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

Executive Summary: 3-(quinolin-4-ylmethylamino)-N-[4-(trifluoromethoxy)phenyl]thiophene-2-carboxamide (SKU: A2845) is a high-purity H+,K+-ATPase inhibitor developed for research in gastric acid-related disorders, demonstrating potent activity with an IC50 of 5.8 μM against the ATPase enzyme and 0.16 μM for inhibiting histamine-induced acid formation (APExBIO, product page). It is supplied as a solid, is insoluble in water and ethanol, but dissolves at ≥17.27 mg/mL in DMSO, supporting robust assay design. The compound's antiulcer and antisecretory properties are validated by HPLC and NMR at 98% purity, enabling reproducible antiulcer activity studies (https://doi.org/10.1111/ejn.70227). This article details mechanistic rationale, use cases, benchmarks, and practical limits for research workflows.

Biological Rationale

The gastric H+,K+-ATPase proton pump is the final effector in the acidification of gastric juice. Dysregulated acid secretion is linked to peptic ulcer disease and gastroesophageal reflux (GORD). Pharmacological inhibition of H+,K+-ATPase is the central therapeutic approach for acid-related disorders, enabling the study of gastric mucosal protection and ulcer healing mechanisms. Compounds like 3-(quinolin-4-ylmethylamino)-N-[4-(trifluoromethoxy)phenyl]thiophene-2-carboxamide provide precise tools for dissecting proton pump inhibition pathways, supporting both in vitro and in vivo models. Experimental modulation of acid secretion also informs research into gut–brain and gut–liver axis disorders, as recent studies highlight the interplay between gastric acid, microbiota, and systemic inflammation (Kong et al., 2025).

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

3-(quinolin-4-ylmethylamino)-N-[4-(trifluoromethoxy)phenyl]thiophene-2-carboxamide is a small molecule inhibitor that selectively targets the H+,K+-ATPase enzyme located in gastric parietal cells. By binding the enzyme, it prevents the final step of acid secretion into the stomach lumen. The compound demonstrates an IC50 of 5.8 μM for H+,K+-ATPase inhibition under standard biochemical assay conditions (pH 7.4, 25°C), and a much lower IC50 (0.16 μM) for histamine-induced acid formation in cellular models. This dual activity allows for precise modulation of acid output and characterization of downstream effects on mucosal integrity. The mechanism is non-covalent and reversible under most experimental conditions, differentiating it from covalent proton pump inhibitors like omeprazole. The compound’s structure–activity relationship confers high specificity, minimizing off-target effects in complex biological systems (see also workflow optimization article).

Evidence & Benchmarks

• Inhibits H+,K+-ATPase with an IC50 of 5.8 μM in purified enzyme assays (APExBIO, data sheet).
• Blocks histamine-induced acid secretion in gastric cell models with an IC50 of 0.16 μM (Kong et al., 2025).
• Antiulcer efficacy established in preclinical gastric ulcer models, demonstrating dose-dependent protection of mucosal tissue (protocols and benchmarks).
• Purity verified at ≥98% by HPLC and NMR, ensuring consistency for cell-based and animal studies (APExBIO, QC data).
• Solubility profile: Insoluble in water and ethanol; dissolves at ≥17.27 mg/mL in DMSO; optimal for high-throughput screening (compound profile).
• Stable as a solid at -20°C for long-term storage; not recommended for prolonged solution storage (APExBIO, handling guide).

Applications, Limits & Misconceptions

This compound is used as a research tool in:

• Dissecting the proton pump inhibition pathway in gastric acid secretion research (more mechanistic detail here—this article expands with new IC50 data).
• Validating antiulcer agents in peptic ulcer disease animal models (workflow troubleshooting here—this piece adds purity and storage best practices).
• Translational studies exploring the gut–brain axis, neuroinflammation, and the impact of gastric acid modulation (see translational neuroinflammation context; this article updates with focused application boundaries).

Common Pitfalls or Misconceptions

• This compound is not intended for diagnostic or therapeutic use in humans; for research use only.
• Not suitable for studies requiring water- or ethanol-soluble agents without DMSO-based delivery systems.
• Long-term storage in solution (especially DMSO) can result in degradation or loss of potency—prefer solid-state storage at -20°C.
• Does not covalently modify H+,K+-ATPase; effects are reversible and may not fully mimic the pharmacokinetics of clinical PPIs like omeprazole.
• Off-target activity profile not fully characterized in non-gastric tissues; exercise caution in extrapolating findings outside gastric models.

Workflow Integration & Parameters

The recommended workflow for using 3-(quinolin-4-ylmethylamino)-N-[4-(trifluoromethoxy)phenyl]thiophene-2-carboxamide (A2845) includes:

• Preparation: Dissolve compound in DMSO to make stock solution (≥17.27 mg/mL); dilute into assay buffer just prior to use.
• Concentration Ranges: For enzyme assays, use 1–10 μM; for cellular models, 0.05–1 μM is typical for robust inhibition.
• Controls: Include vehicle (DMSO) and reference PPI controls for benchmarking.
• Storage: Solid at -20°C; avoid repeated freeze–thaw of stock solutions.
• Assay Compatibility: Compatible with H+,K+-ATPase activity assays, acid secretion quantification, and cell viability/cytotoxicity endpoints (scenario-driven solutions here, expanded here with new purity benchmarks).

Conclusion & Outlook

3-(quinolin-4-ylmethylamino)-N-[4-(trifluoromethoxy)phenyl]thiophene-2-carboxamide from APExBIO (SKU: A2845) is a validated, high-purity H+,K+-ATPase inhibitor designed for research in gastric acid secretion and antiulcer activity. Its defined IC50 values, robust solubility in DMSO, and stringent quality control make it an optimal choice for peptic ulcer disease models, the study of the proton pump inhibition pathway, and exploratory work in the gut–brain axis. Future directions include expanded profiling of off-target effects, integration into multi-omics workflows, and use in translational neuroinflammation research. For detailed product specifications, visit the APExBIO A2845 product page.