Comparison of the Effect of Rabeprazole 50 mg DDR Capsules and 20 mg Enteric-coated Tablets

Inclusion Criteria: * Diagnosis of GERD with symptoms (i.e. regurgitation, pyrosis) at least 1 or more episodes a week. * Age ≥ 18 years and \<65 years * Helicobacter pylori (an infection) negative * Have a body mass index (BMI) between 18 and 33 kg/m² * pH\>4 gastric exposure \<25% on a 24-hour dual pH channel monitoring study performed prior to screening (normal intragastric pH +2SD) * Pathologic intraesophageal acidity exposure (DeMeester score \>14.75 and/or \>4% of pH\<4 (at least 21 hours measured) Exclusion Criteria: * Patiets with Barrett's stricture, gastric outlet obstruction, malignancy, gastrointestinal system bleeding or any other upper gastrointestinal system pathology. * Patients whose Hiatus hernia is \> 3 cm. * Patients with uncontrolled or insulin dependent diabetes mellitus, symptomatic gallbladder stone, active or unhealed stomach or duodenum ulcer, Zollinger-Ellison syndrome, primary esophagus motility disorder, pancreatitis, inflammatory bowel disease, severe lung disease, chronic liver disease, uncontrolled kidney impairment, cancer (except skin cancer except melanoma), cerebrovascular disease, epilepsy. * Patients with history of heart failure, ventricular tachycardia, ventricular fibrillation, cardiac arrest, Torsades de pointes, bradycardia, sinus node dysfunction, heart attack, long QTc (\>450 ms for male, \>470 ms for female patients). * Patients taken PPIs or H2-blockers within 7 days and prokinetic drugs within 3 days before entering the study. * Patients with major psychiatric disease. * Alcoholism and drug use. * Patients with pathologic laboratory tests; hemogram, sedimentation, CRP, thyroid functions tests, liver enzymes. * Malabsorbtion. * Immunosuppressive patients. * Patients taken cortisone. * Patients taken other drugs that prolong QT interval. * Patients taken drugs that need gastric acid for optimal absorption; ketoconazole, iron salts, digoxin, ampicillin esters, anticoagulants, antineoplastic agents, prostaglandin analogues, sukralfat. * Pregnancy or breast-feeding. * Patients taken drugs that may affect gastrointestinal system motility or acid release. * History of abdominal surgery (hysterectomy, abdominal hernia repair, caesarean cases may be included; cholecystectomy have to be excluded). * Patients taken NSAII drugs (paracetemol may be used up to 2 gr/day). * Patients taken antidepressants. * Hypersensitivty to study drugs. * Known allergy to peanut and soy.