Rapid and sensitive analysis of parishin and its metabolites in rat plasma using ultra high performance liquid chromatography-fluorescence detection

A simple, rapid and sensitive ultra high performance liquid chromatography with fluorescence detection (UHPLC-FLD) method was developed and validated for quantification of parishin and its metabolites in rats. Plasma samples were prepared by protein precipitation and then analyzed using UHPLC-FLD system. Repeated optimization showed that parishin and its metabolites, including gastrodin, p-hydroxybenzyl alcohol, parishin B and parishin C, could be sensitively detected based on the autofluorescence when excitation and emission wavelengths were set at 225 nm and 295 nm, respectively. The limit of detections (LODs) of GAS, HBA, PB, PC and PA reached 0.6, 0.8, 1, 1 and 1 ng/mL, respectively. The linearity for all targets was within the range 2.5-5000 ng/mL and the correlation coefficient (r2) was larger than 0.999. Importantly, our method was almost free from matrix effects and the recoveries were higher than 80%. Additionally, our method also had high precision and accuracy for all analytes, presenting RSDs and REs within ±6% and ±14%, respectively. Finally, the validated UHPLC-FLD method was successfully applied for studying the pharmacokinetics of parishin following intragastrically administration in rats.