This is a first-in-human, Phase 1, single-center, randomized, single-blind, placebo-controlled, single dose-escalation study to evaluate the safety, tolerability, PK, PD of SSS17 following oral administration in healthy subjects. Approximately 65 subjects (53 receiving active drug and 12 receiving placebo) will participate in this study.

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)

Inclusion Criteria:

• Body weight≥50 for male or ≥45 for female, and BMI between 19.0-26.0 kg/m2
• Good general health as determined by the investigator based on medical history, physical examination, vital signs, 12-lead ECG, clinical laboratory tests and B-type ultrasound test.
• Participants of reproductive potential must agree to utilize reliable methods of contraception from screening to 6 months after the last administration of the study intervention. No plan for sperm (or egg) donation or pregnancy.
• Understand and sign the informed consent.
• Ability to understand and follow study-related instruction

Exclusion Criteria:

• A known allergy to any component of the SSS17 formulation, or allergy history of two kinds of drugs or food
• Medical history or conditions of digestive system.
• Female volunteers who are pregnant, menstrual, lactating or menopause with hormone therapy.
• Eyes diseases, including diabetic retinopathy, age-related macular degeneration.
• Vascular anomalies.
• Drug, alcohol or nicotine addiction.
• Blood donation or bleeding (more than 200 ml). Experience of treatment with EPO or blood transfusion.
• Any findings from the medical examination (including medical history, physical examination, vital signs, laboratory tests and ECG) deviating from normal and deemed by the investigator to be of clinical relevance
• Abnormal results in test of TIBC, serum iron or ferritin
• Acute diseases before administration.
• Other situations that the researcher believes may affect validity judgment or are not suitable for participation