Shijia Liu

Oral bioavailability and gender-related pharmacokinetics of celastrol following administration of pure celastrol and its related tablets in rats

ETHNOPHARMACOLOGICAL RELEVANCE Celastrol is a natural compound extracted from the traditional Chinese medicinal herb, Thunder God Vine (TGV). Owing to its potential anti-inflammatory and antitumor effects, celastrol has been considered as a promising candidate for drug development. AIM OF THE STUDY To establish a sensitive LC-MS/MS method to investigate the pharmacokinetic properties of celastrol in rats. Key pharmacokinetic issues of celastrol including oral bioavailability, comparative pharmacokinetics between pure compound and tablet preparation, as well as gender-related pharmacokinetic difference are to be addressed for the first time. MATERIALS AND METHODS Sprague-Dawley rats were administrated an intravenous dose (100 μg kg(-1)) of pure celastrol and an oral dose (1000 μg kg(-1)) of pure celastrol and TGV tablets (corresponding to 534 μg kg(-1) of celastrol), respectively. At different time points, the concentration of celastrol in rat plasma was determined by a sensitive and well-validated LC-MS/MS method. Main pharmacokinetic parameters including area under the plasma concentration-time curve (AUC), maximal plasma concentration (Cmax), the time for maximal concentration (Tmax) and mean residence time (MRT) were estimated by Drug and Statistic1.0 pharmacokinetic software (Chinese Pharmacological Association, Anhui, PR China). Statistical analysis was performed using two one-side t test with p-values less than 0.05 as the level of significance. RESULTS The standard curve of celastrol showed good linearity in the concentration range of 0.11~54.3 ng mL(-1) in our current method, with acceptable selectivity, precision, recovery, and stability. The oral absolute bioavailability of celastrol significantly increased from 17.06% for pure celastrol to 94.19% for TGV tablets containing equivalent celastrol. After oral administration of TGV tablets, the Cmax and AUC values of celastrol in female rats were (32.03±8.41) μg L(-1) and (379.49±118.19) μg h L(-1), which were significantly higher (p<0.01) than that in males with the values of (14.31±7.33) μg L(-1) and (188.17±92.33) μg h L(-1). CONCLUSION Celastrol administered orally in the rat was poorly absorbed into the systemic circulation. However, the poor absorption of celastrol could be greatly improved when celastrol-containing TGV tablets orally administered, and thereby the oral bioavailability of celastrol was significantly increased. As for gender difference, female rats showed significantly better absorption of celastrol than males.

Simultaneous characterization of prenylated flavonoids and isoflavonoids in Psoralea corylifolia L. by liquid chromatography with diode-array detection and quadrupole time-of-flight mass spectrometry

RATIONALE Prenylated flavonoids and isoflavonoids are widely distributed throughout the plant kingdom, with many biological effects. Psoralea corylifolia, which contains many kinds of prenylated components, has been widely used as a medicinal plant in Asia and India for thousands of years. The goal of this study was to characterize the components in P. corylifolia using a liquid chromatography with diode-array detection and quadrupole time-of-flight mass spectrometry (LC-DAD/Q-TOF-MS) method, and to elucidate the fragmentation behavior of the different prenyl substituent groups and their appropriate characteristic pathways in positive ion mode. METHODS The calculated accurate masses of the protonated molecules, the fragment ions, the retention behavior, and the data from UV spectra were used for identification of the components in P. corylifolia. RESULTS A total of 45 compounds, including 43 prenylated components, were identified or tentatively identified in P. corylifolia. Different diagnostic fragment ions and neutral losses were observed in different prenyl substructures: neutral loss of 56 Da (C(4)H(8)) and a fragment ion at m/z 69 (C(5)H(9)(+)) were generated by a prenyl chain; neutral losses of 42 Da (C(3)H(6)), 54 Da (C(4)H(6)), 15 Da (CH(3•)) and 16 Da (CH(4)) were observed in a ring-closed prenyl group; neutral losses of 72 Da (C(4)H(8)O), 60 Da (C(2)H(4)O(2)), 58 Da (C(3)H(6)O) and 18 Da (H(2)O) were detected in a 2,2-dimethyl-3,4-dihydroxydihydropyran ring; neutral losses of 72 Da (C(4)H(8)O), 60 Da (C(3)H(8)O) and 18 Da (H(2)O) were yielded from a 2,2-dimethyl-3-hydroxydihydropyran ring, a 2-(1-hydroxy-1-methylethyl)dihydrofuran ring or a 1-hydroxy-3-methylbut-3-enyl chain. CONCLUSIONS This method can be applied for analysis of prenylated components in P. corylifolia and other herbal medicines.

Quantification of limonin in human urine using solid-phase extraction by LC-MS/MS.

A highly sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of limonin in human urine using podophyllotoxin as internal standard. The analyte and IS were extracted with solid-phase extraction and separated by a rapid isocratic elution with 1% formic acid/methanol (v:v, 40:60) on an C(18) column (150 mm × 2.1 mm I.D.). The detection was performed by mass spectrometry in the multi-reaction-monitoring mode. The precursor to product ion transitions of m/z 471.3→161.2 and m/z 397.2→313.1 were used to measure the analyte and the IS. The assay was linear over the concentration range of 0.0783-10 ng/mL for limonin in human urine. The lower limit of quantification was 0.0783 ng/mL and the extraction recovery was larger than 76.7% for limonin. The inter- and intra-day precision of the method at three concentrations was less than 7.4%. The method was successfully applied to pharmacokinetic study of limonin in humans.

Development and Validation of a Liquid Chromatographic/Mass Spectrometric Method for the Determination of Saikosaponin a in Rat Plasma and its Application to Pharmacokinetic Study

A rapid and sensitive liquid chromatography/mass spectrometry (LC/MS) method was developed and validated for the determination of saikosaponin a in rat plasma. Saikosaponin a was extracted by protein precipitation with acetonitrile and the chromatographic separation was performed on a C18 column. The total analytical run time was relatively short (5.5 min) and the limit of assay quantifi cation (LLOQ) was 10 ng mL-1 using 100 μL of rat plasma. Saikosaponin a and the internal standard (felodipine) were monitored in selected ion monitoring (SIM) mode at m/z 779.2 and 382.0, respectively. The standard curve was linear over a concentration range from 10 to 5000 ng mL-1 and the correlation coeffi cients were greater than 0.999. The recoveries of saikosaponin a from plasma were larger than 82% and RSD of inter-day and intra-day assay were below 10%. The method described in this report was sensitive and specifi c and suitable for pharmacokinetic studies of saikosaponin a in rats.

Simultaneous determination of notoginsenoside R1 and ginsenoside Re in rat plasma by ultra high performance liquid chromatography with tandem mass spectrometry and its application to a pharmacokinetic study.

A rapid and high sensitive ultra high performance liquid chromatography with tandem mass spectrometry method for the simultaneous determination of notoginsenoside R1 and ginsenoside Re in rat plasma was developed. The analytes and internal standard, digoxin, were extracted from rat plasma via protein precipitation with methanol and separated on an Phenomenex Gemini C18 column within 2 min. Quantitation was performed on a triple quadrupole mass spectrometer employing electrospray ionization technique, operating in multiple reaction monitoring and positive ion mode. The precursor to product ion transitions monitored for notoginsenoside R1, ginsenoside Re, and internal standard were m/z 955.5→775.5, 969.6→789.1, and 803.6→283.1, respectively. The assay was validated with linear range of 1.9-380 ng/mL for notoginsenoside R1 and 0.5-100 ng/mL for ginsenoside Re. The intra- and interday precisions (RSD%) were within 8.96% for each analyte. The absolute recoveries were greater than 93% for R1 and 96% for Re. Each analyte was stable during all sample storage, preparation, and analytic procedures. The method was successfully applied to a pharmacokinetic study of Xuesaitong dispersible tablets in eight rats.

Determination of limonin in dog plasma by liquid chromatography–tandem mass spectrometry and its application to a pharmacokinetic study

A highly sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of limonin in beagle dog plasma using nimodipine as internal standard. The analyte and internal standard (IS) were extracted with ether followed by a rapid isocratic elution with 10 mm ammonium acetate buffer-methanol (26:74, v/v) on a C18 column (150 × 2.1 mm i.d.) and subsequent analysis by mass spectrometry in the multiple reaction monitoring mode. The precursor to product ion transitions of m/z 469.4 → 229.3 and m/z 417.2 → 122.0 were used to measure the analyte and the IS. The assay was linear over the concentration range of 0.625-100 ng/mL for limonin in dog plasma. The lower limit of quantification was 0.312 ng/mL and the extraction recovery was >90.4% for limonin. The inter- and intra-day precision of the method at three concentrations was less than 9.9%. The method was successfully applied to pharmacokinetic study of limonin in dogs.

Determination of typhaneoside in rat plasma by liquid chromatography–tandem mass spectrometry

A highly sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of typhaneoside in rat plasma using rutin as internal standard. The analyte and rutin (internal standard) were extracted with methanol followed by a rapid isocratic elution with 10 mM ammonium acetate buffer/methanol (v:v, 20:80) on an C(18) column (150 mm × 2.1 mm I.D.) and subsequent analysis by mass spectrometry in the multi-reaction-monitoring mode. The precursor to product ion transitions of m/z 769.3 → 314.1 and m/z 609.2 → 300.1 were used to measure the analyte and the internal standard. The assay was linear over the concentration range of 0.01-10 μg/mL for typhaneoside in rat plasma. The lower limit of quantification was 0.01 μg/mL and the extraction recovery was larger than 90.2% for typhaneoside. The inter- and intra-day precision of the method at three concentrations was less than 6.8%. The method was firstly applied to pharmacokinetic study of typhaneoside in rats.

Determination of bullatacin in rat plasma by liquid chromatography-mass spectrometry.

A liquid chromatography-mass spectrometry method has been developed and validated for the quantification of bullatacin, a bistetrahydrofuran annonaceous acetogenin, in rat plasma. Squamostatin-A was selected as the internal standard. Analytes were extracted from rat plasma by liquid/liquid extraction using ethyl acetate with high efficiency. The chromatographical separation was performed on an Agilent Zorbax SB-C₁₈ column (150 mm × 2.1 mm, 5 μm). The mobile phase consisted of methanol and deionized water (95:5, v/v) containing 0.01% (v/v) formic acid. The chromatographic run time was 7 min per injection and flow rate was 0.2 mL/min. The retention time was 3.22 and 5.23 min for internal standard and bullatacin, respectively. The elutes were detected under positive electrospray ionization and the target analytes quantified by selected ion monitoring mode (645.9 m/z for bullatacin and 661.9 m/z for squamostatin-A). The method was sensitive with the limit of quantitation at 0.5 ng/mL in 100 μL of rat plasma. Good linearity (r²=0.9998) was obtained covering the concentration of 0.5-2000 ng/mL. The intra- and inter-day assay precision ranged from 3.2 to 8.7% and 2.7 to 9.2%, respectively. In addition, the stability, extraction recovery and matrix effect involved in the method were also validated. This method was applied to measure the plasma bullatacin concentrations after a single tail vein intravenous administration of bullatacin in rats.

Analysis of isorhamnetin-3-O-neohesperidoside in rat plasma by liquid chromatography/electrospray ionization tandem mass spectrometry and its application to pharmacokinetic studies

AIM To establish an LC-MS/MS method for determination of isorhamnetin-3-O-neohesperidoside and investigate its application on pharmacokinetic study in rats. METHODS Eight rats were given 5 mg·kg(-1) isorhamnetin-3-O-neohesperidoside after intravenous administration. A highly sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of isorhamnetin-3-O-neohesperidosidein rat plasma using rutin as internal standard. The analytes and rutin (internal standard) were extracted with methanol followed by a rapid isocratic elution with 10 mmol·L(-1) ammonium acetate buffer/methanol (20 : 80, V/V) on a C18 column (150 mm × 2.1 mm, I.D., 5 μm) and subsequent analysis by mass spectrometry in the multi-eaction-monitoring mode. RESULTS The assays were linear over the concentration range of 0.01-10 μg·mL(-1) for isorhamnetin-3-O-neohesperidosidein rat plasma. The lower limit of quantifications for isorhamnetin-3-O-neohesperidoside was 0.01 μg·mL(-1). CONCLUSION The validated method is successfully applied to determine the plasma concentrations of isorhamnetin-3-O-neohesperidosidein in rats.

SIMULTANEOUS QUANTIFICATION OF NINE BIOACTIVE CONSTITUENTS IN DENGZHANXIXIN INJECTION BY UPLC-MS/MS

In this study, a rapid and comprehensive ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) method was developed for simultaneous determination of nine major bioactive constituents in Dengzhanxixin injection. The chromatographic separations were obtained on an Acquity UPLC BEH C18 column (50 mm × 2.1 mm I.D., 1.7 μm) by a linear gradient elution with the mobile phase consisting of A (water and 0.6% acetic acid) and B (acetonitrile and 0.6% acetic acid). The total analytical run time was relatively short (14 min). The analytes and two internal standards (ISs) were all monitored in a selected-ion reaction (SIR) mode with a negative electrospray ionization (ESI−) interface. The calibration curves of all analytes revealed good linear regression (r2 ≥ 0.9972) within test ranges. This method provided good precision with RSD of intra- and interday variation less than 1.26% and 2.51%, respectively. The validated method was then applied to quantify the nine major constituents in six batches of Dengzhanxixin injection, and the results indicated that the established method could be considered as an improved tool for quality control of Dengzhanxixin Injection.