Typical chromatograms of determination of echinacoside (50 ng mL−1) and IS in plasma samples; (A) plasma sample 1 h after oral administration with liquid–liquid extraction; (B) plasma sample 1 h after oral administration with two-phase hollow fiber liquid phase microextraction.
A simple and solvent-minimized sample preparation technique based on two-phase hollow fiber liquid phase microextraction (HF-LPME) was developed and used to quantify the echinacoside in Parkinson's disease rat plasma following oral administration. Analysis was accomplished by reversed-phase high performance liquid chromatography (HPLC) with ultraviolet detection. The influence factors relevant to the HF-LPME processes were optimized. Under the optimized conditions, the preconcentration factor for echinacoside was 337. Calibration curves with reasonable linearity (r2 ≥ 0.9998) were obtained in the range of 5–750 ng mL−1. Intra-day and inter-day precision (RSD) were ≤5.43% and the limit of detection (LOD) for the analyte was 2.0 ng mL−1 (S/N = 3). The validated method has been successfully applied for pharmacokinetic studies of echinacoside in Parkinson's disease (PD) rat plasma after oral administration.