A sensitive, simple, and accurate method for the determination and pharmacokinetic study of vanillic acid in rat plasma was developed using reverse-phase HPLC with UV detection after oral administration of the traditional Chinese medicine preparation of the Di-Gu-Pi decoction. Plasma samples taken from rats were extracted with methanol. The constituent vanillin acid was separated on a C18 stationary phase and a mobile phase of acetonitrile-water (15:85, v/v) (adjusted to pH 3.0 using phosphoric acid), with a UV detector setting at 260 nm. The validated HPLC method developed was used to determine the pharmacokinetic profile of vanillin acid in rat plasma after administration of the Di-Gu-Pi decoction.

Sambucus chinensis L. is a native perennial herb distributed throughout China. In traditional Chinese medicine (TCM), this herb is known as Lu-Ying. Ursolic acid is the major effective constituent of Lu-Ying. A rapid, sensitive, and accurate liquid chromatography-mass spectrometry (LC-MS) method for the determination of ursolic acid in rat plasma was developed and validated. Plasma samples taken from rats that had received Lu-Ying extract orally were acidified with acetic acid and then extracted with a mixture of hexane-dichloromethane-2-propanol (20:10:1,v/v/v). Separation of ursolic acid was accomplished on a C18 column interfaced with a single quadrupole mass spectrometer. The mobile phase consisting of methanol and water (95:5, v/v) was delivered at a flow rate of 1.0 ml/min. Atmospheric pressure chemical ionization was operated in negative-ion mode. Using selected ion-monitoring mode, the deprotonat-ed molecules [M-H] at m/z 455 and 469 were used to quantify ursolic acid and glycyrrhetic acid (internal standard), respectively. The assay was shown to be linear over the range of 10-1000 ng/ml (r> 0.9960) with a lower limit of quantification of 10 ng/ml. The method was shown to be reproducible and reliable with intraday precision below 7.8%, inter-day precision below 8.1%, accuracy within ±4.3%, and mean extraction recovery excess of 83.6%, which were all calculated from the blank plasma sample spiked with ursolic acid at three concentrations of 20, 200, and 800ng/ml. The LC-MS method has been successfully applied to pharmacokinetic studies of ursolic acid after oral administration of LuYing ethanolic extract (at a dose containing 80.32 mg/kg ursolic acid) to rats. The main pharmacokinetic parameters were: ℓ1/2, 4.3 h; Ke,0.16 1/h; ℓmax, 1.0 h; Cmax, 294.8 ng/ml; A UC0-t and A UC0- 1007.1 ng•h/ml and 1175.3 ng•h/ ml, respectively.

目的：测定不同产地川芎中川芎嗪的含量以控制其质量。方法：采用Xttera C18（4.6mm×250mm，5μm）色谱柱，以甲醇－10mmol．L-l醋酸铵（pH=9.05）－四氢呋喃（19:81:2）为流动相，流速为0.6·mLmin-1，柱温为室温，检测波长为281nm，以外标法测定了川芎药材中川芎嗪的含量。结果：川芎嗪在0.3－24μg．mL-l(r=0.9995)的浓度范围内呈线性关系。川芎嗪的平均回收率（n=6）为98.3%。结论：该方法准确、简便、易行，可用于质量控制。

A simple and sensitive high-performance liquid chromatographic method has been developed for determination of chlorogenic acid in rat plasma. Chlorogenic acid was extracted from plasma samples with methanol. HPLC analysis of the extracts was performed on a C18 column (250 mm × 4.6 mm i.d.5 µm particles). The mobile phase was acetonitrile -1% formic acid (9:91, v/v). The calibration plot was linear over the range 0.0420-2.10 µg mL-1 and the lower limit of quantification was 0.0420 μg mL-1. The method was reproducible and reliable with intra-day pre-cision better than 8.2%, inter-day precision better than 9.1 %, accuracy within ±8.3%, and mean extraction recovery above 84.4%. The validated method was successfully applied to pharmacokinetic studies of photogenic acid in rat plasma after administration of Luying decoction.