s Development and Validation of a Reliable LC-MS/MS Method for Simultaneous Quantification of Hydrochlorothiazide in the Presence of Different Co-formulated Anti-hypertensive Medications in Biological Matrix

Background: Thiazide diuretics are listed as one of the first-line antihypertensive treatment agents. Hydrochlorothiazide is mainly formulated with many antihypertensive agents as combined pill therapy. Objective: In this study, a new, simple, rapid and sensitive LC-MS/MS assay was developed, optimized and validated for the simultaneous quantification of commonly prescribed cardiovascular combined medications that are used for hypertension management, including Hydrochlorothiazide (HCT) in the presence of irbesartan (IRB), candesartan (CAN) and bisoprolol (BISO) in human plasma. Methods: RP-HPLC separation of analytes and internal standard (atorvastatin) was performed on Zorbax Eclipse XDB-C18 (4.6×50 mm 5-Micron) using acetonitrile: (0.05%) formic acid (80:20), as an eluting system with a run time of less than 5.0 min. Results: Validation was carried out according to FDA guidelines for bioanalytical method. The recoveries were higher than 84.30%, the accuracy was within 86.82–110.17 % and the RSD was below 10% for all the studied compounds. Conclusion: The suggested method is highly appropriate for routine assays of the studied combination therapy in view of the lower LLOQ, simple extraction process, and short run time. The method can be further investigated and used for pharmacokinetics studies of the studied different antihypertensive combinations.