In this trial, our primary goal is to investigate the safety of intravenous infusion of emulsified isoflurane. In order to protect volunteers, the investigators adopt the modified Fibonacci dose-escalation, starting from a very low dose which is derived from the 1/600 of acute LD50 in pre-clinic study. The trial will be terminated if half of volunteers develop severe adverse event in any dose group or any volunteer develop fatal adverse event in any group.

Inclusion Criteria:

• Age 18~45 years old (50:50 male:female) healthy volunteer;

• Body Mass Index (BMI) 19~24;

• health volunteers assessed by medical history and physical examination

  • systolic blood pressure between 100~140mmHg;
  • heart rate between 60~100bpm;
  • pulse oxygen saturation > 97% when inspiring air and reaching 100% after inspiring 100% oxygen for 5 min;
  • with normal result for routine lab test, including complete blood count, chemical test, urine test and stool test;

• Non-smoker and no history of alcohol or drug abuse;

• Fully understand the whole process of this trial and sign the informed consent.

Exclusion Criteria:

• Any history of allergy, especially to isoflurane or intralipid;
• Any suspected history of malignant hyperthermia in the volunteer or his/her relatives;
• Recent use of a medication with a pronounced effect on the central nervous system or any other organ (within 3 month)
• Recent participation in other clinical trial (within 1 month)
• Any history of difficult airway or suspected difficult airway;
• Pregnancy;
• Hyperlipidemia.