Assessment of Gastric pH Changes Induced by Ascorbic Acid Tablets

Indiana University (Other)
Overall Status
Recruiting ID
Hala Fadda (Other), Butler University (Other)

Study Details

Study Description

Brief Summary

This study evaluates the use of ascorbic acid, vitamin C, to temporary reduce gastric pH in individuals with omeprazole induced hypochlorhydia. All participants will receive ascorbic acid tablets to measure the change in gastric pH.

Condition or Disease Intervention/Treatment Phase
  • Drug: Omeprazole 20mg
  • Dietary Supplement: Vitamin C
Phase 1

Detailed Description

Elevation of gastric pH in patients with hypochlorhydria can reduce the solubility of weakly basic drugs. This may lead to poor and unpredictable systemic exposure for poorly soluble drugs. For example, extent of absorption of the kinase inhibitors, dasatinib (Sprycel) and erlotinib (Tarceva), is reduced by up to 61% and 46% respectively in patients on acid-reducing agents (ARAs). This pilot study is to evaluate the use of ascorbic acid, vitamin C, to temporary reduce gastric pH in individuals with omeprazole induced hypochlorhdyria. Using pH/impedance testing, we are seeking to determine the magnitude and duration of pH change upon administration of 1000 mg of ascorbic acid in healthy subjects with proton-pump inhibitor induced hypochlorhydria. The results from this study will be used to evaluate the use of ascorbic acid as a drug-drug interaction mitigation strategy.

Study Design

Study Type:
Anticipated Enrollment :
10 participants
Intervention Model:
Single Group Assignment
None (Open Label)
Primary Purpose:
Official Title:
Assessment of Gastric pH Changes Induced by Ascorbic Acid Tablets
Actual Study Start Date :
Oct 1, 2021
Anticipated Primary Completion Date :
Dec 15, 2022
Anticipated Study Completion Date :
Dec 15, 2022

Arms and Interventions

Arm Intervention/Treatment
Experimental: Experimental: omeprazole and ascorbic acid

Drug: Omeprazole 20mg
Omeprazole twice daily x 5 days

Dietary Supplement: Vitamin C
Ascorbic acid x 1 on day 5

Outcome Measures

Primary Outcome Measures

  1. Change in gastric pH and duration of gastric pH \status [Five hours]

    Gastric pH measurements will be continuously monitored throughout the study using a catheter-based pH monitoring system. Gastric pH versus time data will be collected for five hours.

Eligibility Criteria


Ages Eligible for Study:
18 Years to 30 Years
Sexes Eligible for Study:
Accepts Healthy Volunteers:
Inclusion Criteria:
  • Healthy, young males age 18-30 years with no prior history of gastrointestinal disease or symptoms.
Exclusion Criteria:
  • Hypochlorhydria (baseline use antacids, antisecretory medications, or surface agents including proton-pump inhibitors, H2 blockers, or sucralfate).

  • Current or previous history of gastrointestinal disease including gastroesophageal reflux disease, Barrett's esophagus, peptic ulcer disease, dyspepsia, gastroparesis, bacterial overgrowth, microscopic colitis, gastric intestinal metaplasia or metaplastic atrophic gastritis, gastric neuroendocrine tumors, helicobacter pylori infection, inflammatory bowel disease (Crohn's disease or ulcerative colitis), celiac disease, visceral cancer, chronic infectious disease, immunodeficiency, uncontrolled thyroid disease, history of liver disease).

  • History of gastric bypass or other abdominal surgeries excluding cholecystectomy or appendectomy > 6 months prior to study initiation.

  • Radiation therapy to the abdomen.

  • Pregnant females.

  • Ingestion of any prescription, over-the-counter, or herbal medications which may affect study interpretation.

  • Currently a smoker

  • Antibiotic use within the last 3 months

Contacts and Locations


Site City State Country Postal Code
1 Indiana University School of Medicine Indianapolis Indiana United States 46202

Sponsors and Collaborators

  • Indiana University
  • Hala Fadda
  • Butler University


None specified.

Study Documents (Full-Text)

None provided.

More Information


None provided.
Responsible Party:
Andrea Shin, Assistant Professor, Indiana University Identifier:
Other Study ID Numbers:
  • 1911069261
First Posted:
Dec 16, 2019
Last Update Posted:
Apr 6, 2022
Last Verified:
Mar 1, 2022
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD:
Studies a U.S. FDA-regulated Drug Product:
Studies a U.S. FDA-regulated Device Product:
Product Manufactured in and Exported from the U.S.:
Additional relevant MeSH terms:

Study Results

No Results Posted as of Apr 6, 2022