulty in blood collection or could not tolerate blood collection by venipuncture;

20. participated in any other clinical trial (including drug and device clinical trials) within 3 months before screening;

21. vaccinated within 1 month before screening or planned to be vaccinated during the trial period;

22. pregnant or lactating women;

23. during the trial and within half a year after the completion of the trial, or those who do not agree that the subjects and their spouses should take strict contraceptive measures during the trial and within half a year after the completion of the trial (see Appendix 4 for details);

24. had blood loss or donation > 400 mL within 3 months before screening, or received blood transfusion within 1 month;

25. had any factors considered by the investigator to preclude participation in the trial.