Determination of inositol hexanicotinate in rat plasma by high performance liquid chromatography with UV detection

A HPLC method with UV detection at 262 nm was developed to analyze inositol hexanicotinate in rat plasma. Plasma samples were extracted with an equal volume of acetonitrile, followed by dilution with mobile phase buffer (5 mM phosphate buffer, pH 6.0) to eliminate any solvent effects. Inositol hexanicotinate and the internal standard (mebendazole) were separated isocratically using a mobile phase of acetonitrile/phosphate buffer (35:65, v/v, pH 6.0) at a flow rate of 1.0 mL/min and a reverse-phase XTerra® MS C18 column (4.6 mm × 150 mm, 3.5 μm). The standard curve was linear over a concentration range of 1.5–100.0 μg/mL of inositol hexanicotinate in rat plasma. The HPLC method was validated with intra- and inter-day precisions of 1.55–4.30% and 2.69–21.5%, respectively. The intra- and inter-day biases were −0.75 to 19.8% and 2.58–22.0%, respectively. At plasma concentrations of 1.5–100 μg/mL, the mean recovery of inositol hexanicotinate was 99.6%. The results of a stability study indicated that inositol hexanicotinate was unstable in rat plasma samples, but was stable in acetonitrile extracts of rat plasma for up to 24 h at 4 °C. The assay is simple, rapid, specific, sensitive, and reproducible and has been used successfully to analyze inositol hexanicotinate plasma concentrations in a pharmacokinetic study using the rat as an animal model.