Extraction and RP-HPLC determination of taxol in rat plasma, cell culture and quality control samples

A rapid, sensitive, selective and validated reverse phase high-performance liquid chromatography （RP-HPLC） method for the estimation of paclitaxel in micro-sample of rat plasma and in culture of cancer cells was per- formed in this study. The mobile phase consisted of an （80： 20： 0.1, v/v/v）. Column elution at a flow rate of 1 optimized mixture of methanol：water： trifluroacetic acid mL/minute with UV detection at 225 nm at room tern- perature was used. The RP-HPLC method was successfully applied for the determination of paclitaxel in plasma samples and in culture of cancer cells with nano-quantity of estimation. The validation studies were performed in accordance with the International Conference on Harmonization （ICH） guidelines. The intra- and inter-day pre- cision showed that the coefficients of variation ranged from 1.07% to 4.27% at different levels of concentrations. To the best of our knowledge, this study also reported for the first time the optimization of different solvents for effective extraction of paclitaxel wherein tert.-butyl methyl ether （TBME）： diethyl ether （DEE） in 50：50 v/ v composition was found most efficient with extraction efficiency ranging between 77.99% and 91.74% and be- tween 76.14 and 93.66% in the plasma and cell culture, respectively. This proposed method was successfully ap- plied to study the pharmacokinetics of paclitaxel and the influence of verapamil and all-trans retinoic acid （atRA） on paclitaxel pharmacokinetics in rat models. This proposed method might emerge as a valuable aid in the labo- ratory monitoring of paclitaxel in a variety of in vitro as well as in vivo scenarios.

Validation of HPLC and FIA Spectrophotometric Methods for the Determination of Lansoprazole in Pharmaceutical Dosage Forms and Human Plasma

A chromatographic and aspectrophotometric methods for the quantitative determination of lansoprazole in pharmaceutical combinations and human plasma were developed. The analytical parameters were studied according to International Conference on Harmonization guidelines. The Flow Injection Analysis (FIA) method is based on the oxidation of lansoprazole by a known excess of N-bromosuccinimide (NBS) in an acidic medium, followed by a reaction of excess oxidant with chloranilic acid (CAA) to bleach its purple color. The separation was carried out using RP-C18 column with a mobile phase composed of ACN: TEA: phosphate buffer (60: 0.2: 39.8 v/v) adjusted to pH = 4.

Determination of 5-Fluorouracil in Human Plasma by High-Performance Liquid Chromatography (HPLC)

5-Fluorouracil (5-FU) has a broad spectrum of anti-tumor activity, widely applied to the treatment of cancers. However, it is necessary to determine the plasma concentration of 5-FU in clinical practice due to its narrow therapeutic index. Therefore, a simple, economic and sensitive high-performance liquid chromatography (HPLC) method was developed and validated for the determination of 5-FU in human plasma. Ethyl acetate was chosen as extraction reagent. Chromatographic separation was performed on a Diamonsil C18 column (250 mm × 4.6 mm i.d., 5 μm) with the mobile phase consisting of methanol and 20 mmol/L ammonium formate using a linear gradient elution at a flow rate of 0.8 mL/min. 5-FU and 5-bromouracil (5-BU) were detected by UV detector at 265 nm. The calibration curve was linear over the concentration range of 5—500 ng/mL and the correlation coefficient was not less than 0.992 6 for all calibration curves. The intra- and inter-day precisions were less than 10.5% and 4.3%, respectively, and the accuracy was within ±3.7%. The recovery at all concentration levels was 80.1±8.6%. 5-FU was stable under possible conditions of storing and handling. This method is proved applicable to therapeutic drug monitoring and pharmacokinetic studies of 5-FU in human.

Development of RP-HPLC method for simultaneous determination of docetaxel and curcumin in rat plasma: Validation and stability

The purpose of the present research was to develop a suitable, simple, precise, accurate,robust, and reproducible RP-HPLC method for a reliable simultaneous quantification of docetaxel(DTX) and curcumin(CCM) in rat plasma samples using paclitaxel(PTX) as an internal standard. The samples were assayed by the Agilent 1260 Infinity HPLC instrument using a Capcell Pak C8 column(4.6 mm × 150 mm, 5 μm) under isocratic conditions. The mobile phase consisted of acetonitrile and triple distilled water(40/60, v/v) with a flow rate of 1.0 ml/min. The eluent was monitored at 230 nm for simultaneous measurement of curcumin and docetaxel. The method was validated by determining system suitability, selectivity, sensitivity, linearity, inter-day and intra-day precision, accuracy, robustness, and stability in accordance with the guidelines of the United States Food and Drug Administration(FDA).The developed chromatographic method proved to be simple, precise, accurate, robust and reproducible. Moreover, the samples showed stability at room temperature over a period of 48 h. Thus, this method would be employed for routine simultaneous quantification of docetaxel and curcumin in rat plasma samples.

Simultaneous determination of doxorubicin and its dipeptide prodrug in mice plasma by HPLC with fluorescence detection

A simple and sensitive high performance liquid chromatography with fluorescence detection （HPLC-FD） has been developed for simultaneous quantification of doxorubicin （DOX） and its dipeptide conjugate prodrug （PDOX） in mice plasma. The chromatographic separation was carried out on an Amethyst C18-H column with gradient mobile phase of 0.1% formic acid and 0.1% formic acid in acetonitrile at a flow rate of 1.0 mL/min. The excitation and emission wavelengths were set at 490 and 550 nm, respectively. The method was comprehensively validated. The limits of detection were low up to 5.0 ng/mL for DOX and 25.0 ng/mL for PDOX. And the limits of quantification were low up to 12.5 ng/mL for DOX and 50 ng/mL for PDOX, which were lower than those for most of the current methods. The calibration curves showed good linearity （R2 〉 0.999） over the concentration ranges. The extraction recoveries ranged from 84.0% to 88.2% for DOX and from 85.4% to 89.2% for PDOX. Satisfactory intra-day and inter-day precisions were achieved with RSDs less than 9.1%. The results show that the developed HPLC-FD method is accurate, reliable and will be helpful for preclinical pharmacokinetic study of DOX and PDOX.

Simultaneous determination of metronidazole and tinidazole in plasma by using HPLC-DAD coupled with second-order calibration

A method using HPLC-DAD coupled with second-order calibration was developed to simultaneously determine metronidazole and tinidazole in plasma samples in this paper. The second-order calibration method based on APTLD （alternating penalty trilinear decomposition） algorithm was proposed to analyze the three-way HPLC-DAD data from both standard and prediction samples, which makes it possible that calibration can be performed even in the presence of unknown interferences with a simple and green chromatographic condition and short analysis time. The results showed that good recoveries were obtained although the chromatographic and spectral profiles of the analytes of interest as well as background were partially overlapped with each other in plasma samples.

Determination of fenticonazole in human plasma by HPLC–MS/MS and its application to pharmacokinetic studies

Two simple and sensitive high performance liquid chromatography–tandem mass spectrometry(HPLC–MS/MS) methods were developed and validated for the determination of fenticonazole in human plasma after percutaneous and intravaginal administration. Mifepristone was used as an internal standard(IS), and simple protein precipitation by acetonitrile containing 2% acetic acid was utilized for extracting the analytes from the plasma samples. Chromatographic separation was performed on a Kinetex XB-C_(18) column. The quantitation was performed by a mass spectrometer equipped with an electrospray ionization source in multiple reactions monitoring(MRM) positive ion mode using precursor-to-product ion transitions of m/z 455.2–199.1 for fenticonazole and m/z 430.2–372.3 for mifepristone. The validated linear ranges of fenticonazole were 5–1000 pg/m L and 0.1–20 ng/m L in plasma for the methods A and B, respectively. For the two methods, the accuracy data ranged from 85% to 115%, the intra- and inter-batch precision data were less than 15%, the recovery data were more than 90%, and no matrix interference was observed. The methods A and B were successfully validated and applied to the pharmacokinetic studies of fenticonazole gel in Chinese healthy volunteers after percutaneous and intravaginal administration, respectively.

Determination and pharmacokinetic study of catechin in rat plasma by HPLC

A high performance liquid chromatographic method was developed and validated for the quantitative determination of catechin in rat plasma and its pharmacokinetic study after intragastric administration of Catechu and Xiongdanjiangre Wan into SD rats. Plasma samples were prepared by protein precipitation using methanol-5% aqueous zinc sulfate （70：30, v/v） as precipitant. Chromatographic separation was achieved on Hypersil Cl8 column （250 mm~ 4.6 mm, 10 pm） with acetonitrile-water-triethylamine （6：94：0.3, v/v/v, pH 4.0＋0.1, adjusted with phos- phoric acid） as mobile phase, followed by a UV detection at 207 nm. Good linearity was obtained over the range of 0.143-7.15 mg/L of catechin, with correlation coefficient of 0.9992. The method was simple, sensitive, accurate and reproducible and＇ has been successfully applied to the pharmacokinetic study of catechin in rat plasma.

An Ion-Pair HPLC Method for Simultaneous Determination of Exogenous Phosphocreatine and Its Metabolite Creatine and Related ATP in Rabbit Plasma and RBC: Application to a Pharmacokinetic Study

A specific, precise and accurate ion-pair HPLC-UV method has been developed and validated for simultaneous determination of phosphocreatine (PCr), and its metabolite creatine (Cr) as well as related ATP in plasma and red blood cell (RBC) of rabbits. After addition of TMP as IS, the samples were deproteinized with 6% PCA. The analytes were separated on a Kromasil C18 column using a tertiary gradient mobile phase composed of buffer A (0.2% KH2PO4 + 0.08% tetrabutyl ammonium hydrogen sulphate, pH 3.0), buffer B (buffer A adjusted to pH 7.5 with 1 mol/L NaOH) and MeOH. Detection wavelengths were set at 210 nm for PCr and Cr and 260 nm for ATP and TMP. Some blank samples were initially run for baseline subtraction. The linear detection responses were obtained for PCr concentration over a range of 10 - 7500 mg/ml (plasma) and 5 - 2500 mg/ml (RBC) and for both Cr and ATP concentrations of 10 - 1500 mg/ml (plasma) and 5 - 750 mg/ml (RBC) (r > 0.99). The QC samples of 3 analytes showed intra-day and inter-day precisions (RSD) of - 107%. The method was successfully used to simultaneously determine plasma and RBC concentrations of the 3 analytes and to study pharmacokinetics after iv administration of PCr to rabbits.

Optimization and validation of a fast RP-HPLC method for the determination of dobutamine in rat plasma:Pharmacokinetic studies in healthy rat subjects

A novel isocratic reverse phase high performance liquid chromatography （RP-HPLC） with photo diode array （PDA） detection method for the determination of dobutamine （DBT） in rat plasma was developed and validated after optimization of various chromatographic conditions and other experimental parameters. Homoveratrylamiue was used as an internal standard. Methanol was used as the extracting solvent for the preparation of plasma samples. Samples were separated on a Symmetry C18 （250ram x4.6mm i.d., 5 pro） analytical column. Acetonitrile and 15raM potassium dihydrogen phosphate （pH 5.0 with 0.3% TEA） （20：80, v/v） was used. The column oven temperature was optimized at 35 ~C and the flow rate was 0.8 mL/min. The detection wavelength was fixed at 230 nm for entire analysis. The calibration curve was found to be linear over the concentration range of 50-2000 ng/mL （ra=0.9992）. The limit of quantification （LOQ） of the method was 50 ng/mL. The % RSD values of accuracy and precision values for intra and inter days were 〈 15% at quality control （QC） concentrations. Recovery, stability and robustness were studied within the acceptable range according to ICH guidelines. The method was efficiently applied to a pharmacokinetic study in healthy Wistar rats.

A sensitive, simple and rapid HPLC–MS/MS method for simultaneous quantification of buprenorpine and its N-dealkylated metabolite norbuprenorphine in human plasma

A sensitive, simple and rapid high performance liquid chromatography-tandem mass spectrometry （HPLC-MS/MS） method was developed and fully validated for the simultaneous quantification of buprenorphine （BUP） and its N-dealkylated metabolite norbuprenorphine （NBUP） in 200 μL human plasma. Human plasma samples were prepared using liquid-liquid extraction, and then separated on a Shiseido MG C18 （5 μm, 2.0 mm × 50 mm） via 4.1 min gradient elution. Following electrospray ionization, the analytes were quantified on a triple-quadrupole mass spectrometer in multiple-reaction-monitoring （MRM） positive ion mode. Linearity was achieved from 25.0 to 10000 pg/mL for buprenorphine, from 20.0 to 8000 pg/mL for norbupre- norphine with r2〉0.99. The method was demonstrated with acceptable accuracy, precision and specificity for the detection of buprenorphine and norbuprenorphine. Recovery was 81.8-88.8 % for buprenorphine and 77.0-84.6% for norbuprenorphine, and the matrix effect was 95.6-97.4% for buprenorphine and 94.0-96.9% for norbuprenorphine; all were not concentration dependent. With validated matrix and autosampler stability data, this method was successfully applied in a bioequivalence study to support abbreviated new drug application.

Determination of Sibutramine and Its <i>N</i>-Desmethyl Metabolites in Human Plasma Using HPLC Coupled with Tandem Mass Spectroscopy

The following article has been retracted due to the investigation of complaints received against it. The Editorial Board found that there are conflicts of interests between the authors and their organization. The scientific community takes a very strong view on this matter, and the American Journal of Analytical Chemistry treats all unethical behavior seriously. This paper published in Vol. 5 No. 9 589-597, 2014 has been removed from this site. Title: Determination of Sibutramine and Its N-Desmethyl Metabolites in Human Plasma Using HPLC Coupled with Tandem Mass Author: Mohammad

RP-HPLC法测定人血中伏立康唑血药浓度

目的建立一种快速、简便、准确的RP-HPLC法测定人血中伏立康唑血药浓度的方法,以便于监测伏立康唑的血药浓度,指导患者个体化治疗。方法采用2倍体积乙腈沉淀血浆蛋白,采用RP-HPLC法,以卡马西平为内标,色谱条件如下:色谱柱为Agilent TC-C_(18)(4.6 mm×250 mm,5μm),流动相为乙腈-水(40∶60,V/V),流速1.0 ml·min^(-1),紫外检测波长为255 nm,进样量10μl。结果伏立康唑与卡马西平的保留时间分别为10.1和6.52 min。伏立康唑在0.2256~22.56μg·ml^(-1)范围内线性关系良好(r=0.9998);定量下限为0.2256μg·ml^(-1);相对标准偏差分别批内≤4.30%,批间≤3.94%;伏立康唑高、中、低三个浓度的绝对回收率为80.51%~95.44%。结论该方法灵敏度高,操作简便,结果准确,检测成本低,更适用于临床实践中常规的伏立康唑血药浓度监测及基础药代动力学研究。

HPLC-MS/MS法考察水黄皮素在SD大鼠体内的药代动力学特征

目的:建立大鼠血浆中水黄皮素的定量分析方法,并对其药代动力学进行研究。方法:通过灌胃给予SD大鼠水黄皮素(10 mg·kg^(-1)),血浆样品经蛋白沉淀法处理后进行HPLC-MS/MS定量分析,以五味子醇甲为内标,采用Agilent Poroshell 120 EC-C_(18)(50 mm×3.0 mm,2.7μm)色谱柱,乙腈(A)-0.1%甲酸溶液(B)为流动相,流速0.3 mL·min^(-1),梯度洗脱;采用电喷雾离子源(ESI),正离子多反应监测模式(MRM)扫描,水黄皮素[M+H]^(+)m/z 293.1→277.0,五味子醇甲[M+H]^(+)m/z433.2→384.2;使用DAS软件计算相关药代动力学参数。结果:在1.5625~1600 ng·mL^(-1)浓度范围内,水黄皮素线性关系良好(r=0.9997),定量下限为1.5625 ng·mL^(-1),精密度RSD和准确度RE均小于20%;低、中、高质控样品精密度RSD和准确度RE均小于15%,提取回收率在91.70%~100.28%,基质效应在88.35%~97.55%,稳定性RSD均小于15%。水黄皮素在雌性SD大鼠体内T_(max)、t_(1/2)、C_(max)和AUC_(0→t)分别为3 h、1.95 h、1214.85 ng·mL^(-1)和11920.43 ng·mL^(-1)·h;在雄性SD大鼠体内T_(max)、t_(1/2)、C_(max)和AUC_(0→t)分别为3 h、1.19 h、1221.57 ng·mL^(-1)和9983.40 ng·mL^(-1)·h。结论:所建方法符合生物样品定量分析的基本要求,可用于水黄皮素在大鼠血浆中的含量测定及其药代动力学评价;水黄皮素在雌性SD大鼠体内的生物利用度更高。

HPLC-MS/MS法测定人血浆丙戊酸浓度的不确定度评定

目的对HPLC-MS/MS法测定人血浆中丙戊酸浓度的不确定度进行评定与分析。方法测定人血浆中丙戊酸浓度,用A类评定评价重复性测量引入的不确定度,用B类评定对对照品称量、对照品纯度、溶液配制、含药血浆配制、提取回收率、基质效应、标准曲线拟合和仪器测定引入的不确定度进行评定,并计算合成和扩展不确定度。结果当P=95%置信概率(k=2)时,人血浆中低(1200 ng/mL)、中(12000 ng/mL)、高(75000 ng/mL)质量浓度丙戊酸的扩展不确定度分别为345.09、589.73、2789.74 ng/mL。结论方法准确度高,适用于丙戊酸的药动学研究和血药浓度监测。不确定度主要来源于标准曲线拟合、基质效应和提取回收率,低浓度时标准曲线拟合引入的不确定度值较中、高浓度的高。设定合理的线性范围、优化提取方式和色谱条件等可提高测定结果准确性。

Development and validation of an RP-HPLC-UV method for the determination of daphnoretin in rat plasma

A sensitive RP-HPLC-UV method has been developed and validated for the quantification of daphnoretin in rat plasma. Daphnoretin was extracted from rat plasma by protein precipitation and liquid-liquid extraction. Separation was performed on a Diamonsil C18 column （200 mm× 4.6 mm, 5 μm） with a mobile phase of methanol-20 mmol/L ammonium acetate （adjusted to pH 3.2 with acetic acid, 42：58, v/v） at a flow rate of 1.0 mL/min. The UV detector was set at 345 nm and column temperature was set at 40 ℃. The calibration curves were linear over the concentration range of 0.020-2.00 ~tg/mL, The lower limit of quantification （LLOQ） of daphnoretin in rat plasma was 0.020 μg/mL. The intra- and inter-day relative standard deviation （RSD） for measurement of quality control （QC） samples （0.050, 0.200 and 1.60 μg/mL） ranged from 5.0%-10.6%. Relative error （RE） was from ±（1.2%-2.5%）. The validated method was used successfully in a pharmacokinetic study of daphnoretin in rats after intraperitoneal injection.

Chiral separation of bavachinin in Fructus Psoraleae and rat plasma by liquid chromatography using permethylated-b-CD as a chiral selector

A simple, sensitive and selective method of high-performance liquid chromatography （HPLC） has been successfully developed for separation of bavachinin enantiomers in Fructus Psoraleae and rat plasma. The separation and detection conditions of HPLC were optimized. Chiral bavachinin were separated with the mobile phase of methanol and water （70：30, v/v） at a flow rate of 1.0 mL/min. The linear ranges were in the range of 20-1000 μg/mL. The detection limits were tested as 4 ng/mL and 6 ng/mL for （＋）-bavachinin and （-）-bavachinin, respectively. The method has been applied to analyze chiral bavachinin in rat plasma. HPLC-MS method was used to test the accuracy.

RP-HPLC测定人血浆中洛伐他汀浓度及药动学研究

用ＲＰ－ＨＰＬＣ测定人血浆中洛伐他汀浓度。以甲醇－水（８３∶１７，Ｖ／Ｖ）为流动相，色谱柱采用ＨＹＰＥＲＳＩＬＢＤＳ－Ｃ１８（５μｍ）不锈钢柱，紫外２３７ｎｍ波长检测。血浆样品经环己烷－异丙醇（９５∶５）萃取浓缩后进样测定。洛伐他汀浓度在２．５～８０ｎｇ／ｍｌ范围内线性良好，ｒ＝０．９９６８。测定含洛伐他汀２０．０ｎｇ／ｍｌ的血浆样品，其日内（ｎ＝７）及日间（ｎ＝７）的ＲＳＤ分别为９．８％和８．５％。回收率平均为（１０１．３±５．５）％。测定了１０名健康志愿者单次ｐｏ洛伐他汀片剂８０ｍｇ后不同时间的血药浓度，计算了相应的药动学参数。

Quantitative determination of ganoderic acid T in rat plasma by a sensitive RP-HPLC method and its application in pharmacokinetic studies

A selective and sensitive HPLC method has been developed and validated for the quantification of ganoderic acid T in rat plasma. A reverse-phase column was used with UV detection at 245 nm. The mobile phase consisted of methanol-water-acetic acid （95.5：4.5：0.5, v/v/v） run at a flow rate of 1 mL/min. Testosterone propionate was used as the internal standard. The standard curve was linear over the range of 0.05-50 ~tg/mL in rat plasma with a linear correlation coefficient greater than 0.999. The lower limit of quantification of this assay was 20 ng/mL. The recoveries of samples at 0.05, 2 and 40 μg/mL were 97.6%, 98.4% and 103.2%, respectively. The relative standard deviations of intra- and inter-day assay variations were less than 8.2%. The usefulness of the assay was confirmed by the successful analysis of plasma samples from a pharmacokinetics study in rats. Following a single dose of ganoderic acid T （5 mg/kg for i.v. or 14 mg/kg for p.o.）, the main pharmacokinetic parameters by intravenous injection were： t1/2α （5.46±1.25） min; t1/2β：（227.18±11.40） min; CL： （1.09±0.16） mL/（kg·min）; A UC0-12 h： （3939.13±311.14） μg.min/mL; AUC0-12h （4681.96±710.70）μg.min/mL and the absolute bioavailability was 41.98%±2.40%. This method is simple, sensitive, and accurate. It is suitable for pharmacokinetic studies of ganoderic acid in rats.

Simultaneous determination of ginsenosides Rg_1,Re and Rb_1 in rat plasma by HPLC and its application to pharmacokinetic study of SHENMAI injection

In the present study, we developed a sensitive and efficient high performance liquid chromatography （HPLC） method for the simultaneous determination of three ginsenosides （Rg1, Re, Rb1） in rat plasma. Chromatographic separation was performed on a C18 （150 min×4.6 mm） column utilizing gradient elution profile and a mobile phase consisting of （A） water and （B） acetonitrile. The calibration curve, with a great correlation coefficient greater than 0.998, was linear over the range of 1.0-30.0 μg/mL for ginsenoside Rgl, 0.5-15.0 μg/mL for ginsenoside Re, and 0.5-200.0 μg/mL for ginsenoside Rb1. The intra- and inter-day precisions for three ginsenosides （Rg1, Re, Rb1） were all less than 6.0%, and average recovery, examined at three concentration levels, ranged from 96.1% to 118.6%. The samples was stable within 24 h at 4 ℃ storage, and 30 d at -20 ℃ storage with three freeze-thaw-assay cycles. The low limits of quantification （LOQ） were 1.0, 0.5 and 0.5 μg/mL for Rg1, Re and Rb1, respectively. Taken together, the newly developed method was successfully applied to study the pharmacokinetics of ginsenoside Rg1, Re and Rb1 in rat plasma after intravenous administration of SHENMAI injection （SMI）.