Assessment of Gastric pH Changes Induced by Ascorbic Acid Tablets

  • days left to enroll
  • participants needed
  • sponsor
    Indiana University
Updated on 24 April 2022
Accepts healthy volunteers


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.


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.

Condition Hypochlorhydria
Treatment Vitamin C, Omeprazole 20mg
Clinical Study IdentifierNCT04199624
SponsorIndiana University
Last Modified on24 April 2022


Yes No Not Sure

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
Clear my responses

How to participate?

Step 1 Connect with a study center
What happens next?
  • You can expect the study team to contact you via email or phone in the next few days.
  • Sign up as volunteer  to help accelerate the development of new treatments and to get notified about similar trials.

You are contacting

Investigator Avatar

Primary Contact


Additional screening procedures may be conducted by the study team before you can be confirmed eligible to participate.

Learn more

If you are confirmed eligible after full screening, you will be required to understand and sign the informed consent if you decide to enroll in the study. Once enrolled you may be asked to make scheduled visits over a period of time.

Learn more

Complete your scheduled study participation activities and then you are done. You may receive summary of study results if provided by the sponsor.

Learn more

Similar trials to consider


Browse trials for

Not finding what you're looking for?

Every year hundreds of thousands of volunteers step forward to participate in research. Sign up as a volunteer and receive email notifications when clinical trials are posted in the medical category of interest to you.

Sign up as volunteer

user name

Added by • 



Reply by • Private

Lorem ipsum dolor sit amet consectetur, adipisicing elit. Ipsa vel nobis alias. Quae eveniet velit voluptate quo doloribus maxime et dicta in sequi, corporis quod. Ea, dolor eius? Dolore, vel!

  The passcode will expire in None.

No annotations made yet

Add a private note
  • abc Select a piece of text from the left.
  • Add notes visible only to you.
  • Send it to people through a passcode protected link.
Add a private note