The goal of this randomized, double-blind, single-center clinical trial is to learn if medical devices work to decrease nocturnal symptoms of GERD gastroesophageal reflux disease in adults' patients and improve sleeping time, quality of sleep and quality of life of patients with nocturnal GERD symptoms. It will also teach us about safety, tolerability and improvement of patient's quality of life during and after taking medical device. The main questions it aims to answer are:

• Does medical device relieve reflux symptoms during night sleep?
• Does medical device improve the quality of sleep and quality of life life of patients with GERD symptoms? Researchers will compare medical device to a placebo (a look-alike substance that contains no drug) to see if medical device works in nocturnal GERD gastroesophageal reflux disease.

Participants will:

• Take medical device or a placebo every day just before sleeping (1 times a day) for 14 days
• Visit the clinic 2 times during 14 days of this study for checkups and tests
• Keep a diary of their symptoms and the number of times they use a medical device
• Fill out the form to collect all necessary data. Medical device or placebo will be prepared in same looking sachets of 10 ml liquid. Medical device or placebo will be administered orally, at a dose of 10 ml one time daily just before bedtime for 14 days. The liquid should be drunk slowly, in small sips direct from the sachets.

This medical device was developed as a modern therapeutic alternative, offering rapid symptom relief and long-term protective effects on the esophageal mucosa. The introduction of medical device aims to expand the available therapeutic options for patients suffering from nocturnal GERD symptoms and to support physicians in selecting optimal therapy. Thanks to its innovative formula, medical device can avoid the rising the symptoms, provide improved well-being , improved lenght and quality of sleep , quality of life and reduce the frequency of acute medication use.

Inclusion Criteria:

1. Diagnosis of gastroesophageal reflux disease based on the presence of typical symptoms of heartburn and/or regurgitation at least 6 months before the screening visit, confirmed by the investigator.

2. Erosive reflux disease (ERD), Barrett's esophagus, and other esophageal abnormalities confirmed by gastroscopy within the last 6 months by the investigator based on medical records.

3. Use of proton pump inhibitors in a single morning dose for at least two months prior to study entry, with an inadequate response to these medications for nocturnal symptoms of gastrointestinal reflux, and with at least moderate sleep quality disturbances, as defined by the PSQI (Pittsburgh Sleep Quality Index) score of 5-10 points - moderate sleep disturbances. 4. Not using the following medications within the month prior to the screening visit: H2 blockers, prokinetics (itopride, prucalopride), GLP1/GIP analogues, antibiotics, baclofen, tricyclic antidepressants, serotonin and/or norepinephrine reuptake inhibitors, and/or the following medications within the week prior to the screening visit: sucralfate, antacids, and esophageal protective agents. 5. Severity of gastroesophageal reflux symptoms that reduce the patient's quality of life, as subjectively confirmed by the patient. 6. Age ≥18 years of life at the time of the screening visit. 7. At the screening visit, women of childbearing potential must not be pregnant (confirmed by a urine pregnancy test) and must not be breastfeeding, or must be of non-reproductive potential (surgically sterilized, physiologically incapable of conceiving, or at least one year postmenopausal, i.e., amenorrheic for 12 consecutive months). 8. Women of childbearing potential who have a male partner of fertile potential must use a highly effective method of contraception from the screening visit until 18 weeks after the last dose of the investigational drug. 9. Men who have sex with women of childbearing potential must agree to use barrier contraceptive methods (condoms) or abstain from sexual intercourse throughout the study, beginning at the screening visit and for at least 7 days after the last dose of the investigational medical device. 10. Ability to participate in all aspects of this clinical trial. 11. A male or female patient who is able to voluntarily give informed consent.

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   Exclusion Criteria:

1. Women who have started lactation or have a positive urine test confirming pregnancy during the study enrollment visit.2. Introduction of significant changes in diet and lifestyle during the study.3. Presence of warning signs during the study enrollment visit: dysphagia or odynophagia, unintentional weight loss of more than 5% of initial weight, symptoms of gastrointestinal bleeding, anemia, upper abdominal tumor, and persistent vomiting for 7-10 days.4. Planned use during the study: antibiotics, pro-/pre-/synbiotics, short-chain fatty acids, proton pump inhibitors, H2 blockers, prokinetics (itopride, prucalopride), GLP1/GIP analogues, antibiotics, baclofen, tricyclic antidepressants, serotonin and/or norepinephrine reuptake inhibitors, and one week before the start of the study: sucralfate, antacids, and preparations protecting the esophageal mucosa.5. Diagnosis of a serious illness (e.g., cancer). 6. : Planned hospitalization for any reason or diagnosis of any serious concomitant disease which, in the opinion of the investigator, is a contraindication to participation in the study or may compromise the safety of the patient. Translated with DeepL.com (free version) 7. Current or recent (within one year prior to randomization) history of alcohol dependence or psychoactive substance abuse.8. Active psychiatric problems that, in the investigator's opinion, may interfere with compliance with study procedures.9. Presence of unstable or uncontrolled cardiovascular disorders, moderate or severe heart failure (NYHA class III or IV), any pulmonary, hepatic, renal, gastrointestinal, genitourinary, hematopoietic, coagulation, immunological, endocrine/metabolic disorders, or other medical disorders that, in the opinion of the investigator, could affect the results of the study or compromise the safety of the patient.10. Any person who:a. Is an employee of the study site, investigator, study organization, or Sponsor.b. Is a first-degree relative of an employee of the study site, investigator, CRO, or Sponsor.c. Is unable to attend all study visits or comply with study procedures.Translated with DeepL.com (free version)

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Individual participant data will not be made publicly available due to privacy considerations and applicable data protection regulations. Aggregated and anonymized results will be reported in scientific publications. Data may be available from the corresponding author upon reasonable request, subject to institutional approval and data sharing agreements.

Non applicable