FOR PHARMA & CROs

Gastric pH is a drug development variable. Measure it directly.

For weakly basic compounds and BCS Class II and IV molecules, gastric pH governs solubility, dissolution, and bioavailability. For acid-suppressing drugs, intragastric pH is the pharmacodynamic effect itself. The Heidelberg pH Capsule System measures intragastric pH in real time in conscious human subjects, supporting clinical pharmacology programs where gastric acidity is the independent or the dependent variable.

An endpoint you can measure.

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Sample Tracing

Bicarbonate challenge~45–90 min

Acid-Reducing Agent DDI

Characterize the pH-dependent interaction the agency asks about.

FDA's guidance for industry on evaluating gastric pH-dependent drug interactions with acid-reducing agents asks sponsors to assess early whether an investigational drug is susceptible to gastric-pH-mediated DDIs, because acid-reducing agents can lower the bioavailability of weak-base drugs and raise exposure of weak-acid drugs.

Real time intragastric pH provides direct verification of the acid state under which a pharmacokinetic interaction is being characterized.

pH-Dependent Exposure

Acid-reducing agents raise gastric pHWeak bases ↓ · weak acids ↑

APPLICATIONS

Where gastric pH enters the program.

Bioavailability & PK

When the molecule is a weak base.

Many oral oncology tyrosine kinase inhibitors are weak bases with pH-dependent solubility, and concomitant acid-reducing agents reduce their exposure — across agents including dasatinib, erlotinib, and nilotinib.

Reviewed in ESMO Open 2023.

PPI & P-CAB Pharmacology

Intragastric pH as the endpoint.

Onset, magnitude, and duration of acid suppression; percent time pH exceeds a threshold; nocturnal acid breakthrough. Vonoprazan raises 24-hour pH > 4 holding-time ratios to 83 percent by day 7.

Echizen, Clin Pharmacokinet 2016.

Gastric-Retentive Formulations

Characterize the environment.

Gastric pH and residence behavior characterization for gastric-retentive and pH-dependent dosage forms in fed and fasted states.

Mojaverian et al., Gastroenterology 1985.

Special Populations

Altered anatomy, altered pH.

Post-bariatric gastric pH rises 3 to 4 units; aging and atrophic gastritis shift baseline acidity — populations warranting direct pH characterization.

Porat / Azran et al., 2021.

ARA-DDI Verification

Confirm the acid state.

Direct measurement of the gastric pH under which an acid-reducing-agent interaction is characterized, per FDA guidance.

Multi-Site Trials

Standardized across sites.

A reproducible bicarbonate challenge methodology and explicit endpoints travel across clinical pharmacology units.

HOW IT WORKS

One capsule, one hour, a quantitative tracing.

CALIBRATE

Two-point calibration at pH 1.0 and pH 7.0 against reference buffers.

ADMINISTER

The subject swallows the tethered capsule. Record fasting baseline pH, then deliver sequential sodium bicarbonate challenges.

MEASURE

Time the return to baseline acidity after each challenge. Reacidification interval, pattern, and how strongly the stomach restores its acidity, read directly from the tracing..

See the full protocol →

ENGAGEMENT

How sponsors and CROs work with us.

Equipment and capsule supply for clinical pharmacology units, protocol and calibration support, and methodological consultation for pH-dependent absorption, ARA-DDI, and antisecretory PD programs.

PER-STUDY SUPPLY

System and single-use capsules provided for the study, with calibration standards.

ENDPOINT DESIGN

Support defining intragastric pH endpoints and the challenge protocol for your program.

CLINICAL PHARMACOLOGY UNITS

Deployable in CPU and early-phase settings for PK and PD studies.

METHODOLOGICAL CONSULTATION

Input on acid-state verification, calibration, and data interpretation.

Get in touch

Scope a study.

Tell us your program and endpoint of interest. We will follow up.

Or email us directly at info@heidelbergmed.com

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The Heidelberg pH Capsule is a Class I, 510(k)-exempt, preamendments device, classified under 21 CFR §876.1400. Registration of an establishment or listing of a device does not denote FDA approval, clearance, or endorsement.