Safety and Pharmacokinetics/ Pharmacodynamics of Methoxyethyl Etomidate Hydrochloride in Healthy Elderly Subjects

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.