This is a Phase I Clinical Study to Evaluate the Safety, Tolerability, and Pharmacokinetics of SSD8432 in Healthy Adult Subjects

108 healthy adult subjects (including 72 subjects in Part A to C, 16-24 subjects in Part D, and 8-12 subjects in optional Part E), including both males and females, will be enrolled in the phase I study.

This study will include Five parts: SSD8432 single dose and SSD8432 co-administrated with ritonavir (Part A), SSD8432 multiple dose (Part B), SSD8432 co-administrated with ritonavir multiple dose (Part C), SSD8432 co-administered ritonavir single dose in fasting and postprandial states (Part D: assessment of food effects) and optional part (Part E: Assessment of the safety and pharmacokinetics of SSD8432 in white healthy adult subjects)

Inclusion Criteria:

• Male subjects' weight ≥ 50 kg, female subjects' weight ≥ 45 kg; body mass index ≥ 19 kg/m2 and ≤ 28 kg/m2.
• Female participants of child-bearing potential must agree to use adequate contraception from screening until 1 months after last dose.

Exclusion Criteria:

• History of any other acute or chronic illness (including cardiovascular, pulmonary, neurological, hepatic, rheumatic, hematological, metabolic or renal disorders), or use of medication that, in the opinion of the Principal Investigator, may not suitable for participating in this study.
• Subjects with a history of hematophobia or trypanophobia and unable to tolerate intravenous indwelling needle blood sampling.
• History of dysphagia or any other gastrointestinal disease possibly affecting drug absorption.
• Take special diet and cannot abide by the provided food and corresponding requirements in this study.
• Subject with a history of clinically significant hypersensitivity reactions to the active substance of SSD8432 or ritonavir or to any other components of drug products.