Pharmacokinetics of eupalinolide A, eupalinolide B and hyperoside from Eupatorium lindleyanum in rats by LC/MS/MS.

A simple, selective, and sensitive LC/MS/MS method was developed and validated for simultaneous determination of eupalinolide A, eupalinolide B, and hyperoside in rat plasma. Plasma samples were processed by protein precipitation with acetonitrile. The three analytes, together with internal standard (IS, lysionotin), were separated on a Venusil MP-C18 column (50mm×2.1mm, 3µm) using a mobile phase of methanol and 10mM ammonium acetate (45:55, v/v) with isocratic elution. Mass spectrometric detection was performed by multiple-reaction monitoring mode via electrospray ionization source. Linear calibration curves were obtained for the following concentration range: 1.28-640ng/mL for EA; 1.98-990ng/mL for EB; and 2.00-1000ng/mL for HYP. The intra- and inter-day precision was less than 10.25%, and the accuracy was between 89.16% and 110.63%. The extraction recovery of the analytes and IS from rat plasma was above 88.75%. The validated method has been successfully applied to pharmacokinetic studies of the three analytes following intragastric administration of Eupatorium lindleyanum extract at a single dose of 100, 250, and 625mg/kg to Sprague-Dawley rats, respectively. The pharmacokinetic results may help to better understand the pharmacological actions of the herb E. lindleyanum.

Development and application of an analytical method for curdione quantification in pregnant Sprague-Dawley rats by LC-MS/MS.

The vaginal administration route suffers from relatively low absorption efficiency, which may hinder the identification of the toxicokinetics of curdione in pregnant women. A sensitive analytical method for determining the plasma concentration of curdione was developed and applied in the determination of curdione in pregnant Sprague-Dawley rats as a simulated model. Glimepiride was used as an internal standard and chromatographic separation was achieved on a Capcell Pak C18 MGIII column. A gradient elution profile with 0.5% formic acid (A)-0.5% formic acid-acetonitrile (B) was selected as mobile phase. The selected reaction monitoring mode was used for quantification based on the target fragment ions m/z 237.2 to m/z 135.1 for curdione and m/z 491.3 to m/z 352.1 for the glimepiride. The standard curve was linear over the range of 0.5-500 ng/mL for curdione in rat plasma and yielded a consistent peak pattern, even at the lower limit of quantitation of 0.5 ng/mL. The retention times of curdione and IS were 6.55 and 6.59 min, respectively. The mean recovery of curdione in rat plasma was 95.5-101.1%. The intra-day and inter-day precisions were between 2.35 and 9.08%. This LC-MS/MS method provides a simple and sensitive means for determining the plasma concentration.

Simultaneous quantification of curdione, furanodiene and germacrone in rabbit plasma using liquid chromatography-tandem mass spectrometry and its application to a pharmacokinetic study.

A simple, rapid and sensitive method was developed for the simultaneous quantification of curdione, furanodiene and germacrone in rabbit plasma using a LC-MS/MS analysis. The plasma sample preparation was a simple deproteinization by the addition of 3 vols of acetonitrile followed by centrifugation. The analytes and internal standard (IS) costunolide were separated on a Zorbax SB-C18 column (3.5 µm, 2.1 × 100 mm) with mobile phase of methanol-water (90:10, v/v) containing 0.1% formic acid at a flow rate of 0.3 mL/min with an operating temperature of 25°C. Detection was carried out by atmospheric pressure chemical ionization in positive ion selected reaction monitoring mode. Linear detection responses were obtained for the three test compounds ranging from 5 to 5000 ng/mL and the lower limits of quantitation were 5-10 ng/mL. The intra- and inter-day precisions (relative standard deviations) were within 9.4% for all analytes, while the deviation of assay accuracies was within ±10.0%. The average recoveries of analytes were >80.0%. All analytes were proved to be stable during all sample storage, preparation and analytical procedures. The method was successfully applied to the pharmacokinetic study of the three compounds after vaginal drug delivery of Baofukang suppository to rabbit.

The toxicokinetic profile of curdione in pregnant SD rats and its transference in a placental barrier system detected by LC-MS/MS.

The objective of this study was to determine the toxicokinetic profile of curdione in pregnant SD rats as well as the transference of curdione into the fetus through the placental barrier system using LC-MS/MS. Thirteen pregnant SD rats were treated with 7, 21 and 63 mg/kg curdione once daily from gestational day 6 (GD6) to GD15. Blood samples were collected at different time points on GD6 and GD15. Maternal plasma, placental plasma, placenta tissue, amniotic fluid and fetal tissue were collected for concentration analysis after all the animals were sacrificed following one repeated dose on GD19. The results indicated that Cmax, AUC(0₋t) and AUC(0₋∞) increased in a dose-dependent manner both on GD6 and GD15. At 7 mg/kg group, the total serum clearance value on GD15 was reduced to approximately 16.4% of that on GD6, and the volume of distribution was also significantly decreased (p<0.05). Curdione could be detected in the maternal plasma, placental plasma, placenta tissue, amniotic fluid and fetal tissue, and its concentration in the fetal tissue reached saturation at 21 mg/kg. In conclusion, curdione presents with the risk of accumulation in pregnant SD rats and may affect the fetus via transference through the placental barrier system.

A validated LC-MS/MS assay for the quantitative determination of curdione in rabbit plasma and its application to a pharmacokinetic study after administration of zedoary turmeric oil and bioavailability of the oil.

A selective and sensitive liquid chromatography tandem mass spectrometry method was developed for the first time for the identification and quantification of curdione in rabbit plasma after vaginal drug administration and intravenous administration of zedoary turmeric oil (ZTO) solution (10 mg/kg). The analysis was performed on a triple-quadrupole tandem mass spectrometer with multiple reaction monitoring mode via electrospray ionization source in positive ionization mode. After mixing with internal standard diazepam, plasma samples were extracted with ethyl ether-acetic ether (1:1, v/v). Chromatographic separation was carried out on a C18 column with gradient elution using a mixture of water and acetonitrile (both containing 0.1% formic acid) as mobile phases. Linearity ranged over 1.06-106 and 10.6-530 ng/mL (r ≥ 0.995) with the lower limit of quantfication 1.06 ng/mL. The intra- and inter-day precision relative standard deviation values were <12% and the accuracy relative error was from -10.6 to -6.1% at all quality control sample levels. The method was applied to a study of the pharmacokinetics of curdione after vaginal drug administration and intravenous administration of ZTO.

Analysis and pharmacokinetic study of curdione in Rhizoma Curcumae by UPLC/QTOF/MS.

An ultra-performance liquid chromatography-quadrupole time-of-flight/mass spectrometry (UPLC/QTOF/MS) method was established to determine the chemical components of curcuma rhizomes (Ezhu) and their pharmacokinetics. Chromatographic separation was performed by UPLC using a 1.8 µm column in order to obtain good resolution and increase the sensitivity of analysis. Accurate mass measurement within 5 ppm error for each ion produced in positive mode electrospray ionization and the subsequent QTOF product ions enabled 12 compounds to be identified. Several of the identified components, including ß-elemene, curcumol, germacrone and curdione, are thought to be the biologically active ingredients. Quantitative pharmacokinetic analysis was also carried out by UPLC/QTOF/MS. Using 20(S)-protopanoxadiol as an internal standard, samples were prepared by protein precipitation with methanol. Chromatographic separation was performed on an Agilent Extend-C18 column (2.1 × 50 mm, 1.8 µm) with acetonitrile (0.1% formic acid)-water (0.1% formic acid) for gradient elution. Curdione calibration plots were linear over the range of 0.1-12.2 µg/mL for curdione in plasma with the lower quantification limit being 6.5 ng/mL, and the recovery from plasma was about 105.2%. The RSD for both intra- and inter-day precision was <9.9%.

Determination of curdione in rabbit plasma by liquid chromatography mass spectrometry.

A sensitive and selective liquid chromatography mass spectrometry method for determination of curdione in rabbit plasma was developed. After addition of tramadol as internal standard (IS), protein precipitation by acetonitrile was used for sample preparation. Chromatographic separation was achieved on a Zorbax SB-C18 (2.1 × 50 mm, 3.5 µm) column with acetonitrile-0.1% formic acid as mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive-ion mode; selective ion monitoring was used for quantification using target fragment ions m/z 237 for curdione and m/z 264 for the IS. Calibration plots were linear over the range of 20-4000 ng/mL for curdione in plasma. The lower limit of quantification for curdione was 20 ng/mL. Mean recovery of curdione from plasma was in the range 94.3-98.4%. The RSD of intra-day and inter-day precision were both less than 9%. This method is simple and sensitive enough to be used in pharmacokinetic research for the determination of curdione in rabbit plasma.

A HPLC method for the analysis of germacrone in rabbit plasma and its application to a pharmacokinetic study of germacrone after administration of zedoary turmeric oil.

A validated new, simple and highly sensitive reversed-phase HPLC method is developed for studying the pharmacokinetics of germacrone after intravenous administration of zedoary turmeric oil (ZTO) oil-in-water microemulsion. The method did not require a complex and expensive equipment. A high extraction recovery (>80%) of germacrone was obtained. Linear calibration curves obtained with the peak-area ratio (y) of germacrone to internal standard (tanshinoneIIA) versus drug concentration (x) were found to be linear between 8.08 and 808 ng/ml. The limit of quantitation was 8.08 ng/ml. The monitored compounds were completely separated from others in ZTO and from endogenous species in plasma by HPLC. Pharmacokinetic investigations were performed on 18 male rabbits after intravenous administration of ZTO microemulsion via the ear vein at germacrone doses of 3.2, 6.4 and 9.6 mg/kg. The plasma concentration-time data fit to a two-compartment intravenous model with a weight of 1/C(2) (C: germacrone concentration in plasma). Germacrone exhibited linear pharmacokinetics after intravenous administration of ZTO microemulsion to rabbits over the germacrone dose range 3.2-9.6 mg/ml.