Simultaneous Determination of Bempedoic Acid and Ezetimibe in Rat Plasma Using HPLC–PDA and Its Applications to a Pharmacokinetic Study

Many fixed-dose combinations (FDCs) have recently been used as a potential therapy for patients with hypercholesterolemia and a high risk of cardiovascular disease. In the present study, bempedoic acid and ezetimibe have been simultaneously determined in rat plasma through developing a simple, accurate, precise and rapid HPLC–PDA method. The effective chromatographic separation was performed using an X-bridge C 18 (150 × 4.6 mm, 3.5 µm) with mobile phase comprised of 0.1% TEA in water (pH was adjusted to 2.5 with formic acid) and acetonitrile (40:60, v/v) and was eluted at a flow rate 1 mL min −1 using an isocratic elution mode at 236 nm as detection wavelength. The calibration curves for plasma samples showed linear relationships for bempedoic acid and ezetimibe and the concentrations were found to be in the range of 1.8–36.0 ng mL −1 , 0.1–2.0 ng mL −1 with correlation coefficients (r 2 ) of 0.9997 and 0.9996, respectively. Limits of detection (LOD) and limits of quantification (LOQ) are determined to be 0.6 ng mL −1 , 1.8 ng mL −1 for bempedoic acid and 0.03 ng mL −1 , 0.1 ng mL −1 for ezetimibe in plasma samples, respectively. Recovery studies of bempedoic acid and ezetimibe were obtained in the range of 94.2–98.4% and 94.4–98.8%, respectively. Graphical abstract