Evaluation and Application of ZIC-HILIC Columns Selectivity for Four Angiotensin II Receptor Blockers in Pharmaceutical Formulations

Background: Angiotensin II receptor blockers (ARBs) are helpful medications for treating hypertension and heart failure and have been proposed as a possible alternative to standard angiotensin-converting enzyme inhibitors. Objective: The present article describes and validates sensitive hydrophilic interaction liquid chromatography methods to simultaneously analyse four angiotensin II receptor blockers: valsartan, telmisartan, losartan, and irbesartan. Methods: Numerous chromatographic parameters were studied and optimized in detail. As a mobile phase, the best separation was obtained on two handmade columns (ZIC-S1 and ZIC-S4) using acetonitrile/sodium acetate buffer (40 mM, pH 4.75). The detection of target pharmaceuticals was obtained at 220 nm. Results: The linear ranges of target drugs (valsartan, telmisartan, losartan, and irbesartan) were 0.02-4, 0.06-7, 0.005-6 and 0.08-5 μg/mL on the ZIC-S1 and ZIC-S4 columns, respectively. The suggested methods demonstrated high precision (RSD ≤ 1.15), linearity (r2 ≥ 0.9964), and accuracy (between 98.88 and 101%) with detection and quantitation limits of (0.0021-0.0550 and 0.0063-0.1666 μg/mL, respectively) for all target pharmaceuticals. Conclusion: The suggested methods have been validated and applied to pharmaceutical formulations, indicating that it is suitable for therapeutic drug monitoring of these medications.