The purpose of this study is to compare and evaluate impact on pharmacodynamic characteristics of CJ-12420 and dexlansoprazole with evening dosing in healthy male volunteers

Evaluation Criteria:

1. Pharmacokinetic Endpoints Cmax, tmax, AUClast of CJ-12420
2. Pharmacodynamics Endpoints Time pH > 4 Time pH > 6 Integrated acidity Percent inhibition of integrated acidity Percent inhibition time gastric pH ≤ 4 Median pH
3. Safety Assessments Physical examination, ECGs, vital signs (blood pressure, heart rate, body temperature), laboratory test (CBC, Chemistry, UA), and adverse events (AEs)

Inclusion Criteria:

1. Healthy male volunteers aged ≥20 to ≤45 years

2. Body mass Index (BMI) of 19 to 28kg/m2 ; and a total body weight ≥ 50kg

3. Medically healthy without clinically significant vital signs (blood pressure in sitting position, heart rate)

   • 90 mmHg ≤ Systolic blood pressure (SBP) ≤ 140 mmHg
   • 50 mmHg ≤ Diastolic blood pressure (DBP) ≤ 95 mmHg
   • 45 (beats/min) ≤ Heart rate ≤ 95 (beats/min)

4. Understand restriction during the study and voluntarily consent to participate in the study

5. Consent to use the effective contraceptive methods (using abstinence, spermicide, and condom) and not to donate sperm during the study and until 30 days after completion of study

6. Non-smoker or ex-smoker who stopped smoking for at least one year

7. Negative H. pylori result in urea breath test (UBT)

Exclusion Criteria:

1. History of clinically significant diseases in the digestive, kidney, liver, nervous, hemato-oncologic, endocrine, respiratory, immune, psychiatric, musculoskeletal, or cardiovascular system and other diseases that may harm safety of the subject or may affect the validity of study results, in the judgment of investigator
2. History of allergy or hypersensitivity to any drugs including serious adverse events from treatments such as PPI (omeprazole, rabeprazole, lansoprazole) or P-CAB
3. History surgery that may affect absorption, distribution, metabolism, and elimination of the study drug or in such a medical condition, at the discretion of the principal investigator or sub-investigator
4. History of use of another investigational product within 90 days prior to screening visit
5. Donation of a unit of whole blood within 60 days or blood components or transfusion within 30 days prior to screening visit
6. Having special diet or changes in dietary habits within 30 days prior to screening visit
7. Use of prescription drug within 14 days or over-the-count (OTC) drug including herbal medicine within 7 days prior to screening visit
8. Alcohol > 21 units/week
9. Caffeinated drink intake > 5units/day
10. Positive on urinary drug screening test or urine nicotine test
11. Positive human immunodeficiency virus (HIV), hepatitis B, hepatitis C, or syphilis test
12. Clinically significant abnormal result of liver function (serum ALT, AST or total bilirubin levels ≥ 1.5 times the upper limit of normal (ULN))
13. Inability to tolerate pH catheter insertion
14. History of symptomatic GERD, erosive esophagitis (EE), duodenal ulcer, gastric ulcer, Barrett's esophagus, or Zollinger-Ellison Syndrome
15. Any other conditions which would have made the subject unsuitable for the study in the opinion of the investigator

Healthy male volunteers