16 subjects were divided into two groups: One group consisted of healthy non-elderly subjects aged 18-64 years (including boundary value). The other group was healthy elderly subjects, aged ≥65 years old, of which no less than 3 cases were ≥75 years old, with 8 subjects in each group.Healthy non-elderly subjects will be included as matched control subjects. The gender of healthy non-elderly subjects was consistent with that of healthy elderly subjects. The mean body weight of the healthy non-elderly subjects was within the range of the mean body weight of the healthy elderly subjects ±10 kg.

All patients received a single intravenous injection of 0.8mg/kg ET-26. To evaluate the pharmacokinetic characteristics of ET-26 and provide guidance for the clinical application of ET-26-hcl.

Inclusion Criteria:

1. healthy adult male and female subjects aged ≥18 years;
2. Body weight: body mass index (BMI) between 19.0 and 28.0 kg/m2 (including the cut-off value), with a body weight of at least 50 kg for male subjects and 45 kg for female subjects;
3. Blood pressure of healthy subjects should be between 90-139/60-89 mmHg, heart rate and pulse should be between 55-100 beats/min
4. The subjects had good communication with the investigators, signed the informed consent form voluntarily, and were able to complete the trial according to the protocol.

Exclusion Criteria:

-

Auxiliary examination:

1. If the results of physical examination, vital signs, color Doppler echocardiography (only for healthy elderly subjects), cortisol test, laboratory tests (blood routine, blood biochemistry, coagulation function, urine routine) and 12-lead electrocardiogram were abnormal and clinically significant by investigator evaluation;

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

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

   Medication history:

4. use of any drugs that inhibit or induce hepatic drug-metabolizing enzymes within 30 days before screening;

5. use of any prescribed medication within 14 days before dosing;

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

   History of disease and surgery:

7. 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;

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

9. patients who underwent any surgery within 6 months before screening;

10. 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:

11. binge drinking or regular drinking in the 6 months before screening, i.e. 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 at baseline;

12. if they smoked more than 5 cigarettes per day in the 3 months before screening or could not quit smoking during the study;

13. with drug abuse or drug abuse history in the past three months; Or the baseline urine drug test was positive;

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

    Others:

15. those who have difficulty in blood collection, can not tolerate venipuncture, and can not tolerate arterial blood collection (e.g. Allen's test positive);

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

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

18. pregnant or lactating women;

19. those who planned to give birth or donate sperm during the trial and half a year after the completion of the trial, or those who did not agree that the subjects and their spouses should take strict contraceptive measures during the trial and half a year after the completion of the trial;

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

21. subjects with any factors considered by the investigator to be ineligible for the trial.