A Study of SSS17 in Healthy Subjects

The study will enroll healthy volunteers from a single academic medical center in China. All participants will be informed about the study and potential risks and required to provide written informed consent prior to undergoing study-related procedures. The improved Fibonacci dose escalation design will be implemented. The protocol specifies 10 mg, oral, one time for the first cohort without placebo control. Successive cohorts will be given doses up to 540 mg with placebo parallel control. Only no observation meets the criteria under stop rules, dose will escalate to the next higher level. The study will be divided into 2 stages: 1st period (fast) and 2nd period(fed). First period (fast): Subjects will be allocated 1:4 to receive placebo or SSS17, which will be administered by oral route. At each dose, tolerability, safety, PK and PD characteristics will be investigated. Second period (fed): in order to investigate the effects of food on PK and PD of SSS17. Subjects in one cohort will be administered again after meal on Day15. The accurate dose will be adjusted according to the findings in 1st period (fast)