LC-MS/MS Method Development and Validation for Clinical Pharmacokinetics and Therapeutic Drug Monitoring of Potassium-Competitive Acid Blocker Vonoprazan-Based Triple Therapy for H. pylori in Human Plasma

Background: A novel triple therapy regimen for Helicobacter pylori eradication, recently approved by the U.S. FDA, comprises vonoprazan (VPN), a potassium-competitive acid blocker, in combination with amoxicillin (AMX) and clarithromycin (CMN). This study presents the development and full validation of a rapid, selective, and sensitive LC-MS/MS method for the simultaneous quantification of these three drugs in spiked human plasma. Methods: Sample preparation was performed using a simple and efficient liquid–liquid extraction (LLE) technique. Chromatographic separation was achieved within 5 min using a Phenomenex Kinetex C18 column (100 × 4.6 mm, 2.6 µm) and a gradient elution system consisting of 0.1% formic acid in water and acetonitrile. Moreover, diazepam was used as an internal standard. The mass spectrometric detection was conducted in multiple reaction monitoring (MRM) mode using positive electrospray ionization. Results: The method exhibited excellent linearity over the investigated concentration ranges (2, 5, 10, 20, 50, and 100 ng/mL for amoxicillin and clarithromycin and 5, 10, 20, 30, 50, and 100 ng/mL for vonoprazan). Intra- and inter-day precision and accuracy values met FDA bioanalytical method validation guidelines, with relative standard deviations and relative errors below 15%. Mean absolute recoveries were above 93% for all analytes. Conclusions: The developed method was fully validated, rapid, selective, and sensitive LC-MS/MS and was assessed using the AGREE tool as a greenness assessment approach, confirming its environmental friendliness and alignment with green analytical chemistry principles.