Determination of atrasentan by high performance liquid chromatography with fluorescence detection in human plasma.

Atrasentan is an endothelin antagonist selective for the ET(A) receptor in development at Abbott Laboratories for the treatment of cardiovascular disease and cell proliferation disorders. A simple and sensitive chromatographic method for the determination of atrasentan in human plasma has been developed and validated. The analytical method involves acidification of the plasma samples with 0.3 N HCl prior to extraction with 1:1 (v:v) hexane/tert-butylmethylether. The organic extract was evaporated to dryness, reconstituted with 20:80 (v:v) acetonitrile/0.05 M K(2)HPO(4) and washed with 75:25 (v:v) hexane/tert-butylmethylether. The organic layer was discarded and the aqueous layer was injected into the HPLC. Atrasentan and internal standard (ABT-790) were separated from interference using a 250 x 4.6 mm, 5 microm, 120 A Phenomenex Spherisorb C(8) analytical column with a 50 x 4.6 mm, Alltech Absorbosphere 5 microm CN guard cartridge using a mobile phase consisting of 25:15:5:55 (v:v:v:v) acetonitrile/isopropanol/methanol/0.05 M K(2)HPO(4), pH 7.0, at a flow rate of 1.0 mL/min. Fluorescence detection was achieved using lambda(ex) 278 nm and lambda(em) 322 nm. For a 1.0 mL plasma sample volume, the limit of quantitation was approximately 200 pg/mL. The method was linear from 0.2 to 1300 ng/mL (r(2) = 0.9986). Inter- and intra-day assay RSD (n = 6) were less than 10%. Mean accuracy determinations showed the quality control samples to range between 94 and 99% of the theoretical concentration.     

反相高效液相色谱法测定血浆中的单硝酸异山梨酯

建立了反相高效液相色谱测定血浆中单硝酸异山梨酯浓度的方法。样品在碱性条件下经二氯甲烷提取后,用C18柱进行分离,以H2O(用0.03 mol/L氨水调pH至7.8)-乙腈(体积比为80∶20)为流动相,对乙酰氨基酚为内标,于230 nm处测定。结果表明,单硝酸异山梨酯的质量浓度为20~1000 μg/L时其峰面积与内标峰面积之比与单硝酸异山梨酯浓度有良好的线性关系。方法的最低检测质量浓度为12 μg/L,平均回收率为(97.11±2.45)％~(104.34±2.17)%,日内测定的相对标准偏差(RSD)≤2.52%,日间测定的RSD≤5.21%。     

High performance liquid chromatographic method for the determination and pharmacokinetic studies of oxyresveratrol and resveratrol in rat plasma after oral administration of Smilax china extract

A sensitive and simple HPLC method has been developed and validated for the determination of oxyresveratrol (trans-2,4,3',5'-tetrahydroxystilbene, OXY) and resveratrol (trans-3,5,4'-trihydroxystilbene, RES) in rat plasma. The plasma samples were extracted with ethyl acetate and analyzed using HPLC on an Aglient Zorbax SB-C(18) column (250 x 4.6 mm, 5 microm) at a wavelength 320 nm, with a linear gradient of (A) acetonitrile and (B) 0.5% aqueous acetic acid (v/v), at a flow rate of 1.0 mL/min. The method was linear over the range of 0.1265-25.3 microg/mL for OXY and 0.117-23.4 microg/mL for RES. The extraction recovery for OXY, RES and internal standard ranged from 71.1 to 88.3%. The intra- and inter-day precisions were better than 10%, and the accuracy ranged from 89 to 108%. The validated method was used to study the pharmacokinetic profiles of OXY and RES in rat plasma after oral administration of Smilax china root extract.     

柱切换技术-高效液相色谱法快速检测大鼠血浆中的普萘洛尔对映体

建立了快速检测大鼠血浆中普萘洛尔对映体浓度的柱切换-高效液相色谱法。将自制限进填料柱作为预处理柱,通过直接进样方式,使普萘洛尔对映体在预处理柱上保留,同时除去血浆中的蛋白质等大分子;再通过柱切换技术,使普萘洛尔对映体在键合型纤维素-三(3,5-二甲基苯基氨基甲酸酯)(Chiralcel OD-RH)分析柱上得到手性拆分。通过条件优化,确定切换前预处理流动相为硼酸盐缓冲液(pH 8.5)-甲醇(95:5, v/v),流速为1.0 mL/min;切换后分析流动相为异丙醇-乙醇-0.2 mmol/L硼酸盐缓冲液(pH 8.5)(30:30:40, v/v/v),流速为0.8 mL/min;切换时间为3 min;柱温为25 ℃;检测波长为293 nm。普萘洛尔两对映体在25～500 mg/L的质量浓度范围内具有良好的线性关系(r=0.9995), 3个加标水平(50、100、250 mg/L)的平均回收率为97.89%～101.56%,日内和日间精密度均小于5%。该方法简便、快速、灵敏、准确,适于血浆样本中手性药物的药代动力学研究。     

手性试剂柱前衍生化高效液相色谱法测定α-苯乙胺的光学纯度

建立了一种简便的手性试剂柱前衍生化反相高效液相色谱测定α-苯乙胺光学纯度的方法。采用2,3,4,6-四-O-β-D-吡喃葡萄糖异氰酸酯(GITC)对α-苯乙胺进行衍生化,优化了衍生化反应参数;使用Agilent Zorbax C18色谱柱分离衍生化产物,流动相为甲醇-磷酸盐缓冲溶液(pH 3.0)(体积比为58:42),流速1.0 mL/min,检测波长241 nm,柱温为30 ℃。实验结果表明,α-苯乙胺两个对映体的衍生化产物分离良好,在0.15～15.0 mg/L范围内呈现良好的线性关系。方法的检出限为0.05 mg/L,定量限为0.15 mg/L,日内和日间精密度考察中测定值的相对标准偏差(RSD)均小于0.5%。建立的方法适用于α-苯乙胺的质量控制。     

高效液相色谱法测定精浆中过氧化脂质水平及其在男性不育症研究中的应用

采用高效液相色谱法测定精浆中过氧化脂质(lipid peroxidation,LPO)含量,研究了有正常生育能力的男子和不育症患者精浆中LPO含量水平差异及其对男子不育症的影响。精浆样品经酸化后,分解生成的丙二醛(malondialdehyde,MDA)与硫代巴比妥酸(thiobarbituric acid,TBA)缩合反应形成紫红色产物,以Lichrospher C18化学键合硅胶为固定相,0.025 mol/L KH2PO4 (pH 6.2)-甲醇(体积比为58∶42)为流动相进行色谱等度分离     

稳定同位素稀释离子色谱-三重四极杆质谱法测定血浆和尿液中的氟乙酸

建立了离子色谱-三重四极杆质谱测定血浆和尿液样品中氟乙酸（MFA）的方法。血浆样品经高氯酸超声提取,尿液样品经高氯酸酸化,血浆和尿液提取液在pH 0.5~1.0条件下用叔丁基甲醚（MTBE）萃取,萃取液经氮吹浓缩后溶于0.1%（v/v）氨水溶液。以Ionpac AS 19型阴离子色谱柱为分析柱,在线自动产生的氢氧化钾作为淋洗液进行梯度分离,柱流出液经阴离子抑制器抑制后进入质谱系统。采用电喷雾电离源,在负离子、多离子监测（MRM）模式下检测,¹³C₂-氟乙酸稳定同位素内标法定量。血浆和尿液样品中氟乙酸的平均加标回收率为96.2%~120%,相对标准偏差为1.1%~13.1%（n=6）,方法的检出限（S/N=3）分别为0.03 μg/L和0.1 μg/L。该法简单、灵敏、准确,可用于生物样品中氟乙酸的检测。     

Determination of tanshinone I in rat plasma by high-performance liquid chromatography and its application to pharmacokinetic studies

This paper describes a rapid and sensitive high-performance liquid chromatographic (HPLC) method for the determination of the concentration of tanshinone I in rat plasma, and applies the method to pharmacokinetic study. The plasma is deproteinized with acetonitrile containing an internal standard (estradiolbenzoate). The HPLC assay is carried out using a Cosmosil C18 column. The mobile phase is acetonitrile, 0.05 mol/L(-1) ammonium acetate buffer with 1% acetic acid (66:34, v/v). The flow rate is 1.0 mL/min. The detection wavelength is set at 263 nm. The assay accuracy is better than 92%, and the precision of tanshinone I at low to high concentrations is better than 9% and 11% for intra-day and inter-day assays, respectively. The recovery of the method exceeds 88.3% for tanshinone I. The assay shows good linearity (r = 0.9998) over a relatively wide concentration range from 0.05 to 10.0 microg/mL. The method is used to determine the concentration-time profiles of tanshinone I in plasma following an intravenous injection of tanshinone I solution, and the pharmacokinetic parameters of tanshinone I are calculated for the first time by the Drug and Statistics 1.0 program. This assay is successfully applied to the determination of tanshinone I in rat plasma, and the developed method is applied to pharmacokinetic studies for the first time.     

全氟辛酸的3,4-二氯苯胺衍生化及高效液相色谱分析

介绍了一种可用于环境污染物全氟辛酸（PFOA）检测的高效液相色谱/紫外检测（HPLC/UV）分析方法。首先选用3,4-二氯苯胺为衍生化试剂,利用碳二亚胺法合成PFOA的酰胺化衍生产物（其在255 nm处紫外吸收最大）。然后确定四氢呋喃或水相介质中mg/L水平PFOA的衍生化条件及薄层硅胶色谱净化步骤。建立柱前衍生-HPLC/UV方法,以合成的全氟辛酸-3,4-二氯苯酰胺为对照品,外标法定量,PFOA上机测定的定量限为0.5 mg/L。通过加标回收试验评价方法的准确性,其中有机相及水相衍生法的回收率分别为91.8%~108.7%及40.1%~53.7%。与已报道的柱前衍生-HPLC/UV方法比较,本方法具有反应条件温和、衍生产物稳定、原料廉价易得、操作简单、成本低等优点。将本方法应用于光催化降解研究中PFOA的降解动力学实验,结果与液相色谱-质谱联用方法（LC/MS）的结果一致,说明本方法具有较好的应用前景。     

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

A simple high-performance liquid chromatography (HPLC) method is described for the determination of matrine in rat plasma. The plasma was deproteinized with acetonitrile that contained an internal standard (phenacetin) and was separated from the aqueous layer by adding sodium chloride. Matrine was extracted into the acetonitrile layer with high yield, and determined by reversed-phase HPLC (column: YMC-pack ODS-A, 5 μm, 150×4.6 mm, I.D.; eluent: acetonitrile-0.02 mol ammonium acetate buffer-triethylamine (35:65:0.035, v/v/v) and ultraviolet detection (220 nm). The limit of quantitation for matrine was 200 ng ml⁻¹ in plasma, and the recovery was greater than 89%. The assay was linear from 0.5 to 50.0 μg ml⁻¹. Variation over the range of the standard curve was less than 6%. The method was used to determine the concentration-time profiles of matrine in the plasma following oral administration of matrine aqueous solution or bolus injection from which the fractions of matrine reaching the systemic circulation were estimated by a deconvolution method for the first time.     

高效液相色谱法测定人血浆中奥氮平的浓度

 用高效液相色谱法测定了人血浆中奥氮平的浓度。色谱条件 :采用岛津LC 6A型高效液相色谱仪 ;色谱柱为ZorbaxODS (15 0mm× 4 6mmi d ,粒径 5 μm) ;流动相为V(5 0mmol/L磷酸钠缓冲液 ,pH 7 2 )∶V(甲醇 )∶V(乙腈 ) =12∶10∶3的溶液 ;检测波长为 2 70nm ;流速为 1 0mL/min ;柱温 40℃ ;灵敏度 0 0 0 5AUFS ;纸速 2mm/min。实验结果显示 ,在上述条件下 ,该方法的线性范围为 15 μg/L～ 12 0 0 μg/L(r =0 9988) ,最低检测限为 3μg/L ,血浆中奥氮平的平均回收率为 (97 0 2± 3 11) % ,测定结果的日内平均相对偏差为 3 86 % (n =15 ) 。     

HPLC analysis and pharmacokinetic study of quercitrin and isoquercitrin in rat plasma after administration of Hypericum japonicum thunb. extract

A simple HPLC method was developed for determination of quercitrin and isoquercitrin in rat plasma. Reversed-phase HPLC was employed for the quantitative analysis using kaempferol-3-O-beta-D-glucopyranoside-7-O-alpha-L-rhamnoside as an internal standard. Following extraction from the plasma samples with ethyl acetate-isopropanol (95:5, v/v), these two compounds were successfully separated on a Luna C(18) column (250 x 4.6 mm, 5 microm) with isocratic elution of acetonitrile-0.5% aqueous acetic acid (17:83, v/v) as the mobile phase. The flow-rate was set at 1 mL/min and the eluent was detected at 350 nm for both quercitrin and isoquercitrin. The method was linear over the studied ranges of 50-6000 and 50-5000 ng/mL for quercitrin and isoquercitrin, respectively. The intra- and inter-day precisions of the analysis were better than 13.1 and 13.2%, respectively. The lower limits of quantitation for quercitrin and isoquercitrin in plasma were both of 50 ng/mL. The mean extraction recoveries were 73 and 61% for quercitrin and isoquercitrin, respectively. The validated method was successfully applied to pharmacokinetic studies of the two analytes in rat plasma after the oral administration of Hypericum japonicum thunb. ethanol extract.     

High-performance liquid chromatographic method with ultraviolet detection for the determination of dapsone and its hydroxylated metabolite in human plasma

A validated high-performance liquid chromatographic method with ultraviolet detection for the quantitative determination of dapsone (4,4'-diaminodifenyl sulfone, DDS) and a metabolite, hydroxylaminodapsone (4-amino-4-hydroxylaminodiphenyl sulfone, DDS-NOH), in human plasma is described. Human plasma was deproteinized with acetone and the clear supernatant solution after centrifugation was evaporated to dryness under a gentle stream of nitrogen at 70 degrees C. The residue was dissolved in a mixture of HPLC eluent and acetone (18:5 v/v) and an aliquot of this solution (50 microL) was injected onto the HPLC column. Dapsone, hydroxylaminodapsone and diazoxide as internal standard, were separated within 10 min by isocratic elution with water:acetonitrile:glacial acetic acid:triethylamine (80:20:1.0:0.5 by volume) as eluent. Detection was by ultraviolet at the wavelength of 295 nm. The within-day repeatability coefficients of variation were 3-5% for dapsone (0.301-20.0 mg/L, n = 5) and 3-5% for hydroxylaminodapsone (0.0948-6.32 mg/L, n = 5), whereas the between-day repeatability coefficients of variation were 3-8% (0.301-20.0 mg/L, n = 5) for dapsone and 4-10% for hydroxylaminodapsone (0.0948-6.32 mg/L, n = 5). The mean recoveries -were 92-107% (0.301-20.0 mg/L, n = 2), 80-82% (0.0948-6.32 mg/L, n = 2) and 88% (0.0200 mg/mL, n = 5), for dapsone, hydroxylaminodapsone and diazoxide, respectively. The average correlation coefficient of the calibration curve was 0.99988 (n = 5) for dapsone at a concentration range of 0.301-20.0 mg/L, whereas the average correlation coefficient of the hydroxylaminodapsone calibration curve was 0.99981 (n = 5) at a concentration range of 0.0948-6.32 mg/L. The limits of detection were 0.00200 and 0.0470 mg/L for dapsone and hydroxylaminodapsone, respectively. The method is suitable for drug level monitoring and for pharmacokinetic studies.     

Determination of tryptophan and kynurenine in human plasma by liquid chromatography-electrochemical detection with multi-wall carbon nanotube-modified glassy carbon electrode

A novel method was developed for the simultaneous determination of kynurenine and tryptophan by high‐performance liquid chromatography with electrochemical detection at multi‐wall carbon nanotube (MWCNT)‐modified glassy carbon electrode. The separation and detection conditions were optimized. The typical HPLC experiments were conducted by using a reversed‐phase ODS column with a mobile phase consisting of stock acetate buffer (pH 5)–methanol (4:1, v/v) using an isocratic elution at the flow rate of 1.0 mL/min. The obtained LODs for kynurenine and tryptophane were 0.5 and 0.4 µmol/L, respectively. The analytical method for human plasma samples was validated and confirmed by LC‐UV and LC‐MS. The recoveries were in the range of 84.8–110%, and the precision was lower than 5.9%. Copyright © 2010 John Wiley & Sons, Ltd.     

A new HPLC method with fluorescence detection for the determination of memantine in human plasma

A sensitive, selective, simple and fast HPLC method based on the formation of derivative with fluorescamine was developed for the determination of memantine (ME) in human plasma. Separation was achieved on a CN column (200 mm×4.6 mm) using acetonitrile-10 mM orthophosphoric acid containing 1 mL/L triethylamine (45:55, v/v) at a flow rate of 1 mL/min. Emission and excitation wavelengths were 480 and 380 nm, respectively. Amantadine was used as an internal standard. Calibration graphs were rectilinear over the range of 1.0-100.0 ng/mL. Limit of detection and limit of quantification were found to be 0.3 and 1.0 ng/mL, respectively. Intra-day and inter-day relative standard deviation values were found to be <2.03%. Average recovery was also found to be around 94%. Proposed method was applied for the pharmacokinetic study in a healthy volunteer after a single oral administration of 20 mg of ME.     

Development and validation of bioanalytical method for quantification of cycloserine in human plasma by liquid chromatography–tandem mass spectrometry: Application to pharmacokinetic study

A selective, sensitive and high‐throughput liquid chromatography–tandem mass spectrometry bioanalytical method has been developed for the estimation of cycloserine in human plasma, employing cytosine as the internal standard. The extraction of the analyte was facilitated by solid‐phase extraction using 100 μL of human plasma. The separation was carried out on a BDS Hypersil C₁₈ (150 × 4.6 mm, 5 μm) column using a mixture of 0.2% formic acid in HPLC‐grade water, methanol and acetonitrile (70:15:15, v/v/v) as mobile phase at a flow rate of 1.0 mL/min. The method was linear over the range of 0.20–20 μg/mL with r² > 0.99. Complete validation of the method was performed as per US Food and Drug Administration guidelines and the results met acceptance criteria. Applying the present method, the clinical pharmacokinetics of cycloserine following oral administration of 250 mg cycloserine was studied under fasting conditions. Assay reproducibility was also verified by incurred sample reanalysis.     

High Performance Liquid Chromatographic Determination of Amiodarone in Plasma and Tissues

Abstract

A simple and rapid high-performance liquid chromatographic (HPLC) method for the determination of amiodarone (AD) in plasma and tissues was developed. The method involved deproteinization of plasma or homogenized tissue with acetonitrile containing an internal standard (N-Cetylpyridinium chloride) followed by reversed phase chromatography using μ bondapack C₁₈ column (10μm) with a mobile phase consisting of acetonitrile - methanol - sodium dihydrogen phosphate buffer (70:10:20%, v/v), the pH adjusted to 4.0 and pumped at flow rate of 1.0 ml/min. The column effluent was monitored at 242 nm. A linear relationship was obtained between peak height ratios (drug to internal standard) versus drug levels over the concentration range of 50–750 ng/ml. The detection limit of AD in plasma and tissues by this method was 20 ng/ml.     

Determination of captopril in human plasma with precolumn derivatization using solid phase extraction and HPLC

A rapid, accurate and sensitive method for the determination of captopril in human plasma was developed by solid phase extraction and high performance liquid chromatography (HPLC), using precolumn derivatization of captopril with chromophore label o-phethaldialdehyde (OPA). The extraction of captopril from human plasma was carried out by an amino propyl cartridge. A 0.01 M solution of HCl in methanol showed the best recovery and was chosen for elution of captopril in cartridge. This methanolic solution was applied to react with aqueous solution of OPA and glycine as a coderivatization reagent. The process of derivatization was completed within 2 min at room temperature. The derivatized captopril was injected into a reverse phase HPLC system. Mobile phase was consisted of water:acetonitrile:trifluoroacetic acid (85:15:0.1 v/v/v) with a flow rate of 1 ml min^?1 and detector was used at 345 nm. Linear dynamic range and limit of detection were found as 0.1–6 ppm and 0.1 ppm, respectively.     

HPLC analysis and pharmacokinetics of icariin in rats

As a prerequisite to the determination of pharmacokinetic parameters of icariin in rats, an HPLC method using UV detection was developed and validated. Icariin and the internal standard, quercetin, were extracted from plasma samples using ethyl acetate after acidification with 0.05 mol/L NaH2PO4 solution (pH 5.0). Chromatographic separation was achieved on an Agilent XDB Cls column (250 x 4.6 mm id, 5 microm) equipped with a Shim-pack GVP-ODS C18 guard column (10 x 4.6 mm id, 5 microm) using a mobile phase of ACN/water/acetic acid (31:69:0.4 v/v/v) at a flow rate of 1.0 mL/ min. Detection was at 277 nm. The calibration curve was linear from 0.05 to 100.0 microg/mL with 0.05 microg/mL as the lower LOQ (LLOQ) in plasma. The intra- and interday precisions in terms of RSD were lower than 5.7 and 7.8% in rat plasma, respectively. The accuracy in terms of relative error (RE) ranged from -1.6 to 3.2%. The extraction recoveries of icariin and quercetin were 87.6 and 80.1%, respectively. The main pharmacokinetic parameters for rats were determined after a single intravenous administration of 10 mg/kg icariin: t1/2, 0.562 +/- 0.200 h; AUC0-infinity, 8.73 +/- 2.23 microg x h/mL; CLToT, 20.10 +/- 5.80 L/kg x h; Vz, 1.037 +/- 0.631 L/kg; MRT0-infinity, 0.134 +/- 0.040 h; and Vss, 0.170 +/- 0.097 L/kg.     

Sensitive HPLC Assay for Ketoprofen in Human Plasma and its Application to Pharmacokinetic Study

Abstract

A selective and sensitive HPLC method was developed for the analysis of ketoprofen in human plasma. The assay involves an extraction of the drug and the internal standard (piroxicam) into diethyl ether from acidified plasma and then back-extracted into a small volume of alkaline aqueous solution before injection onto the HPLC column. A microbore column (2 mm I.D. × 10 cm) packed with a C18 reversed-phase material (5 pm ODS Hypersil) was used. The chromatographic separation was accomplished with a mobile phase comprising a mixture of acetonitrile-methanol-water (15 :20 : 65, v/v) containing 10 mM Na2HP04 buffer, pH 4. The mobile phase was pumped at a flow rate of 0.5 dmin. The eluant was monitored at 258 nm. With this procedure coefficients of variation were less than 10%. The detectionlimit was 0.05 μg/ml (i.e., 50 ng/ml) of plasma. The highly sensitive nature of this method was applied successfully to the dewmination of ketoprofen in human plasma for phmacokinetic studies.