To evaluate the safety and tolerability of RSS0343 tablets in healthy subjects after single and multiple oral administration

Inclusion Criteria:

1. Age of 18-55 years old (inclusive), male or female;
2. Body mass index in the range of 19-28 kg/m2 (inclusive).

Exclusion Criteria:

1. The results of physical examination, vital signs, laboratory tests, chest imaging, abdominal B ultrasound and 12-lead electrocardiogram were abnormal.
2. Hepatitis B surface antigen, hepatitis C antibody, syphilis antibody, HIV antibody positive;
3. Suspected allergy to the study drug or any component of the study drug, or severe allergy to any drug, food, toxin or other exposure;
4. Current active, latent, or inadequately treated M. tuberculosis (i.e., tuberculosis [TB]) infection;
5. Investigator-assessed clinically significant infection (e.g., requiring hospitalization or parenteral antimicrobial therapy) within 1 month before screening; A history of more than one previous episode of herpes zoster, or disseminated herpes zoster (one episode); Any history of other infections that the investigator considered might have been aggravated by study participation.