Comparisons of the bioavailability of icariin, icariside II, and epimedin C in rats after oral administration of total flavonoids of Epimedium brevicornu Maxim. and its three formulations

The low bioavailability of insoluble flavonoids in the total flavonoids of Epimedium brevicornu Maxim. (TFE) severely hindered its clinical efficacy exertion. This research attempted to evaluate the promoting effects of pharmaceutical strategies, including nanosuspensions (NS), cyclodextrin inclusion complexes (CD), and solid dispersions (SD), on the oral absorption of active components in TFE. A rapid ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was established to quantify ten pentenyl flavonoids of TFE in rat plasma. Good linearity was presented within the expected ranges (0.1 ∼ 10 ng/mL) in the calibration curves for ten analytes with an acceptable intra- and inter-day precision and accuracy of