HPLC-MS/MS method for determination of betamethasone in human plasma with application to a dichorionic twin pregnancy pharmacokinetic and placental transfers studies

Abstract Betamethasone (BET) is a synthetic glucocorticoid recommended for pregnant women at imminent risk of preterm birth before 34 weeks to reduce neonatal complications. There are different techniques to describe BET plasma quantification. However, none quantified the plasmatic concentration of BET in dichorionic (DC) twin pregnancies using LC-MS. Our objectives were to develop and validate a method for quantifying BET by LC-MS for pharmacokinetic (PK) and placental transfer studies in DC twin pregnancies. Blood samples were collected after intramuscular administration of a single BET dose containing 6 mg disodium phosphate + 6 mg acetate. BET was determined in plasma by liquid-liquid extraction. The method showed linearity in the range of 2-250 ng/mL, as well as precision and accuracy with a coefficient of variation and relative standard errors ≤ 15%. Additionally, the method presented selectivity and did not present matrix or carry-over effect. Stability tests also presented coefficient of variation and relative standard errors ≤ 15%. This is the first study which describe maternal and fetal plasma concentrations of BET in a DC twin pregnancy. The BET PK parameters were AUC0-∞, CL/F, Vd/F, Cmax, Tmax of 292.20 h*ng/mL, 39.08 L/h, 278.72 L, 25.55 ng/mL and 0.58 h, respectively. The placental transfer ratios of umbilical vein/maternal vein and intervillous space/maternal vein were 0.14 and 0.19 and 0.40 and 0.27 for both twins, respectively. However, a clinical study with more subjects is imperative to confirm this higher concentration of BET in the intervillous space

Development and validation of an LC-MS/MS method for pharmacokinetic study of lobetyolin in rats

Abstract A simple and selective liquid chromatography tandem with mass spectrometry (LC-MS/ MS) method for quantification of lobetyolin in rat plasma was developed and validated. Chromatographic separation was achieved on a Thermo ODS C18 reversed-phase column using 0.1% aqueous formic acid-methanol (50:50, v/v) in an isocratic elution mode at a flow rate of 0.4 mL.min-1. LC/MS performance was done in a positive ion ESI mode and the MS/MS transitions were monitored at m/z 419.3 [M+Na]+ → m/z 203.1 for lobetyolin and m/z 394.9 [M+Na]+ → m/z 231.9 for IS, respectively. The assay exhibited a linear dynamic range over 1.0-500 ng.mL-1 for lobetyolin in plasma. Both the precision (%RSD) and accuracy (RE%) were within acceptable criteria (<15%). Recoveries ranged from 87.0% to 95.6%, and the matrix effects were from 91.0% to 101.3%. After oral administration, the peak plasma concentration of lobetyolin was obtained as 60.1 ng.mL-1 at 1.0 h. The proposed LC-MS/MS method could be applied to a pharmacokinetic study employing 66 samples from 6 Wistar rats

Rapid and simultaneous determination of 10 active components of Psoraleae Fructus in beagle dog plasma using UPLC-MS/MS and its application in pharmacokinetic study / 中国中药杂志

An UPLC-MS/MS method for rapid and simultaneous determination of psoralen, isopsoralen, apigenin, genistein, bavaisoflavone, neobavaisoflavone, bavachin, bavachinin, psoralenoside, and isopsoralenoside of Psoraleae Fructus in beagle dog plasma was established, and then the method was applied in the pharmacokinetic study after oral administration of Psoraleae Fructus extract to beagle dogs. The pharmacokinetic parameters were calculated by the software of WinNonlin. A Waters HSS-T3 column(2.1 mm×100 mm,1.8 μm)was used for liquid chromatography separation with acetonitrile-water(containing 0.004% formic acid) as the mobile phase for gradient elution.The mass spectrometry was detected using electrospray ion source(ESI) under multi-reaction monitoring mode(MRM), as well as positive ion mode. Analysis time only takes 8.5 min. The methodological study in terms of specificity, accuracy, precision, linear range, recovery, matrix effect, and stability, was validated. The LC-MS analysis method established in this experiment was simple, specific, accurate, reliable, and meet the requirement of pharmacokinetic study in plasma after administration of Psoraleae Fructus extract to beagle dogs. Six beagle dogs received intragastric administration of Psoraleae Fructus extract, T_(max) of 10 chemical components is 1.92-5.67 h; among them, C_(max) of psoralen, isopsoralen, psoralenoside and isopsoralenoside is 383-3 613 ng·mL~(-1), and AUC_(0-∞) is 3 556-18 949 ng·h·mL~(-1), t_(1/2) is 2.45-4.83 h. C_(max) of the remaining six compounds is 0.81-19.9 ng·mL~(-1), AUC_(0-∞ )is 6.54-178 ng·h·mL~(-1), t_(1/2) is 2.95-7.29 h. The UPLC-MS/MS analysis method established in this study was proved to be accurate and sensitive that it can be applied to the pharmacokinetic study of beagle dogs after oral administration of Psoraleae Fructus extract.

A UPLC-MS/MS method for quantification of a novel doxorubicin conjugation prodrug in tumor cells / 药学学报

In this study, we developed a rapid and sensitive ultra high-performance liquid chromatographytandem mass spectrometry (UPLC-MS/MS) method to detect a sulfide bond doxorubicin conjugation prodrug (DOX-S-DOX) in human breast cancer tumor cells (MCF-7). The samples were prepared by acetonitrile precipitation using daunorubicin as internal standard (IS). A reversed phase C18 analytical column (Agilent Eclipse plus C18 RRHD 1.8 μm, 2.1 mm×50 mm) was utilized to separate the samples under gradient elution conditions. Mobile phase was a mixture of 0.1% formic acid in water and methanol at a flow rate of 0.4 mL ·min-1. The analysis was conducted on the mass spectrometer using an electrospray interface (ESI) in the positive ionization model. The calibration range was 20.0-400 ng·mL-1 with the correlation coefficients (r2) ≥ 0.99. The inter-and intra-assay precision (relative standard deviation, RSD%) of quality control samples was within 3.77%-8.35% and relative error (RE%) for accuracy was between -2.04% and 2.62%. Recovery (97.67%-104.2%) and matrix effect (104.8%-113.9%) were consistent, precise, and reproducible at different quality control levels in accordance with FDA guidance. The assay was successfully used in the cellular pharmacokinetics study of DOX-S-DOX, which may provide a clue to explore analytical methods of other prodrug forms of DOX.

Pharmacokinetic study of cholesteryl-phosphoryl zidovudine in rats / 国际药学研究杂志

Objective: To develop and validate methods for determination of cholesteryl-phosphoryl zidovudine(CPZ)and its metabolite zidovudine(AZT)in rat plasma and tissues,and use the methods to investigate the pharmacokinetics of CPZ in rats. Meth- ods: An HPLC-UV method was applied for the determination of CPZ in biological samples. The biological samples were precipitated with acetonitrile at first,and then CPZ was separated on a Diamonsil C 18 column(200 mm×4.6 mm I.D.,5 μm)with a gradient elution system comprising 90% methanol and 10% isopropanol(containing 2 mmol/L cetyl trimethylammonium bromide,2% acetic acid and 0.1% ammonium hydroxide). The eluent was monitored at 266 nm by UV detector. The determination of AZT in biological samples was performed by LC-MS/MS after it was extracted from the biological samples by liquid-liquid extraction with methyl tertbutyl ether. Chro- matographic separation was performed on a Poroshell 120 EC-C 18 column(50 mm×2.1 mm I.D.,2.7 μm). Using the mobile phase con- sisted of 35% methanol and 65% water containing 0.2% acetic acid,the column was eluted by an isocratic elution with the flow rate of 0.3 ml/min. Detection of AZT and the internal standard(IS)acetaminophen was achieved by ESI MS/MS in the positive ion mode using m/z 268.2→m/z 127.0 and m/z 152.1→m/z 110.0 transitions,respectively. Results: The linear ranges for the quantitative determina- tion of CPZ and AZT were 5-400 μg/ml and 2-500 ng/ml,respectively,when 50 μl plasma was analyzed. The lower limit for the quan- tification of CPZ and AZT was 5 μg/ml and 2 ng/ml,respectively. The inter-and intra-day precision values were below 15%,and the accuracy(relative error)was within ± 13.8% in all quality control samples. CPZ was quickly metabolized in rats,while AZT was oppo-site. The half-life of AZT was about 8 h. The distribution of CPZ and AZT was more in the liver,spleen and lungs of rats,and less in the heart and kidney. Conclusion: The methods completely meet the requirements for pharmacokinetic study of CPZ in rats. The phar- macokinetic results show that CPZ could release AZT targeting liver,spleen,and lungs in rats.

A sensitive bioanalytical method development and validation of cabozantinib in human plasma by LC-ESI-MS/MS

ABSTRACT A simple, sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the quantification of cabozantinib (CZ) in human plasma using cabozantinib-d4 (CZD4) as an internal standard (IS). Chromatographic separation was performed on Xbridge C18, 50 x 4.6 mm, 5 mm column with an isocratic mobile phase composed of 10mM Ammonium formate and Methanol in the ratio of (20:80 v/v), at a flow-rate of 0.7 mL/min. CZ and CZD4 were detected with proton adducts at m/z 502.2 ® 391.1 and 506.3 ® 391.2 in multiple reaction monitoring (MRM) positive mode respectively. Liquid-Liquid extraction method was used to extract the drug and IS. The method was validated over a linear concentration range of 5.0-5000.0 pg/mL with correlation coefficient (r2) ≥ 0.9994. This method demonstrated intra and inter-day precision within 1.95 to 2.37 and 2.93 to 9.3 % and Accuracy within 101.4 to 102.4 and 99.5 to 104.8 %. Cabozantinib was found to be stable throughout freeze-thawing cycles, bench top and postoperative stability studies

Sensitive Analysis and Pharmacokinetic Study of Berberrubine Using LC-MS/MS / 中草药·英文版

Objective To develop a sensitive and reproducible liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to evaluate the pharmacokinetic behavior of berberrubine (BRB) and its glucuronide (BRBG) in rats. Methods BRB, BRBG and tetrahydroberberine (THB, internal standard) were isolated by liquid-liquid extraction in rat biological samples. Chromatographic separation was achieved on an Agilent Zorbax Eclipse Plus C18 (2.1 mm × 50 mm, 3.5-Micron) with a gradient mobile phases primarily containing acetonitrile, water with 0.1% formic acid and 5 mm ammonium acetate. The analytes were monitored by MS/MS in positive electrospray ionization mode. Herein, the feasibility of new developed method was validated with respect to specificity, linearity, precision, accuracy, stability, extraction efficiency and matrix effect. The appropriate method was used for the pharmacokinetic study in rats. Results The new developed method could be applied to the pharmacokinetic study of BRB in rats. BRB and BRBG showed good linearity over the ranges of 2-1000 ng/mL and 5-2000 ng/mL, respectively, and precision was no more than 15%. The accuracy, specificity and stability could be acceptable. Conclusion The new method is sensitive and reproducible. In pharmacokinetic study, BRB showed nonlinear elimination property. Meanwhile, BRB was rapidly absorbed and widely distributed in various tissues with the highest exposure of BRB in kidney and liver. The absolute bioavailability of BRB was determined to be 8.2% and at the dose of 40 mg/kg, a total of 44% BRB was excreted in urine and feces.

Determination of sumatriptan in human plasma using liquid chromatography-mass spectrometry for pharmacokinetic study in healthy Korean volunteers

This study describes the development of an analytical method to determine sumatriptan levels in human plasma using high performance liquid chromatography (HPLC) coupled with triple quadrupole tandem mass spectrometry (MS/MS) and its application to a pharmacokinetic study in healthy Korean volunteers. A single 50 mg dose of sumatriptan was orally administered to twelve healthy volunteers (nine women and three men). The HPLC-MS/MS analytical method was validated with respect to its specificity, linearity, sensitivity, accuracy, precision, recovery, and stability. The calibration curve was linear over a concentration range of 0.3–100 ng/mL (r > 0.999). The lower limit of quantitation for sumatriptan in plasma was 0.3 ng/mL. The accuracy and precision of the analytical method were acceptable within 15% at all quality control levels. We compared plasma concentration-time curves as well as pharmacokinetic parameters such as the area under the curve (AUC) and maximum plasma concentration (C(max)). Both the mean AUC and C(max) of sumatriptan were 1.56 times higher in women than in men. These differences could be largely explained by the difference in body weight (44%) between women and men. The outcomes may provide insights into developing appropriate individualized treatment strategies.

Development of a simple and sensitive HPLC-MS/MS method for determination of diazepam in human plasma and its application to a bioequivalence study

We developed a simple, sensitive, and effective ultra-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) method with an electrospray ionization (ESI) interface in multiple reaction monitoring (MRM) and positive ion modes to determine diazepam concentrations in human plasma using voriconazole as an internal standard (IS). Diazepam and IS were detected at transition 285.2→193.1 and 350.2→127.1, respectively. After liquid-liquid extraction (LLE) using 1.2 ml of ethyl acetate:n-hexane (80:20, v/v), diazepam and IS were eluted on a Phenomenex Cadenza CD-C18 column (150 × 3.0 mm, 3 µm) with an isocratic mobile phase (10 mM ammonium acetate in water:methanol [5:95, v/v]) at a flow rate of 0.4 mL/min. The peak retention time was 2.32 min for diazepam and 2.01 min for IS, respectively. The lower limit of quantitation (LLOQ) was 0.5 ng/mL (S/N > 10) using 50 µL of plasma, and no interferences were observed in chromatograms. Our analytical method was fully validated and successfully applied to a bioequivalence study of two formulations of diazepam in healthy Korean volunteers.

Development and validation of analytical method for the determination of radotinib in human plasma using liquid chromatography-tandem mass spectrometry

This study describes the development of an analytical method to determine radotinib levels in human plasma using high performance liquid chromatography (HPLC) coupled with triple quadrupole tandem mass spectrometry (MS/MS) for pharmacokinetic application. Plasma samples were sequentially processed by liquid-liquid extraction using methyl tert-butyl ether, evaporation, and reconstitution. Analytes were separated and analyzed using HPLC-MS/MS in selected reaction monitoring mode, monitoring the specific transitions of m/z 531 to 290 for radotinib and m/z 409 to 238 for amlodipine (internal standard). The HPLC-MS/MS analytical method was validated with respect to selectivity, linearity, sensitivity, accuracy, precision, recovery, and stability. Calibration curves were linear over a concentration range 5–3,000 ng/mL with correlation coefficients (r) > 0.998. The lower limit of quantification for radotinib in plasma was 5 ng/mL. The accuracy and precision of the analytical method were acceptable within 15% at all quality control levels. This method was suitable to determine radotinib levels in human plasma because of its simplicity, selectivity, precision, and accuracy.

Liquid Chromatographic Assay for the Analysis of Kanamycin sulphate nanoparticles in Rat after intramuscular administration: Application to a Pharmacokinetic Study.

A rapid reversed-phase high performance liquid chromatography (RP-HPLC) method was developed for the determination of Kanamycin sulphate (KS) in PLGA nanoparticle formulation. A new formulation of KS loaded PLGA nanoparticles (NPs) was prepared by double (multiple) emulsion process in our laboratory. The desired chromatographic separation was achieved on a Phenomenex C18column under isocratic conditions using UV detection at 205 nm. The optimized mobile phase consisted of a mixture of 0.1 M disodium tetraborate (pH 9.0) and water (25:75, v/v) supplemented with 0.5 g/L sodium octanesulphonate at a flow rate of 1 mL/min. The linear regression analysis for the calibration curves showed a good linear correlation over the concentration range of 120-840µg/ml, with correlation coefficients of (r2 0.9997). The system was found to construct sharp peaks for KS and IS with retention times of 4.08 and 5.49 min, respectively. Transmission electron microscopy studies on MFX NPs demonstrated particle size < 100 nm. An average encapsulation efficiency of 74.34% was obtained for NPs. In vitro studies showed zero-order release and about 95% drug being released within 12 days in PBS (pH 7.4). In conclusion, the proposed optimized method was successfully applied for the determination of in vitro and in vivo release studies of KS NPs.

Pharmacokinetic profiles of falcarindiol and oplopandiol in rats after oral administration of polyynes extract of Oplopanax elatus / 中国天然药物

Polyynes, such as facarindiol (FAD) and oplopandiol (OPD), are responsible for anticancer activities of Oplopanax elatus (O. elatus). A novel approach to pharmacokinetics determination of the two natural polyynes in rats was developed and validated using a liquid chromatography-electrospray ionization-mass spectrometry (LC-MS) method. Biosamples were prepared by liquid-liquid extraction using ethyl acetate/n-hexane (V : V = 9 : 1) and the analytes were eluted on an Agilent ZORBAX Eclipse Plus C18 threaded column (4.6 mm × 50 mm, 1.8 μm) with the mobile phase of acetonitrile-0.1% aqueous formic acid at a flow-rate of 0.5 mL·min(-1) within a total run time of 11 min. All analytes were simultaneously monitored in a single-quadrupole mass spectrometer in the selected ion monitoring (SIM) mode using electrospray source in positive mode. The method was demonstrated to be rapid, sensitive, and reliable, and it was successfully applied to the pharmacokinetic studies of the two polyynes in rat plasma after oral administration of polyynes extract of O. elatus.

LC-MS/MS method for determination of tripterine in plasma： pharmacokinetic study in Beagles / 中国中药杂志

To establish a LC-MS/MS method for determination of tripterine in Beagle plasma and study its pharmacokinetics after oral administration of tripterygium tablet. Plasma samples were extracted with dichloromethane and separated on a Phenomenex Luna C₈ (2.0 mm×50 mm, 3 μm) column with methanol-acetonitrile isopropanol(1∶1)-1‰formic acid (15∶55 ∶30) as the mobile phase. Tripterine ([M+H] ⁺, m/z 451.3/201.1) and internal standard prednisolone ([M+H] ⁺, m/z 361.1/147.1) were monitored in multiple reaction monitoring (MRM). The concentration-time curves were simulated by drug and statistic software 1.0 and the pharmacokinetic parameters were calculated. There was a good linear relationship between peak area ratio and concentration of tripterine and internal standard prednisolone within range of 0.680 0-136.0 μg•L⁻¹. The limit of quantitation was 0.680 0 μg•L⁻¹ and the intra- and inter-day precision was within 6.15%. The absolute recovery rate was between 50.42% to 51.65%. The concentration-time curves were consistent with the one-compartment model(w=1/cc). The main pharmacokinetic parameters after a single dose were as follows： Cmax (35.64±9.540) μg •L⁻¹,Tmax(2.62±0.69) h,T1/2(2.93±0.29) h, CL (0.308±0.056) L•kg⁻¹•h⁻¹, AUC0-12 (131.16±31.94) μg•L•h⁻¹, AUC0-∞ (142.83±37.57) μg•L•h⁻¹. The established LC-MS/MS method was proved to be sensitive, accurate and convenient, suitable for the pharmacokinetic study of Tripterygium tablet in Beagle dogs.

Development and validation of a UPLC-MS/MS method for the quantification of acetaminophen in human plasma and its application to pharmacokinetic studies

We developed an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the determination of acetaminophen concentration in human plasma. Following protein precipitated extraction, the analytes were separated and analyzed using an UPLC-MS/MS in the multiple reaction monitoring (MRM) mode with the respective [M+H]+ ions, m/z 152.06 → 110.16 for acetaminophen and m/z 180.18 → 138.12 for phenacetin (internal standard, IS). The method showed a linear response from 1 to 100 µg/mL (r > 0.9982). The limit of quantitation for acetaminophen in plasma was 1 µg/mL. The intra- and inter-day accuracy ranged in the ranges of 94.40–99.56% and 90.00–99.20%, respectively. The intra- and inter-day precision ranged in the ranges of 2.64–10.76% and 6.84–15.83%, respectively. This method was simple, reliable, precise and accurate and can be used to determine the concentration of acetaminophen in human plasma. Finally, this fully validated method was successfully applied to a pharmacokinetic study of acetaminophen in healthy volunteers following oral administration.

Fabrication of multiwalled carbon nanotube-surfactant modified sensor for the direct determination of toxic drug 4-aminoantipyrine☆ / 药物分析学报

A multi-walled carbon nanotube (MWCNT)-cetyltrimethylammonium bromide (CTAB) surfactant composite modified glassy carbon electrode (GCE) was developed as a novel system for the determination of 4-aminoantipyrine(AAP). The oxidation process was irreversible over the pH range studied and exhibited a diffusion controlled behavior. All experimental parameters were optimized. The combination of MWCNT-CTAB endows the biosensor with large surface area, good biological compatibility, electricity and stability, high selectivity and sensitivity. MWCNT-CTAB /GCE electrode gave a linear response for AAP from 5.0 × 10-9 to 4.0 × 10-8 M with a detection limit of 1.63 × 10-10 M. The modified electrode showed good selectivity against interfering species and also exhibited good reproducibility. The present electrochemical sensor based on the MWCNT-CTAB/GCE electrode was applied to the determination of AAP in real samples.

Liquid chromatography-tandem mass spectrometry method for the estimation of adefovir in human plasma：Application to a pharmacokinetic study / 药物分析学报

An analytical method based on solid phase extraction was developed and validated for analysis of adefovir in human plasma. Adefovir-d4 was used as an internal standard and Synergi MAX RP80A (150 mm × 4.6 mm, 4μm) column provided the desired chromatographic separation of compounds followed by detection with mass spectrometry. The method used simple isocratic chromato-graphic condition and mass spectrometric detection in the positive ionization mode. The calibration curves were linear over the range of 0.50–42.47 ng/mL with the lower limit of quantitation validated at 0.50 ng/mL. Matrix effect was assessed by post-column infusion experiment to monitor phospholipids and post-extraction addition experiment was performed. The degree of matrix effect for adefovir was determined as 7.5%and ion-enhancement in five different lots of human plasma was 7.1%and had no impact on study samples analysis with 4.5 min run time. The intra- and inter-day precision values were within 7.7% and 7.8%, respectively, for adefovir at the lower limit of quantification level. Validated bioanalytical method was successfully applied to clinical sample analysis.

Quantification of sibutramine and its two metabolites in human plasma by LC-ESI-MS/MS and its application in a bioequivalence study / 药物分析学报

Obesity can be considered as a chronic illness of epidemic proportion and its incidents have increased exponentially in recent years.The use of anti-obesity drugs such as sibutramine is somewhat helpful.There is a need to quantify such drugs in biological samples,which is generally quite difficult.In this report,we developed and validated a simple,sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of sibutramine (SB) and its two metabolites N-des methyl sibutramine (DSB) and N-di desmethyl sibutramine (DDSB) in human plasma.Zorbax SBC18 (4.6 mm × 75 mm,3.5 μm,80 (A)) analytical column and 5 mM ammonium formate:acetonitrile (10∶90,v/v) mobile phase were used for chromatographic separation of SB,DSB and DDSB.Multiple reaction monitoring (MRM) in the positive mode was used to detect SB,DSB and DDSB at m/z 280.3/124.9,266.3/125.3 and 252.2/124.9,respectively.Liquid liquid extraction was used for the extraction of analytes and internal standard from human plasma.This method was validated over a linear concentration range of 10.0-10,000.0 pg/mL for SB,DSB and DDSB with correlation coefficients (r) of ≥0.9997.The drug and the two metabolites were stable in plasma samples.The validated method was successfully applied in a bioequivalence and pharmacokinetic study with human volunteers under fasting condition.

Quantification of desloratadine in human plasma by LC-ESI-MS/MS and application to a pharmacokinetic study / 药物分析学报

A simple,sensitive,and specific liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for the quantification of desloratadine (DL) in human plasma using desloratadine-d5 (DLD5) as an internal standard (IS).Chromatographic separation was performed using an Xbridge C18 column (50 mm × 4.6 mm,5 μm) with an isocratic mobile phase composed of 10 mM ammonium formate:methanol (20∶80,v/v),at a flow rate of 0.7 mL/min.DL and DLD5 were detected with proton adducts at m/z 311.2→259.2 and 316.2→264.3 in multiple reaction monitoring (MRM)positive modes,respectively.Liquid-liquid extraction (LLE) method was used to extract the drug and the IS.The method was validated over a linear concentration range of 5.0-5000.0 pg/mL with a correlation coefficient of (r2)(≥)0.9994.This method demonstrated intra- and inter-day precision within 0.7-2.0％ and 0.7-2.7％,and an accuracy within 101.4-102.4％,and 99.5-104.8％.DL was found to be stable throughout the freeze-thaw cycles,bench-top,and postoperative stability studies.This method was successfully applied in the analysis of plasma samples following oral administration of DL (5 mg) in 35healthy Indian male human volunteers under fasting conditions.

Determination of Shionone in Rat Plasma by HPLC and Its Pharmacokinetic study / 中草药·英文版

Objective To develop a sensitive, simple, and accurate method for the determination of shionone in rat plasma after ig administration of Asteris Radix petroleum ether extract (RAPE). Methods The separation was achieved by HPLC on a RP18 column (150 mm × 3.9 mm, 5μm) with a mobile phase composed of acetotitrile-0.05% phosphoric acid water (98: 2) at a flow rate of 1.0 mL/min. UV Detector was set at 200 nm and friedelin was chosen as an internal standard. Results The linear range of the standard curves was (0.3443-22.0) μg/mL with the correlation coefficient of 0.9968. The intra- and inter-day precisions were all below 10% and the relative error was -3.5%-1.1%.Conclusion The developed method can be successfully applied to the pharmacokinetic study. After ig administration of RAPE, T1/2(ka) is (33.09 ± 7.32) min and T1/2(ke) is (84.95 ± 22.34) min.