Determination of ferruginol in rat plasma via high‐performance liquid chromatography and its application in pharmacokinetics study

Ferruginol, a diterpene phenol, has recently received attention for its extensive pharmacological properties, including anti‐tumor, antibacterial, cardio‐protective and gastroprotective effects. In the present study, a high‐performance liquid chromatographic (HPLC) method was developed for determination of ferruginol in rat plasma and applied for the pharmacokinetics study. The HPLC assay was performed with a VP ODS‐C₁₈ column. The mobile phaseconsisted of methanol and 1% acetic acid solution (90:10, v/v). The flow rate was 1.0 mL/min, and the wavelength was set at 270 nm. This method was linear over the studied range of 0.1–10.0 µg/mL for ferruginol. The correlation coefficient was 0.9998. The intra‐day and inter‐day precisions were better than 4 and 5%, respectively. The extraction recovery and accuracy were greater than 97 and 96%, respectively. The detection limit was 30 ng/mL. The mean maximum concentration of ferruginol in rat plasma was 3.14 µg/mL at 40 min after oral administration at a dose of 20 mg/kg. Ferruginol was absorbed quickly p.o. with t_1/2ka = 14.86 min and had a high rate of elimination with t_1/2 = 41.73 min. The pharmacokinetic process of ferruginol in rat was well described with a one‐compartment model. Copyright © 2009 John Wiley & Sons, Ltd.     

Validated HPLC method for the quantitative determination of CoQ(10) in dog plasma and its application to a pharmacokinetic study

Coenzyme Q₁₀ (CoQ₁₀) is a naturally occurring compound located in all membranes throughout the cell. A rapid and sensitive HPLC method was developed to determine the concentration of CoQ₁₀ in dog plasma using a surrogate matrix. Chromatographic separation was carried out on a Diamonsil C₁₈ column with the UV detector set at 275 nm. Methanol–2‐propanol (40:60, v/v) was used as a mobile phase delivered at a flow rate of 1.0 mL/min. Calibrators were prepared using blank plasma–K₂HPO₄ buffer (50 mm , pH 8.0)–saline (1:3:6, v/v/v) as surrogate matrix. It was shown that the surrogate matrix had similar properties to dog plasma for CoQ₁₀ in extraction, freeze–thaw and stability. The assay was linear over the concentration range of 0.10–100 µg/mL. The intra‐ and inter‐day precisions were within 13.3% in terms of relative standard deviation (RSD%) and the accuracy was within ±7.5% in terms of relative error. This simple and reproducible HPLC method with less plasma volume (0.4 mL) and adequate sensitivity was successfully applied to pharmacokinetic studies of CoQ₁₀ in dogs and an investigation of the effect of CoQ₁₀ formulation on CoQ₁₀ baseline levels. Copyright © 2010 John Wiley & Sons, Ltd.     

Determination of tectoridin in rat plasma by high‐performance liquid chromatography and its application to pharmacokinetic studies

A simple, specific and sensitive HPLC method with UV detection was developed and validated for the determination of tectoridin in rat plasma for the first time. Chromatographic separation was performed on a Welchrom^TM C₁₈ column (150 × 4.6 mm, i.d., 5 µm) at a flow rate of 1.0 mL min^?1, using a mixture of methanol–2% HAc aqueous solution (31:69, v/v) as the mobile phase with UV detection at 266 nm. The calibration curves for tectoridin were linear over the concentration range of 1.10–274.40 µg mL^?1 in rat plasma. The intra‐ and inter‐day accuracies (RE) were within ?3.23% and 4.11%. The intra‐ and inter‐day precisions (RSD) were not more than 2.74 and 4.72%, respectively. The present method was successfully applied to the pharmacokinetic studies of tectoridin in rats after intravenous administration of three different doses. Copyright © 2009 John Wiley & Sons, Ltd.     

Improved HPLC method for doxorubicin quantification in rat plasma to study the pharmacokinetics of micelle-encapsulated and liposome-encapsulated doxorubicin formulations

An improved simple, rapid and accurate HPLC method for quantification of doxorubicin derived from micelle-encapsulated or liposome-encapsulated doxorubicin formulation in rat plasma was described. The mobile phase consisting of a mixture of methanol-water [containing 0.1% formic acid anhydrous and 0.1% ammonia solution (25%), pH 3.0], 60:40, was delivered at a flow rate of 1.0 mL/min. Sample preparation for micelle- or liposome-encapsulated doxorubicin in rat plasma were achieved directly by protein precipitation with acetonitrile. Doxorubicin and daunorubicin (internal standard, IS) were separated on a C(18) reversed-phase HPLC column and quantified by a fluoresence detection with an excitation wavelength of 475 nm and an emission wavelength of 580 nm. The linearity was obtained over the range of 5.0-1000.0 ng/mL and 1.0-200.0 microg/mL for doxorubicin and the lower limit of quantitation was 5.0 ng/mL. For each level of quality control samples, inter- and intra-assay precision was less than 9.6 and 5.1% (relative standard deviation), respectively, and percentage error was within +/-2.6%. The extraction recoveries of doxorubicin in the range of 10 ng/mL to 100 microg/mL in rat plasma were between 94.1 and 105.6%. This method was successfully applied to the pharmacokinetic study of doxorubicin formulations after i.v. administration to rats.     

Determination of gambogic acid in dog plasma by high-performance liquid chromatography for a pharmacokinetic study

A rapid, simple and sensitive high-performance liquid chromatography method for the quantification of gambogic acid in dog plasma was developed and validated. After acidification with hydrochloric acid, dog plasma was extracted with ethyl acetate and determined by HPLC. The analysis was carried out on a reversed-phase C(18) analytical column. The mobile phase consisted of a mixture of methanol-0.05% phosphoric acid (94:6, v/v), and the column temperature was maintained at 35 degrees C. A constant mobile phase flow rate of 1.0 mL/min was employed throughout the analyses. The ultraviolet detector was set at 360 nm. Chromatographic separation was achieved in less than 10 min and the calibration curve was linear over a concentration range of 0.156-20 microg/mL. The intra-assay and inter-assay variability values were less than 10.0%. The accuracy ranged from 93.0 to 104.2%. The established method has been successfully applied to a pharmacokinetic study of gambogic acid in dogs.     

PEEK tube‐based online solid‐phase microextraction–high‐performance liquid chromatography for the determination of yohimbine in rat plasma and its application in pharmacokinetics study

Yohimbine is a novel compound for the treatment of erectile dysfunction derived from natural products, and pharmacokinetic study is important for its further development as a new medicine. In this work, we developed a novel PEEK tube‐based solid‐phase microextraction (SPME)–HPLC method for analysis of yohimbine in plasma and further for pharmacokinetic study. Poly (AA‐EGDMA) was synthesized inside a PEEK tube as the sorbent for microextraction of yohimbine, and parameters that could influence extraction efficiency were systematically investigated. Under optimum conditions, the PEEK tube‐based SPME method exhibits excellent enrichment efficiency towards yohimbine. By using berberine as internal standard, an online SPME‐HPLC method was developed for analysis of yohimbine in human plasma sample. The method has wide linear range (2–1000 ng/mL) with an R ² of 0.9962; the limit of detection was determined and was as low as 0.1 ng/mL using UV detection. Finally, a pharmacokinetic study of yohimbine was carried out by the online SPME‐HPLC method and the results have been compared with those of reported methods.     

Simultaneous detection of four flavonoids and two alkaloids in rat plasma by LC–MS/MS and its application to a comparative study of the pharmacokinetics between Abri Herba and Abri mollis Herba extract after oral administration

Abri Herba and Abri mollis Herba both were important members of the Leguminosae family in southwestern China. Abri mollis Herba was often used as Abri Herba due to their proximity, but there are few studies on pharmacokinetics to compare their main identical active compositions. A sensitive and selective high‐performance liquid chromatography with tandem mass spectrometry method in the positive/negative electrospray ionization switching mode was developed and validated for the simultaneous analysis of four flavonoids and two alkaloids in rat plasma. The chromatographic separation was carried out on a C18 column with a gradient mobile phase consisting of methanol and 0.5% acetic acid. The detection of the target compounds was conducted in multiple‐reaction monitoring mode with a hybrid triple quadrupole linear ion trap mass spectrometer equipped with positive/negative ion‐switching electrospray ion source. The differences in pharmacokinetics were discovered, which indicated that the substitution between them is some degree of irrationality. The validated method was successfully applied to pharmacokinetic study of the six components in male rat plasma after oral administration of Abri Herba and Abri mollis Herba extract and the results in the study would provide a useful guide for the clinical application of Abri Herba with those in Abri mollis Herba.     

Determination of GL‐V9, a derivative of wogonin,in rat plasma by UPLC–MS/MS and its application to a pharmacokinetic study after oral and pulmonary administration

GL‐V9, a derivative of wogonin, shows much more potent anticancer properties than wogonin. In this study, a selective, sensitive and rapid ultra‐high‐performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS) method was developed and validated for the determination of GL‐V9 in rat plasma. Plasma samples were processed using methanol to precipitate protein. Chromatographic separation of analytes was achieved on a C₁₈ column using gradient elution within 4.5 min. The mobile phase consisted of acetonitrile and water including 0.1% (v/v) formic acid and 5 mm ammonium acetate. GL‐V9 and caffeine (internal standard) were monitored by positive electrospray triple quadrupole mass spectrometer and quantified using multiple reaction monitoring (MRM) mode with the transitions of m/z 410.20 → 126.10 (GL‐V9) and 195.10 → 138.00 (IS: caffeine), respectively. Good linearity was obtained over the range of 2–1000 ng/mL (R² > 0.99) and the extraction recovery was 101.91 ± 11.34%. The intra‐ and inter‐day precision variations were small (RSD 1.35–6.96%) and the relative error (RE) of accuracy was ?7.35–6.27%. The established and validated UPLC–MS/MS method was successfully applied to study the pharmacokinetic behavior of GL‐V9 after administration through different delivery routes. The results demonstrated that pulmonary delivery exhibited a greater advantage in terms of improving bioavailability compared with oral administration.     

An HPLC method for the quantitation of 3‐pentylbenzo[c]thiophen‐1(3H)‐one in dog plasma and its application to a pharmacokinetic study

A simple, sensitive and reproducible high‐performance liquid chromatography (HPLC) assay method was developed for the estimation of 3‐pentylbenzo[c]thiophen‐1(3H)‐one (S₅), a potential anti‐ischemic stroke agent, in dog plasma. The analytical procedure involves protein precipitation of S₅ and nobiletin (internal standard) from dog plasma with acetonitrile. Chromatographic separation was achieved on Sapphire C18 analytical column with methanol–water (80:20, v/v) as mobile phase. The eluate was monitored using a UV detector set at 260 nm. The calibration curves were linear over the range of 0.2–20 µg/mL. Absolute recoveries of S₅ were 79.2–86.1% from dog plasma. The intra‐ and inter‐day relative standard deviation precisions were <7 and 5%, respectively. The method was successfully applied to the pharmacokinetic study of S₅ in beagle dogs. Copyright © 2014 John Wiley & Sons, Ltd.     

人血清中地尔硫高效液相色谱法测定及药代动力学参数

建立了反相高效液相色谱法监测人口服地尔硫艹卓缓释片后血药浓度。血样用正己烷－氯仿－异丙醇混合溶剂（６０４０５）提取后，以Ｃ１８化学键合硅胶为固定相，甲醇－水－三乙胺为流动相，安定为内标，在２３９ｎｍ波长处定量检测。血药浓度在１５～３００μｇ／Ｌ范围内线性关系良好，最低检测浓度为３μｇ／Ｌ。批内（ｎ＝７）及批间（ｎ＝５）测定相对标准偏差分别小于６．８％和８．４％，回收率为９１％～１０４％。监测了８名健康人口服盐酸地尔硫艹卓缓释片后的不同时间的血药浓度变化，计算了有关的药代动力学参数。     

Determination of chidamide in rat plasma by LC‐MS and its application to pharmacokinetics study

A sensitive and selective liquid chromatography mass spectrometry method for determination of chidamide in rat plasma was developed. After addition of linezolid as internal standard, protein precipitation by acetonitrile–methanol (9:1, v/v) was used as sample preparation. Chromatographic separation was achieved on a Zorbax SB‐C₁₈ (2.1 × 150 mm, 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 mode was used for quantification using target fragment ions m/z 391.5 for chidamide and m/z 338.5 for the IS. Calibration plots were linear over the range of 10–2000 ng/mL for chidamide in rat plasma. The lower limit of quantification for chidamide was 10 ng/mL. The mean recovery of chidamide in plasma was in the range of 86.6–92.1%. The coefficients of variation of intra‐day and inter‐day precision were both <12%. This method is simple and sensitive and was applied successfully in a pharmacokinetic study of chidamide to rats. Copyright © 2013 John Wiley & Sons, Ltd.     

Quantification of homoegonol in rat plasma using liquid chromatography–tandem mass spectrometry and its pharmacokinetics application

Homoegonol is a biologically active neolignan isolated from Styrax species with cytotoxic, antimicrobial, anti‐inflammatory and anti‐asthma activities. For the quantification of homoegonol in rat plasma, a selective and sensitive liquid chromatography–tandem mass spectrometric method was developed and validated for the first time using protein precipitation with methanol as a sample clean‐up procedure. The analytes were separated in an Atlantis dC₁₈ column using a gradient elution of methanol and 0.1% formic acid, and mass‐to‐charge ratios were determined in selective reaction monitoring mode using tandem mass spectrometry with m/z 343.12 > 296.97 for homoegonol and m/z 517.30 > 282.90 for udenafil (internal standard). The standard curve was linear over the concentration ranges of 1 ? 500 ng/mL using a 30 μL rat plasma sample. The coefficient of variation and relative error for intra‐ and inter‐assay at four quality control levels were 3.9–10.0 and ‐3.3–2.7%, respectively. The overall recovery of homoegonol from rat plasma using protein precipitation was 99.7 ± 7.7%. The pharmacokinetics parameters of homoegonol were dose‐independent after both intravenous (1, 2.5 and 5 mg/kg doses) and oral (5, 10 and 20 mg/kg doses) administration in male Sprague–Dawley rats. Copyright © 2014 John Wiley & Sons, Ltd.     

Determination of rabeprazole enantiomers in dog plasma by supercritical fluid chromatography tandem mass spectrometry and its application to a pharmacokinetic study

Rabeprazole is a novel benzimidazole proton pump inhibitor used for the treatment of gastrointestinal disorders. It is a chiral molecule that gives rise to the possibility of stereoselective pharmacokinetics. To investigate this phenomenon, a rapid and sensitive chiral assay based on supercritical fluid chromatography tandem mass spectrometry was developed and applied to the determination of (R )‐rabeprazole and (S )‐rabeprazole in dog plasma. Sample preparation involved protein precipitation with acetonitrile after the addition of (R )‐lansoprazole as internal standard. Baseline separation of enantiomers in 4.5 min was achieved on an Acquity UPC² system using an ACQUITY UPC² Trefoil CEL2 column maintained at 60°C and a mobile phase consisting of methanol/CO₂ (30:70, v/v) delivered at 2.5 mL/min. Detection was achieved by multiple reaction monitoring of the transitions at m/z 360.0→242.2 (rabeprazole) and 370.3→252.0 (internal standard) in the positive ion mode. The assay was linear in the range of 1–1000 ng/mL and free of matrix effects. Intra‐ and interday precisions were less than 10.0% with accuracy in the range of –2.6 to 3.1%. The method was successfully applied to a pharmacokinetic study of rabeprazole enantiomers after administration of a single oral dose of 10 mg racemate to beagle dogs.     

A validated LC–MS/MS method for the quantification of capivasertib in dog plasma: Application to its pharmacokinetics study

In this study, a simple and reliable liquid chromatography tandem mass spectrometric method was first developed for the determination of capivasertib in dog plasma with ipatasertib as internal standard. The plasma samples were deproteinated using acetonitrile. An Acquity BEH C₁₈ column (1.7 μm, 2.1 × 50 mm) maintained at 40°C was used for chromatographical separation, with water containing 0.1% formic acid and acetonitrile as mobile phase. Multiple reaction monitoring transitions were m/z 429.2 > 135.1 for capivasertib and m/z 458.2 > 387.2 for ipatasertib, respectively. Excellent linearity was achieved in the concentration range of 1–1,000 ng/ml with a correlation coefficient of >0.9981. The lower limit of quantification was 1 ng/ml. The extraction recovery of capivasertib from dog plasma was >85.81% and no significant matrix effect was found. The intra- and inter-day precision was <9.58% and the accuracy ranged from −10.60% to 12.50%. The validated method was further applied to the pharmacokinetic study of capivasertib in dog plasma after single oral (5 mg/kg) and intravenous (1 mg/kg) administrations. The results revealed that capivasertib was rapidly absorbed into plasma with good bioavailability (47.04%) and low clearance.     

Determination of lansoprazole enantiomers in dog plasma by column‐switching liquid chromatography with tandem mass spectrometry and its application to a preclinical pharmacokinetic study

Lansoprazole, a selective proton pump inhibitor, has a chiral benzimidazole sulfoxide structure and is used for the treatment of gastric acid hypersecretory related diseases. To investigate its stereoselective pharmacokinetics, a column‐switching liquid chromatography with tandem mass spectrometry method was developed for the determination of lansoprazole enantiomers in dog plasma using (+)‐pantoprazole as an internal standard. After a simple protein precipitation procedure with acetonitrile, matrix components left behind after sample preparation were further eliminated from the sample by reversed‐phase chromatography on a C₁₈ column. The fluent was fed to a chiral column for the separation of lansoprazole enantiomers. Baseline separation of lansoprazole enantiomers was achieved on a Chiralcel OZ‐RH column using acetonitrile/0.1% formic acid in water (35:65, v/v) as the mobile phase at 40°C. The linearity of the calibration curves ranged from 3 to 800 ng/mL for each enantiomer. Intra‐ and inter‐day precisions ranged from 2.1 to 7.3% with an accuracy of ±1.7% for (+)‐lansoprazole, and from 1.6 to 6.9% with an accuracy of ±3.5% for (–)‐lansoprazole, respectively. The validated method was successfully applied for the stereoselective pharmacokinetic study of lansoprazole in beagle dog after intravenous infusion.     

Simultaneous determination of atractylenolide II and atractylenolide III by liquid chromatography-tandem mass spectrometry in rat plasma and its application in a pharmacokinetic study after oral administration of Atractylodes Macrocephala Rhizoma extract

Atractylenolide II (AII) and atractylenolide III (AIII) are the major active components in Atractylodes Macrocephala Rhizoma (AMR). In this study, a sensitive, rapid and selective liquid chromatography–tandem mass spectrometry (LC‐MS/MS) method was developed and validated for the simultaneous determination of AII and AIII in rat plasma using loliolide as internal standard (IS). After protein precipitation with ethyl acetate, the analytes were injected into an LC‐MS/MS system for quantification. Chromatography was performed using a C₁₈ column, eluting with water and acetonitrile (45:55, v/v) at 0.2 mL/min. All analytes including IS were monitored under positive ionization conditions by multiple reaction monitoring with an electrospray ionization source. The validated method was successfully applied to the pharmacokinetic study of AII and AIII in rat plasma after oral administration of AMR extract. The results provided a meaningful basis for evaluating the clinical applications of traditional Chinese medicine. Copyright © 2012 John Wiley & Sons, Ltd.     

Determination of ipriflavone in human plasma by LC-MS and its application in a pharmacokinetic study

A sensitive liquid chromatography-mass spectrometric method was developed for the quantification of ipriflavone in human plasma. The method utilized liquid-liquid extraction of plasma with ethyl acetate. A gradient elution was performed on a Hedera ODS-2 column (150×2.1 mm i.d., 5 μm), using a mobile phase consisting of 0.1% formic acid solution and methanol at a flow rate of 0.5 mL/min. The single quadrupole mass spectrometer was operated in selected-ion monitoring mode via positive electrospray ionization interface detecting m/z 239.1 and 285.1 for ipriflavone and diazepam (the internal standard), respectively. To improve the selectivity and sensitivity, the fragment ion m/z 239.1, which was produced by in-source collision-induced dissociation, was chosen as the quantitative ion for ipriflavone. The method was fully validated and applied to a pharmacokinetic study of ipriflavone. After oral administration of a single 200 mg ipriflavone tablet, the C(max,) AUC(0-72 h) , t(1/2) and T(max) were 6.3±6.3 ng/mL, 80.0±69.1 μg h/L, 23.0±8.6 h and 3.4±2.1 h, respectively.     

Determination of paeonol in rat plasma by high-performance liquid chromatography and its application to pharmacokinetic studies following oral administration of Moutan cortex decoction

Quantification of paeonol, the principal bioactive component of Moutan cortex, in rat plasma following oral administration of Moutan cortex decoction was achieved by using a simple and sensitive high-performance liquid chromatographic method. The calibration curves for paeonol were linear in both the low (25-200 ng/mL) and the high concentration range (200-4000 ng/mL) with r(2) values of 0.9928 and 0.9993, respectively. The coefficients of variation of intra- and inter-day assays were 14.36, 6.52, 1.76, 1.25, 5.36, 3.30 and 1.42% and 12.70, 1.19, 2.98, 1.91, 1.75, 1.78 and 0.96% at concentrations of 25, 50, 100, 200, 500, 1000 and 2000 ng/mL, respectively. The recoveries of paeonol from rat plasma were found to be 101.9, 104.5, 105.4 and 101.2% for concentrations of 50, 500, 1000 and 2000 ng/mL, respectively. The paeonol plasma concentrations were fitted to two-compartment model with fi rst order absorption. The mean terminal half-lives (t(1/2)) of paeonol was 80.9 min.     

HPLC determination of diltiazem in human plasma and its application to pharmacokinetics in humans

A simple and sensitive reversed-phase high performance liquid chromatographic method (HPLC) has been developed and validated for the routine analysis of diltiazem in human plasma and the study of the pharmacokinetics of the drug in the human body. Diltiazem and diazepa (internal standard) were extracted with a mixed organic solution of hexane, chloroform and isopropanol (60:40:5, v/v/v), and then HPLC separation of the drugs was performed on an Spherisorb C(18) column and detected by ultraviolet absorbance at 239 nm. The use of methanol-water solution (containing 2.8 mm triethylamine, 80:20, v/v) as the mobile phase at a fl ow-rate of 1.2 mL/min enables the baseline separation of the drugs free from interferences with isocratic elution. The method was linear in the clinical range 0-300 ng/mL and the lower limit of detection of diltiazem in plasma was 3 ng/mL. The range of percentage of relative standard deviation (%RSD) was from 3.5 to 6.8% for within-day analyses and from 6.2 to 8.4% for between-day analyses, respectively. The extraction recoveries of diltiazem from spiked human plasma (n = 5) at three concentrations were 91.4-104.0%. The method has been used to determine diltiazem in human plasma samples from eight volunteers who had taken diltiazem hydrochloride slow release tables and the data obtained was fitted with a program on computer to study the pharmacokinetics. The results showed that the peak level in plasma approximately averaged 118.5 +/- 14.3 ng/mL at 3.1 +/- 0.4 h, and the areas under the drug concentration curves (AUC) was 793.1 +/- 83.1 ng.h/mL.     

A solid-phase extraction method for high-performance liquid chromatographic determination of salvianolic acid B in rabbit plasma: application to pharmacokinetic study

A sensitive solid-phase extraction/high-performance liquid chromatographic method with ultraviolet detection was established for the analysis of salvianolic acid B in rabbit plasma. The analyte was separated on a reversed-phase column with trifluoroacetic acid-methanol-acetonitrile (70:10:20, v/v/v) as mobile phase at a flow rate of 1 mL/min, and ultraviolet detection at 315 nm. The calibration curve for salvianolic acid B was linear over the range 35-1400 microg/L with coefficients of correlation >0.999. The inter-day and intra-day precisions of analysis were <15%, and assay accuracy ranged from 95.3 to 109.1%. This method is suitable for determining salvianolic acid B in plasma and thus investigating the pharmacokinetics of salvianolic acid B.