Inclusion Criteria:
* Healthy adult aged ≥ 19 and ≤ 55 year-old at screening
* Body mass index (BMI) ≥ 19.0 kg/m2 and ≤ 27.0 kg/m2 with a body weight ≥ 45 kg at screening
* Those determined to be eligible for this study based on the findings of screening such as clinical laboratory tests (hematological test, blood chemistry test, blood coagulation test, urinalysis, test for viruses/bacteria, etc.), vital signs, and electrocardiogram (ECG) which are performed by the investigator according to the properties of medicines
* Those who have fully understood this clinical trial via detailed explanation, were willing to voluntarily participate in this study, and agreed to give written informed consent prior to the screening
* Those with a capability/willingness to participate throughout the study
Exclusion Criteria:
* Medical history or evidence of clinically significant blood, renal, endocrine, respiratory, gastrointestinal, urinary, cardiovascular, hepatic, psychiatric, neurological, musculoskeletal, oncological, or immune disease (except for history of simple dental treatment such as tartar, impacted teeth, and third molar teeth)
* Previous history of gastrointestinal disease (esophageal disease such as esophageal achalasia or esophageal stricture, inflammatory bowel disease (Crohn's disease, ulcerative colitis)) or surgery (except for simple appendectomy, hernia surgery, tooth extraction, etc.) which may affect drug absorption
* Sitting systolic blood pressure \< 90 mmHg or ≥ 140 mmHg or diastolic blood pressure \< 60 mmHg or ≥ 90 mmHg at screening
* Following findings of clinical laboratory tests:
* ALT or AST value \> twice the upper limit of normal (ULN)
* History of periodic alcohol consumption exceeding 210 g/week within 6 months prior to screening (beer (5%) 1 glass (250 mL) = 10 g, soju (20%) 1 glass (50 mL) = 8 g, wine (12%) 1 glass (125 mL) = 12 g)
* Has taken any other investigational product within 6 months prior to the first dose of investigational product
* History of serious alcohol or drug misuse and abuse within 1 year prior to screening
* Administration of drugs known to markedly induce or inhibit drug metabolizing enzymes within 30 days prior to the first dose of the investigational product
* Daily use of ≥ 20 cigarettes within 6 months prior to screening
* Administration of a prescription or non-prescription drug within 10 days prior to the first dose of the investigational product
* Whole blood donation within 2 months prior to the first dose of the investigational product or apheresis donation within 1 month prior to the first dose of the investigational product
* Subjects who received a blood transfusion within 1 month prior to the first dose of the investigational product
* Those who may be put at an increased risk due to the administration of the investigational product and study participation or have a severe acute/chronic medical or mental condition which may interfere with the interpretation of study results
* Subjects with a history of hypersensitivity (e.g., asthma, rhinitis, nasal polyps, urticaria, or allergic reactions) to the components of tegoprazan or naproxen, benzimidazole derivatives, aspirin, or other non-steroidal anti-inflammatory drugs (including COX-2 inhibitors)
* Subjects currently receiving medications containing atazanavir, nelfinavir, or rilpivirine
* Women with a positive pregnancy test, pregnant, or breastfeeding
* Subjects are unable to use a highly effective method of contraception (e.g., correctly placed intrauterine device(IUD), sterilization surgery (vasectomy, tubal ligation, etc.))
* Subjects unable to consume a high-fat diet provided during Part B of the clinical trial
* Subjects who are considered ineligible to participate in this study at the discretion of the investigator
