Solid-phase extraction–liquid chromatographic method for the determination and pharmacokinetic studies of albiflorin and paeoniflorin in rat serum after oral administration of Si–Wu decoction

A sensitive and rapid high-performance liquid chromatography (HPLC) method with solid-phase extraction (SPE) to simultaneously determine albiflorin and paeoniflorin in rat serum was described. Serum samples were pretreated with solid-phase extraction using Extract-Clean™ cartridges, and the extracts were analyzed by HPLC on a reversed-phase C18 column and a mobile phase of acetonitrile-0.03% formic acid (17:83 (v/v)) with ultraviolet detection at 230 nm. Pentoxifylline was used as the internal standard (IS). The linear ranges of the calibration curves were 29–1450 ng/ml for albiflorin and 10–2000 ng/ml for paeoniflorin. The intra- and inter-day precisions (R.S.D.) were ≤10.49% for albiflorin and ≤11.29% for paeoniflorin, respectively. Mean recovery was determined to be 89.75% for albiflorin and 85.82% for paeoniflorin. The limit of quantification was 29 ng/ml for albiflorin and 10 ng/ml for paeoniflorin, respectively. The validated method was applicable to pharmacokinetic studies of albiflorin and paeoniflorin from rat serum after oral administration of Si–Wu decoction. The pharmacokinetic study indicated that albiflorin and paeoniflorin had poor absorption and rapid elimination. This assay result was necessary for the pharmacokinetic evaluation of Si–Wu decoction.