Phase 1/2a Trial of YH12852 in Healthy Subjects and Patients With Functional Constipation

Inclusion Criteria: 1. Subjects must be willing and able to provide written informed consent. 2. BMI within the range 18 to 25 kg/m2. Exclusion Criteria: 1. History of positive serologic evidence for infectious disease including HBsAg, anti-HCV, anti-HIV. 2. Clinically significant lab/ECG abnormalities in the opinion of the investigator. 3. WOCBP who are unwilling or unable to use an adequate contraceptive method to avoid pregnancy for the entire study. WOCBP include any female who has experienced menarche and who has not undergone successful surgical sterilization (hysterectomy, bilateral tubal ligation, bilateral tubectomy, or bilateral oophorectomy) or is not postmenopausal. Post menopause is defined as amenorrhea for ≥ 12 consecutive months without another cause. Clinically acceptable contraceptive methods for this study: intrauterine devices (e.g., loop), physical barrier method (e.g., diaphragm, uterine cap, condom) with chemical barrier method (e.g., spermicide), sterile partner, practicing abstinence. 4. WOCBP who are willing to use hormonal methods or hormone-releasing device(e.g., mirena, implanon) for the entire study. 5. WOCBP who are pregnant or breastfeeding. 6. WOCBP with a positive pregnancy test prior to randomization. 7. Males who have not received a vasectomy must agree to use contraceptive methods defined in (a) and refrain from donating sperm throughout the study. 8. Presence of uncontrolled or severe medical illness. 9. Presence of a disease that require surgery at any time during the study.