Evaluate the Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of RZ-629 in Healthy Subjects and T2D

Inclusion Criteria: 1. Sign the informed consent form (ICF) before the study, and fully understand the content, process and possible adverse reactions of the trial. 2\. Healthy male or female subjects between the ages of 18 and 65 years, inclusive. 3\. For part 1, part 2 and part 3 in healthy participants, minimum body weight is 50 kg for males, and 45 kg for females, have a BMI of 18 to 32 kg/m2, inclusive. For part 3 in T2D, BMI is between 25 to 40 kg/m2, inclusive. 4\. For part 1, part 2, and part 3 in healthy participants, fasting plasma glucose is between 3.9 mmol/L (70.2 mg/dL) and 6.1 mmol/L (109.8 mg/dL) at screening. For part 3 in T2D, glycosylated hemoglobin A1c (HbA1c) is between 6.5% and 10.5%, inclusive, and FPG ≤ 13.3 mmol/L at screening. 5\. For part 1, part 2, and part 3 in healthy participants, participants are in good health, with no clinically relevant acute or chronic medical conditions or severe diseases of the cardiovascular, gastrointestinal, hepatic, renal, endocrine, pulmonary, neurologic, psychiatric, respiratory, blood, immune or dermatological systems, as judged by the investigator. For part 3 in T2D, participants are diagnosed with T2DM for more than 1 year, and on a stable dose of dipeptidyl peptidase IV inhibitor (DPP-4i) monotherapy or DPP-4i + Metformin as their only anti-hyperglycemic treatment for at least 3 months prior to the screening visit. 6\. With no clinically significant findings from vital signs measurements, physical examination, clinical laboratory evaluations and 12-lead ECG, as judged by the investigator. 7\. Subjects must be willing to understand and comply with all research procedures and restrictions and be able to communicate effectively with researchers. Exclusion Criteria: 1. With a specific history of allergies or known to have multiple allergies. 2\. Have experienced acute illnesses within 2 weeks prior to the first dose or are taking concomitant medications. 3\. With a history or current presence of dysphagia or diseases that may potentially interfere with drug absorption or metabolism. 4\. Subjects and their first-degree relatives with a history of diabetes before screening. 5\. With a history of hypoglycemia or with impaired awareness or cognition of hypoglycemic symptoms within 3 months prior to screening. 6\. History of previous corrected QT interval (QTc) prolongation or clinically abnormal electrocardiogram (ECG) finding during screening. 7\. Have undergone major surgery within the past 6 months, or those planning to undergo surgery during the study period. 8\. Have used any medications and dietary supplements within 2 weeks prior to the first dose. 9\. Within 48 h prior to the first dose, have consumed food or beverages containing caffeine, alcohol, or concentrated tea, or those who have consumed special diets and/or purine-rich diets or have other factors that may affect drug absorption, distribution, metabolism, or excretion. 10\. Have received vaccinations within 4 weeks prior to the first dose or plan to receive vaccinations during the trial. 11\. Have participated in other clinical trials within 3 months prior to the first dose, or those planning to participate in other trials during the study period. 12\. Have donated blood and blood products (including plasma) within 3 months prior to the first dose or have experienced non-physiological blood loss of ≥ 400 mL within 6 months. 13\. Have consumed an average of more than 14 units of alcohol per week within the past 12 months prior to screening. 14\. Have smoked more than 5 cigarettes per day within the past 3 months or cannot stop using any tobacco products during the study. 15\. With a history of drug abuse within the past 12 months or positive drug abuse at screening. 16\. With positive results for serology of infectious diseases at screening. 17. Cannot tolerate venipuncture/indwelling needle or have a history of vasovagal syncope. 18\. Subjects deemed unsuitable for participation in this trial by the investigator due to other factors. 19\. With chronic or acute gastrointestinal inflammation. 20. Abnormal liver function tests: ALT or AST \> 2×ULN, or TBIL \> 1.5×ULN. 21. Use of drugs that may affect glucose metabolism (e.g., systemic steroids, nonselective β-blockers, monoamine oxidase inhibitors) within 1 month prior to screening.