3-(quinolin-4-ylmethylamino)-N-[4-(trifluoromethoxy)phenyl]thiophene-2-carboxamide: A Benchmark H+,K+-ATPase Inhibitor for Gastric Acid Secretion Research

Executive Summary: 3-(quinolin-4-ylmethylamino)-N-[4-(trifluoromethoxy)phenyl]thiophene-2-carboxamide (A2845) is a potent and selective H+,K+-ATPase inhibitor with a reported IC50 of 5.8 μM for enzyme inhibition and 0.16 μM for histamine-induced acid formation, demonstrating robust antiulcer activity under controlled conditions (APExBIO). The compound is insoluble in water and ethanol but dissolves at ≥17.27 mg/mL in DMSO; it is supplied at ≥98% purity (HPLC/NMR) and is stable at -20°C. A2845 enables reproducible, high-fidelity studies of gastric acid secretion and related pathways (DPPIV). It is not recommended for diagnostic or clinical use, ensuring exclusive application in controlled research settings.

Biological Rationale

Gastric acid secretion is mediated by the gastric H+,K+-ATPase, or proton pump, located in the parietal cell membrane. Overactivity of this pump contributes to disorders such as peptic ulcer disease, GERD, and Zollinger-Ellison syndrome. Selective inhibition of H+,K+-ATPase is a validated strategy for suppressing gastric acid output and mitigating mucosal injury (Kong et al., 2025). Animal models of acid secretion and ulceration rely on precise, reproducible blockade of this pathway to benchmark candidate antiulcer agents and dissect signaling mechanisms (DPPIV (2023)). 3-(quinolin-4-ylmethylamino)-N-[4-(trifluoromethoxy)phenyl]thiophene-2-carboxamide provides a robust tool for these applications, offering a defined pharmacological profile for mechanistic interrogation.

Mechanism of Action of 3-(quinolin-4-ylmethylamino)-N-[4-(trifluoromethoxy)phenyl]thiophene-2-carboxamide

A2845 acts as a competitive inhibitor of the H+,K+-ATPase enzyme. It binds to the catalytic pocket of the proton pump, preventing ATP hydrolysis and subsequent translocation of H+ and K+ ions across the gastric parietal cell membrane. This inhibition suppresses the final common step in acid secretion, regardless of upstream stimulatory pathways (e.g., histamine, acetylcholine, gastrin). The compound's IC50 for H+,K+-ATPase inhibition is 5.8 μM; for histamine-induced acid formation, it is 0.16 μM, reflecting high potency in functional models (APExBIO). Unlike classic irreversible inhibitors (e.g., omeprazole), A2845 does not require acidic activation, facilitating direct mode-of-action studies in isolated systems (atpsolution.com).

Evidence & Benchmarks

• IC50 for H+,K+-ATPase enzymatic inhibition: 5.8 μM under standard in vitro ATPase assay conditions (pH 7.4, 37°C, 30 min) (APExBIO).
• IC50 for inhibition of histamine-induced acid formation: 0.16 μM in isolated gastric mucosa preparations (DPPIV).
• Purity: ≥98% as verified by HPLC and NMR analysis, ensuring minimal off-target effects (APExBIO).
• Solubility: Insoluble in water and ethanol; solubility in DMSO is ≥17.27 mg/mL at room temperature, enabling high-concentration stock solutions for in vitro use (APExBIO).
• Demonstrated efficacy in antiulcer animal models; robust suppression of acid output and mucosal damage in rat peptic ulcer models (Kong et al., 2025).

Applications, Limits & Misconceptions

A2845 is designed for use in gastric acid secretion research, antiulcer activity studies, and mechanistic dissection of the proton pump inhibition pathway. It is suitable for in vitro biochemical assays, ex vivo tissue studies, and in vivo animal models of peptic ulcer disease. The compound enables protocol standardization and comparative benchmarking in preclinical workflows (atpsolution.com - This article extends previous coverage by detailing practical troubleshooting and advanced integration).

However, A2845 is not intended for diagnostic, therapeutic, or clinical applications in humans. It is not a direct surrogate for clinically approved proton pump inhibitors due to its research-only regulatory status and distinct chemical structure. Misapplication in long-term solution storage can result in compound degradation. The reagent should not be used in non-acidic or non-proton pump-dependent models.

Common Pitfalls or Misconceptions

• Not for clinical or diagnostic use: The compound lacks regulatory approval for patient care or human diagnostics.
• Limited solubility in aqueous buffers: Attempting to dissolve A2845 in water or ethanol leads to precipitation; use DMSO as the solvent.
• Stability concerns in solution: Long-term storage in DMSO or other solvents reduces potency; prepare fresh stocks for each experiment.
• Not a covalent inhibitor: Unlike omeprazole, A2845 does not form irreversible bonds and is not activated by acid-catalyzed rearrangement.
• Species differences: Potency and selectivity may vary across animal models; always verify assay conditions.

Workflow Integration & Parameters

For in vitro assays, dissolve A2845 at ≥17.27 mg/mL in DMSO; further dilute into assay buffer to achieve target concentrations (e.g., 0.1–10 μM). Store powder at -20°C, protected from light and moisture. Avoid repeated freeze-thaw cycles. For animal studies, formulate immediately prior to use and ensure vehicle compatibility. Purity and identity are confirmed by HPLC and NMR, supporting reproducible results. For advanced protocol design, the article "Optimizing Gastric Acid Secretion Research with 3-(quinolin-4-ylmethylamino)..." offers stepwise integration guidance—this page provides an updated stability and benchmarking profile.

Conclusion & Outlook

3-(quinolin-4-ylmethylamino)-N-[4-(trifluoromethoxy)phenyl]thiophene-2-carboxamide (A2845) from APExBIO sets a new standard for precise, reproducible research on gastric acid secretion and antiulcer mechanisms. Its well-characterized potency, selectivity, and solubility support robust experimental designs in peptic ulcer disease models and proton pump pathway studies. Ongoing research into the gut-brain axis and neuroinflammatory connections may benefit from such high-fidelity research tools (acridine-orange.com – This article expands on the role of proton pump inhibitors in gut-brain and neuroinflammation studies, building on the mechanism-focused content here). Future directions include leveraging A2845 in translational models and in systems-level analyses of acid secretion and related disorders.