High Performance Liquid Chromatography (HPLC) with ultraviolet/visible (UV/Vis) or diode array detection (DAD) is routinely used for drug quantification in R&D all around the world. However, it may lack the sensitivity required for bioanalytical studies. On the other hand, HPLC with fluorescence detection (FLD) is a cost-effective alternative that significantly increases drug signal, allowing the detection of compounds at very low concentrations. Pitavastatin is a lipid-lowering drug that contains the structure of quinoline, a highly fluorescent molecule. Recently, it has gained interest due to its promising antitumoral activity over different types of cancer [2].
Bearing this in mind, an HPLC-FLD method was herein developed and validated for the quantification of pitavastatin in human plasma, according to the ICH M10 guideline [1]. Overall, a signal gain of 54-70 times was achieved when using fluorescence vs UV detection. Sample preparation included a one-step protein precipitation with acetonitrile, followed by centrifugation and filtration prior to injection. Pitavastatin was separated from endogenous matrix interferents using a C18 column and applying a gradient elution. Atorvastatin was used as internal standard. Accordingly, the method was shown to be selective, specific, and sensitive, with the lower limit of quantification of 3 ng/mL and a complete absolute and relative recoveries above 94 %. The method was linear over the concentration range of 3 – 900 ng/mL (r2 > 0.998), accurate (bias < 7.15 %) and precise (RSD < 9.63 %). This method allows the therapeutic monitoring of patients treated with pitavastatin but can also support novel clinical studies of this drug in human plasma.
[1] ICH – International Council for Harmonisation (2022). ICH Guideline M10 on Bioanalytical Method Validation and Study Sample Analysis, 1-45.
[2] Jiang, W., Hu, J. W., He, X. R., Jin, W. L., & He, X. Y. (2021). Statins: a repurposed drug to fight cancer. Journal of Experimental & Clinical Cancer Research, 40, 1-33.
