This is a first-in-human study that will investigate the safety, tolerability and pharmacokinetics of single and multiple ascending doses of HRS-2261 using a double blind, placebo controlled, randomized study design. The influence of food on the pharmacokinetics of HRS-2261 and the effects of HRS-2261 on CYP3A4 metabolic enzymes will also be investigated.

Inclusion Criteria:

1. Able and willing to provide a written informed consent.
2. Age 18 to 55 years (inclusive).
3. Weight of male subjects ≥50 kg, female ≥45kg, body mass index (BMI) 19-26 kg/m2 (inclusive).
4. Medical examination (including physical examination, vital signs, laboratory examination, 12-lead electrocardiogram, abdominal B-ultrasound and chest radiography) normal or abnormal with no clinical significance.

Exclusion Criteria:

1. Any clinically serious diseases such as circulatory, endocrine, nervous, digestive, respiratory, blood, immune, mental and metabolic abnormalities or any other diseases that investigator determines may interfere with the test results.
2. Subjects with severe infection, severe trauma or major surgical operation within 3 months prior to screening; Subjects who plan to undergo surgery during the trial period and within two weeks after the trial.
3. Treated with any drug that inhibits or induces drug metabolism in the liver within 1 month prior to administration.
4. Subjects have any condition or medical condition that affects absorption, metabolism, and/or excretion of the study drug according to the investigator.
5. Subjects enrolled in clinical trials of any drug or medical device within 3 months prior to screening, or within 5 half-lives of the drug before screening.
6. Subjects who had a history of smoking in the previous 3 months (average daily smoking > 5 cigarettes), or who could not stop using any tobacco products during the test period.
7. Subjects who consumed more than 15g of alcohol per day on average (15g of alcohol is equivalent to 450 mL beer, 150 mL wine or about 50mL low-alcohol white wine) or tested positive for alcohol during the 3 months prior to screening, or who could not abstain from alcohol during the test period.
8. Subjects with a history of drug abuse, drug dependence or positive drug screening.
9. Determined by the investigator to be unfit to participate in this clinical trial.