Development of a simple and accurate RP-HPLC-UV for determination of choleretic drug alibendol in human plasma and its application for a pharmacokinetic study

An accurate and selective high-performance liquid chromatography with ultraviolet detector (HPLC-UV) method was developed for quantification of alibendol in human plasma. The sample was prepared by one-step liquid-liquid extraction (LLE) using ethyl acetate from plasma. The chromatographic retention times of alibendol and carvedilol (the internal standard; IS) were 4.3 and 3.5 min, respectively, on a reverse phase C₁₈ CAPCELL PAK (250 mm 4.6 mm I.D., 5 μm) column. The isocratic mobile phase consisted of acetonitrile-10 mM sodium phosphate (45:55, v/v; adjusted to pH 3.0 with phosphoric acid). The lower limit of quantitation (LLOQ) was 0.3 μg/mL and no interferences were detected in chromatograms. The developed HPLC method was validated by evaluating its inter- and intra-day precisions and accuracies for a linear concentration range of 0.3 and 20.0 μg/mL. Stability testing showed that alibendol was stable in human plasma during sample processing and storage. The proposed method was successfully applied to the pharmacokinetic study of the single-dose oral administration of 100 mg alibendol tablet in healthy Korean male volunteers. The Cmax, T_1/2 and AUC_0-t of alibendol were 5.82 ± 1.40 μg/mL, 1.47 ± 0.43 h, 10.62 ± 2.40 μg·h/mL, respectively.