HypochlorhydriaPhase 1NCT04199624

Assessment of Gastric pH Changes Induced by Ascorbic Acid Tablets

A Phase 1 study testing Omeprazole 20mg and Vitamin C in people with Hypochlorhydria, run by Indiana University at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

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

Who is it for?: Ages 18 to 30 years, men onlyHealthy volunteers can take part
Conditions the study is for: Hypochlorhydria
What is being tested?: Omeprazole 20mg and Vitamin C
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 11 participants
Where: 1 siteUnited States
Study dates: 1 Oct 2021to 7 Jun 2023
Phase: Phase 1
Are there results?: None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 18 to 30 years
Men only
Healthy volunteers accepted
Adult

Who may be able to join

Healthy, young males age 18-30 years with no prior history of gastrointestinal disease or symptoms.

Who cannot join

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

Trial locations and contacts

1 site in 1 country.

United States1 site

Indiana University School of Medicine
Indianapolis, Indiana, 46202

Other trials in United States

About this study

Read the 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.

Conditions: Hypochlorhydria
Being tested: Omeprazole 20mg, Vitamin C
Medical subject headings: Achlorhydria

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Omeprazole 20mgDrug
Omeprazole twice daily x 5 days
Vitamin CDietary supplement
Ascorbic acid x 1 on day 5

Study groups in NCT04199624
Study group	Role	What they receive
Experimental: omeprazole and ascorbic acid	Experimental	Not described Receives: Drug: Omeprazole 20mg; Dietary Supplement: Vitamin C

What is being measured

The primary outcome is the main question the study is designed to answer.

Change in gastric pH and duration of gastric pH \status
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.
Measured: From time of inpatient appointment to thirteen months after that time point.

Secondary outcomes (1)

Intestinal microbiome profile, intestinal metabolomic profile
To explore the correlation between physiologic responses in gastric pH with features of the intestinal microbiome and microbial metabolites (e.g. metabolome).
Measured: From time of initial stool drop-off to thirteen months after that time point.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

1 Oct 20217 Jun 2023

First posted16 Dec 2019
Study start1 Oct 2021
Primary completion7 Jun 2023
Study completion7 Jun 2023

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Other trials for HypochlorhydriaStudies of the same condition, open and under way.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase 1
Primary purpose: Basic science
Allocation: Not applicable
Intervention model: Single group
Masking: None (open label)
Enrolment: 11 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT04199624
Sponsor's protocol ID: 2006413011
Status last verified: Sep 2025
First submitted: 12 Dec 2019
Last updated: 22 Sep 2025
Results posted: No
Data monitoring committee: Yes
FDA-regulated drug: Yes
FDA-regulated device: No
Individual data sharing: No

Study at a glance

From the registry record, last updated by the sponsor on 22 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Assessment of Gastric pH Changes Induced by Ascorbic Acid Tablets
ClinicalTrials.gov ID: NCT04199624
Acronym / sponsor ID: 2006413011
Conditions: Hypochlorhydria
Phase: Phase 1
Study type: Interventional
Recruitment status: Completed
Enrolment: 11 participants (actual)
Lead sponsor: Indiana UniversityUniversity, hospital or other
Collaborators: Hala Fadda, Butler University
Study start: 1 Oct 2021 (actual)
Primary completion: 7 Jun 2023 (actual)
Study completion: 7 Jun 2023 (actual)
First posted: 16 Dec 2019 (actual)
Results: Not posted in the source record

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Detailed description

Study design

Primary purpose: Basic science
Allocation: Not applicable
Intervention model: Single group
Masking: None (open label)
Number of arms: 1

Arm	Type	Receives
Experimental: omeprazole and ascorbic acid	Experimental	Drug: Omeprazole 20mg, Dietary Supplement: Vitamin C

Who may qualify

Ages: 18 to 30 years
Sex: Male only
Healthy volunteers: Accepted
Age groups: Adult

Key inclusion criteria (1 listed)

Healthy, young males age 18-30 years with no prior history of gastrointestinal disease or symptoms.

Key exclusion criteria (8 listed)

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.

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
Omeprazole 20mgOmeprazole twice daily x 5 days	Drug	Experimental: omeprazole and ascorbic acid
Vitamin CAscorbic acid x 1 on day 5	Dietary supplement	Experimental: omeprazole and ascorbic acid

Primary outcome

Change in gastric pH and duration of gastric pH \status
Time frame: From time of inpatient appointment to thirteen months after that time point.
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.

1 secondary outcome

Intestinal microbiome profile, intestinal metabolomic profile
Time frame: From time of initial stool drop-off to thirteen months after that time point.

Results and safety

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 22 Sep 2025.
Individual participant dataSharing planned: No

Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

The record lists no contact. Use the official record to reach the sponsor.

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A Phase 1 study testing Omeprazole 20mg and Vitamin C in people with Hypochlorhydria, run by Indiana University at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 1 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 22 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change in gastric pH and duration of gastric pH \status (time frame: From time of inpatient appointment to thirteen months after that time point.). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04199624.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Sep 2025.