Improved Gradient Method with Faster Equilibration
The USP Assay Method for Valsartan in combination with Hydrochlorothiazide features a 27 minute gradient with a 13 minute re-equilibration for a total run time of 40 minutes. In this method, the run time was a quarter of the USP method, and the Column equilibrates much faster when gradients are used. This demonstrates a substantial time and solvent savings for the analytical laboratory.
Five Chromatograms are overlaid below which shows the Robustness and Precision of this Method.
1. Hydrochlorothiazide (HCT)
Column: Cogent Bidentate C18™, 4μm, 100Å
Catalog No.: 40018-75P
Dimensions: 4.6 x 75mm
—A: DI Water / 0.1% Trifluoroacetic Acid (TFA)
—B: Acetonitrile / 0.1% Trifluoroacetic Acid (TFA)
Post Time: 1 minute
Injection vol.: 10μL
Flow rate: 1.0ml / minute
Detection: UV @ 265nm
—Stock Solution: A Diovan® HCT brand tablet containing 160mg Valsartan and 25 mg Hydrochlorothiazide was ground and added to a 50 mL volumetric flask. The flask was diluted to mark with 50:50 Solvent A / Solvent B mixture and sonicated. A portion was then filtered with a 0.45μm Nylon Syringe Filter AQ™ Brand (MicroSolv Tech Corp.).
––Working Solution: 100μL of the stock solution was diluted with 900μL of a 50:50 Solvent A / Solvent B mixture.
t0: 1 minute
|Comparison of This Method and the USP Method|
|Bidentate C18||Ordinary C18|
|Total Run Time||10 Minutes||40 Minutes|
|Column Volume Equilibration||1 Column||10 Columns|
|Solvent Usage per Run||10ml||40ml|
No 150 Valsartan and Hydrochlorothiazide Analyzed with HPLC pdf 0.5 Mb Download File