Simultaneous HPLC determination of ergosterol and 22,23-dihydroergosterol in Flammulina velutipes sterol-loaded microemulsion.

An efficient HPLC method was developed and validated for the simultaneous determination of ergosterol and 22,23-dihydroergosterol in Flammulina velutipes sterol-loaded microemulsions (FVSMs). The different chromatographic conditions for in vitro and in vivo determinations were investigated, with the application examined by tissue distribution. Chromatographic separation was achieved on an Inertsil ODS-SP (250 × 4.6 mm, 5 µm) analytical column using a mobile phase of 98% methanol (in vitro), and 93% methanol for stomach samples and 96% methanol for other samples (in vivo) at 1.0 mL/min. The sterol content was detected at 282 nm. The established in vitro linearity ranges for ergosterol and 22,23-dihydroergosterol were 0.58-72.77 µg/mL (r1 = 0.9999) and 0.59-73.25 µg/mL (r2 = 0.9999), respectively, with the biological (in vivo) samples following the same trend. The accuracy of the method was >99% (in vitro) and between 93%-108% (in vivo). The LOQ was 2.15 µg/L for ergosterol and 2.41 µg/L for 22,23-dihydroergosterol in the in vitro studies. Also, the precisions met the acceptance criterion. These results indicate that the established HPLC method was specific, linear, accurate, precise and sensitive for the separation and simultaneous determination of ergosterol and 22,23-dihydroergosterol.