Ion-pair LC method for simultaneous determination of aliskiren hemifumarate, amlodipine besylate and hydrochlorothiazide in pharmaceuticals

A rapid and precise LC method was developed for the simultaneous determination of aliskiren hemifumarate (ALS), amlodipine besylate (AML) and hydrochlorothiazide (HCZ) using acetonitrile:25 mM octane sulfonic acid sodium salt monohydrate in water (60:40 v/v) as the mobile phase. The flow rate was maintained at 1.2 mL min^-1 on a stationary phase composed of Supelco, Discovery® HS (C18) column (25 cm x 4.6 mm, 5 μm). Isocratic elution was applied throughout the analysis. Detection was carried out at λ_max (232 nm) at ambient temperature. The method was validated according to ICH guidelines. Linearity, accuracy and precision were satisfactory over the concentration ranges of 32-320, 2-44 and 4-64 μg mL^-1 for ALS, AML and HCZ, respectively. LOD and LOQ were estimated and found to be 0.855 and 2.951 μg mL^-1, respectively, for ALS, 0.061 and 0.202 μg mL^-1, respectively, for AML as well as 0.052 and 0.174 μg mL^-1, respectively, for HCZ. The method was successfully applied for the determination of the three drugs in their co-formulated tablets. The results were compared statistically with reference methods and no significant difference was found. The developed method is specific and accurate for the quality control and routine analysis of the cited drugs in pharmaceutical preparations.