A Study to Investigate the Safety, Tolerability, Pharmacokinetics and Pharmacodynamics After Oral Administration of AJH-2947 in Healthy Korean and/or Caucasian Adult Male Subjects

Inclusion Criteria: Healthy Korean or Caucasian adult males aged 19 to 55 years at the time of written informed consent. Caucasian participants were defined as individuals born in Europe who had resided outside Europe for less than 10 years and whose parents and grandparents were all of European descent. Body weight between 50.0 kg and 90.0 kg and body mass index (BMI) from 18.5 kg/m² to less than 30.0 kg/m². Willingness to remain in the Clinical Trial Center (CTC) until discharge and to use sunscreen until the end of the study, including the post-study visit (PSV). Ability to understand the study after receiving a detailed explanation, voluntary agreement to participate, and provision of written informed consent before any screening examination. Considered suitable for participation by the investigator based on medical history, vital signs, 12-lead electrocardiogram (ECG), physical examination, and clinical laboratory test results obtained during screening. Exclusion Criteria: Clinically significant disease or a history of disease involving the liver, kidney, nervous system, immune system, respiratory system, digestive system, endocrine system, hematologic system, cardiovascular system, urinary system, psychiatric system, or other clinically relevant body system. For the multiple-dose trial, skin lesions or tattoos on both forearms, or hypersensitivity or allergic reactions to capsaicin cream that could affect pharmacodynamic evaluation. Gastrointestinal disease, including gastrointestinal ulcer, gastritis, gastric spasm, gastroesophageal reflux disease, or Crohn's disease, or a history of surgery that could affect the safety or pharmacokinetic evaluation of the investigational product, except for simple appendectomy or hernia repair. History of hypersensitivity to the active ingredient or other components of the investigational product, or to drugs of the same class. Positive screening result for hepatitis B virus (HBV), hepatitis C virus (HCV), syphilis (RPR), or human immunodeficiency virus (HIV). Supine systolic blood pressure below 80 mmHg or at least 140 mmHg, or diastolic blood pressure below 45 mmHg or at least 90 mmHg, measured after at least 3 minutes of rest. History of drug abuse or a positive urine drug screening result. Use of prescription medication or traditional herbal medicine within 2 weeks before the scheduled first dose, or use of over-the-counter medication, health-functional food, or vitamin supplements within 1 week before the scheduled first dose, or anticipated use of any such product during the study. Participation in another clinical trial, including a bioequivalence study, within 6 months before the scheduled first dose. Donation of whole blood within 2 months, donation of blood components within 1 month, or receipt of a blood transfusion within 1 month before the scheduled first dose. Excessive caffeine consumption of more than 5 units per day or inability to abstain from caffeine or caffeine-containing foods and beverages from 3 days before the expected first dose until the end of the study, including the PSV. Persistent alcohol consumption of more than 21 units per week, with 1 unit defined as 10 g of pure alcohol, or inability to abstain from alcohol from 3 days before the expected first dose until the end of the study, including the PSV. Smoking more than 10 cigarettes per day within the 3 months before the scheduled first dose or inability to stop smoking from screening until the end of the study, including the PSV. Inability to refrain from consuming grapefruit-containing foods from 3 days before the expected first dose until the end of the study, including the PSV. Planning a pregnancy during the study or within 90 days after the last administration of the investigational product, or unwillingness to use at least one medically acceptable contraceptive method. Acceptable methods included use of an intrauterine device with a proven failure rate by the participant's spouse or partner; concurrent use of barrier contraception and oral contraceptive pills; or surgical sterilization of the participant or partner, including vasectomy, salpingectomy, tubal ligation, or hysterectomy. Considered unsuitable for participation by the investigator for any other reason, including clinical laboratory test results.