An efficient in vitro and in vivo HPLC method for hydnocarpin in nanomicelles formulation

For quantitative and other related bioactive studies of hydnocarpin, there is a need to establish an efficient, specific and sensitive analytical method (in vitro and in vivo). In this paper, an efficient HPLC method has been established and validated to analyze hydnocarpin in a nanomicelle formulation for the first time. Various chromatographic conditions for in vitro and in vivo determinations were investigated, with the application examined by pharmacokinetics and tissue distribution studies. The analysis was carried out using an HPLC system with a Waters symmetry C18 column (4.6 × 150 mm, 5 µm) at 25°C with a detecting wavelength of 342 nm. Eluting at a rate of 1.0 mL/min, a 65% methanol and 35% acetic acid solution (0.1%) served as the mobile phase for the in vitro determinations while a 62% methanol and 38% acetic acid solution (0.1%) was used for in vivo analysis with isoliquiritigenin as internal standard. The established in vitro linearity range for hydnocarpin was 0.2-20 µg/mL (R(2) = 0.9996), with the biological (in vivo) samples following the same trend. The accuracy of the method was >99% (in vitro) and 92.4-105.3% (in vivo). Also, the precision met the acceptance criterion. These results indicate that the established method exhibited high specificity, accuracy, linearity and precision. Additionally, this efficient HPLC method was applied to pharmacokinetics and tissue distribution studies.