高效液相色谱-串联质谱法测定比格犬血浆中的莫诺苷浓度及其药代动力学

运用高效液相色谱-串联质谱联用技术,建立了简单、快速、灵敏的比格犬灌胃莫诺苷后血药浓度的检测方法。血浆样品采用蛋白质沉淀法处理,以芍药苷作为内标,色谱柱为Inertsil ODS-SP色谱柱(50 mm×2.1 mm,5μm),流动相为水(含1 mmol/L甲酸钠)-乙腈,梯度洗脱,流速0.4 mL/min。采用电喷雾离子源(ESI),正离子多反应监测(MRM)模式。绘制血药浓度-时间曲线,并采用DAS 2.0软件计算药代动力学参数。方法学实验结果表明内源性杂质不干扰莫诺苷和内标的测定,线性范围为2~5 000μg/L(r=0.996 6),定量限为2μg/L。方法精密度、准确度、回收率和基质效应均符合生物样品测定的要求,适合比格犬血浆中莫诺苷浓度的测定,可以应用该方法进行莫诺苷的药代动力学研究。比格犬灌胃莫诺苷3个剂量(5、15、45 mg/kg)后的血药浓度-时间曲线下面积(AUC(0-∞))分别为(1 631.20±238.50)、(3 984.05±750.38)、(10 397.64±3 156.34)μg/L·h,与给药剂量之间呈现良好的线性关系。     

加速溶剂萃取-超高效液相色谱-串联质谱快速测定棉花中残留的8种脱叶剂

采用加速溶剂萃取结合超高效液相色谱-串联质谱(UPLC-MS/MS)技术,建立了一种快速提取和测定棉花中8种脱叶剂(噻苯隆、脱叶磷、甲基苯噻隆、脱落酸、氟酮唑草酯、敌草隆、百草枯、嘧草硫醚)的分析方法。样品经提取、浓缩,乙腈-水溶液(1:9, v/v)溶解,采用Acquity UPLC^® HSS T3柱(50 mm×2.1 mm, 1.8 μ m)分离,以乙腈-0.05%(v/v)甲酸水溶液为流动相,梯度洗脱,电喷雾正离子模式多反应监测,外标法定量。该方法在0.01~0.3 mg/L范围内线性关系良好(r >0.99),在添加含量水平为0.1、0.5、1.0 mg/kg时,平均回收率范围为(84.18±8.04)%~(95.99±6.76)%,相对标准偏差(RSD)为7.04%~10.60%,方法检出限(LOD)为0.8~29 μ g/kg,方法定量限(LOQ)为2.5~96 μ g/kg。该方法操作简便、快捷、灵敏、准确,适合棉花中8种脱叶剂的确证和定量测定。     

凝胶渗透色谱净化-超高效液相色谱-串联质谱法测定皮革制品中7种尼泊金酯类防腐剂

利用超高效液相色谱-串联质谱(UPLC-MS/MS)结合凝胶渗透色谱(GPC)技术,建立了一种快速分离和测定皮革制品中7种尼泊金酯类防腐剂的分析方法。样品经超声提取、浓缩、GPC净化,甲醇-水溶液(1:1, v/v)溶解,采用Acquity UPLCBEH C18柱(50 mm×2.1 mm, 1.7 μm)分离,以甲醇和水为流动相,梯度洗脱,电喷雾负离子模式电离,采用多反应监测模式检测和外标法定量。该方法在0.1～1.0 mg/L范围内线性关系良好(r＞0.99);在添加量为0.5～3.0 mg/kg时,平均回收率为(79.44±5.67)%～(98.07±9.50)%,相对标准偏差(RSD)为4.24%～14.00%;方法的检出限(LOD)为4～12 μg/kg,定量限(LOQ)为13.2～39.6 μg/kg。该方法操作简便、快捷、灵敏、准确,适合皮革中多种尼泊金酯类防腐剂的确证和定量测定。     

超高效液相色谱-电喷雾三重四极杆质谱法测定中药中马兜铃酸A和B的含量

利用超高效液相色谱-电喷雾三重四极杆质谱仪建立了中药中马兜铃酸A和B的定性定量分析方法。选取柴胡、生甘草、桔梗、龙胆泻肝丸、消胖丸、减肥茶等14种代表性样品,用甲醇-水(70:30, v/v)溶液加热回流提取,经Oasis MAX固相萃取柱富集净化后,在Eclipse RP HD C18反相柱(150 mm×2.1 mm, 1.8 μm)上进行分离;流动相为5 mmol/L乙酸铵水溶液(pH 7.5)-乙腈(75:25, v/v)。采用电喷雾离子源正离子模式(ESI+)和多反应监测模式(MRM)进行质谱分析。马兜铃酸A和B的线性范围分别为0.5～200 μg/L和1～200 μg/L,相关系数(r2)均大于0.995;检出限(LODs)分别为5 μg/kg和7.5 μg/kg;定量限(LOQs)分别为12.5 μg/kg和25 μg/kg。在100 μg/kg和500 μg/kg添加水平下,马兜铃酸A和B的回收率(n=6)范围分别为60.3%～96.4%和61.3%～94.7%,相对标准偏差均不大于10.2%。该方法灵敏度高,重复性好,操作简便,适用于中药材、饮片及中成药中马兜铃酸A和B的痕量检测。     

基于超滤离心前处理的液相色谱-串联质谱法手性拆分人血浆中的亚叶酸和5-甲基四氢叶酸非对映异构体及其药代动力学应用

建立了液相色谱-串联质谱（HPLC-MS/MS）同时测定人血浆中的亚叶酸和5-甲基四氢叶酸两对非对映异构体的方法。血浆经蛋白质沉淀-超滤离心处理后,以甲氨蝶呤为内标,乙腈-10 mmol/L pH 8.0醋酸铵为流动相,通过手性HSA色谱柱（150 mm×4 mm,5 μm）进行梯度洗脱。亚叶酸非对映异构体在25~5000 μg/L范围内、5-甲基四氢叶酸非对映异构体在12.5~2500 μg/L范围内,线性关系均良好。本方法在灵敏度、精密度、准确度、基质效应、提取回收率、稳定性等方面均得到充分验证,并成功应用于125 mg/m²亚叶酸和62.5 mg/m²左旋亚叶酸的药代动力学研究。结果显示：在125 mg/m²亚叶酸剂量组,左亚叶酸和左旋-5-甲基四氢叶酸的血浆峰浓度（C_max）为（3137.917±408.837）和（1679.633±244.132）μg/L,从时间点0到最后可定量时间点的药物代谢动力学时间曲线下面积（AUC_0-t）为（7504.883±1185.101）和（14001.214±2868.949）μg/L;在62.5 mg/m²左亚叶酸剂量组,左亚叶酸和左旋-5-甲基四氢叶酸的C_max为（3187.917±387.298）和（1739.204±224.755）μg/L,AUC_0-t为（7426.664±854.825）和（14884.331±1843.353）μg/L。两剂量组主要药物代谢动力学参数均无显著差异,特征一致,吸收的速度和程度一致,能够为后期进行左亚叶酸钠生物等效性研究提供技术支持。     

高效液相色谱-荧光检测法同时测定体外循环下狗血浆中的阿曲库铵和劳丹碱

建立了测定体外循环下狗血浆中阿曲库铵及其代谢产物劳丹碱的高效液相色谱-荧光检测(HPLC-FLD)分析方法。使用Agilent Eclipse Plus C18色谱柱分离,以0.03 mol/L磷酸氢二钾(pH 5.0)-乙腈(72:28, v/v)为流动相,流速1.0 mL/min。以维拉帕米为内标,样品经二氯甲烷萃取、浓缩后以流动相溶解进样,荧光检测的激发波长和发射波长分别为240和320 nm。结果表明,阿曲库铵和劳丹碱分别在25~5000 μ g/L和25~6000 μ g/L范围内线性关系良好(r=0.9990和r=0.9984);方法回收率在92.1%~109.5%之间;检出限分别为3 μ g/L和1 μ g/L;日内和日间精密度(以RSD计)均小于10%;稳定性试验结果显示样品在不同存储条件下的稳定性良好。该方法选择性好,灵敏度高,结果准确,重现性好,可用于阿曲库铵和劳丹碱的血药浓度测定及其药代动力学研究。     

高效液相色谱-串联质谱法测定荔枝花粉和花蜜中腈菌唑和苯醚甲环唑残留

采用改良的QuEChERS-高效液相色谱-串联质谱（HPLC-MS/MS）技术,建立了荔枝花粉和花蜜中2种主要杀菌剂腈菌唑和苯醚甲环唑的测定方法。花粉和花蜜样品均由乙腈提取,花粉样品经0.9 g无水硫酸镁、0.15 g N-丙基乙二胺（PSA）和0.15 g十八烷基键合硅胶（C₁₈）吸附剂净化,花蜜样品由0.9 g无水硫酸镁和0.15 g PSA净化。采用Poroshell-120 EC-C₁₈色谱柱分离,以0.1%（v/v）甲酸水溶液-乙腈（25∶75,v/v）为流动相等度洗脱,在电喷雾离子（ESI）源、正离子扫描和选择离子监测模式下进行检测,基质匹配标准溶液法定量。结果显示：腈菌唑和苯醚甲环唑在1~100 μg/L范围内线性关系良好,相关系数（r²）均大于0.9990;腈菌唑和苯醚甲环唑的检出限（LOD）分别为0.25 μg/kg和0.50 μg/kg,定量限（LOQ）分别为0.83 μg/kg和1.7 μg/kg;腈菌唑和苯醚甲环唑在荔枝花粉和花蜜样品中的平均加标回收率分别为87.0%~95.2%和90.1%~96.4%,相对标准偏差（RSD）分别为1.2%~3.6%和0.7%~4.1%。该法快速、简便、灵敏,可用于荔枝花粉和花蜜样品中腈菌唑和苯醚甲环唑的痕量测定,可为蜜蜂等授粉昆虫的暴露性风险评估提供技术支持。     

胶束电动色谱-激光诱导荧光检测法测定肌松弛药巴氯芬

以4-氯-7-硝基苯并-2-氧杂-1,3-二唑(NBD-Cl)为柱前衍生试剂,建立了胶束电动色谱-激光诱导荧光检测法测定肌松弛药巴氯芬(BAL)的新方法。经过实验条件的优化,采用15 mmol/L硼砂、20 mmol/L十二烷基硫酸钠、10%(v/v)乙腈、pH 9.75的缓冲体系,在分离电压为17.5 kV、柱温为25 ℃的条件下,压力进样3.45 kPa(0.5 psi)×3 s,巴氯芬及其内标物的衍生产物在7 min内实现较好的基线分离,线性范围为0.025～25 mg/L,相关系数为0.9999,检出限(S/N=3)和定量限(S/N=10)分别为0.90 μg/L和6.25 μg/L。该方法被应用于巴氯芬制剂及加入巴氯芬对照品的尿液样品分析,回收率范围分别为101.6%～107.9%和107.0%～109.6%。该方法有望应用于巴氯芬药物制剂的质量监控以及为巴氯芬药物代谢的研究提供辅助手段。     

液相色谱-串联质谱法检测水产品中残留的硝基呋喃类药物的代谢物

建立了液相色谱-串联质谱(LC-MS/MS)法用于同时测定水产品中硝基呋喃类药物的代谢物3-氨基-2-唑烷基酮(AOZ)、5-甲基吗啉-3-氨基-2-唑烷基酮(AMOZ)、氨基脲(SEM)、1-氨基-2-内酰脲(AHD)和3,5-二硝基水杨酸肼(DNSH)。样品经盐酸水解、2-硝基苯甲醛衍生、乙酸乙酯提取净化。氮吹至干后,用1 mL乙腈-0.1%甲酸水(20:80, v/v)定容。经Aquasil C18色谱柱分离,用液相色谱-三重四极杆串联质谱以多反应监测模式(MRM)进行检测分析,内标法定量。结果表明,该方法的线性范围为0.5～10 μg/kg, 5种代谢物的线性相关系数均不小于0.9976,定量限为0.5 μg/kg。在0.5、1.0、2.0和4.0 μg/kg的添加水平下,加标回收率为81.3%～100.5%, RSD为3.4%～10.0%。本法可作为水产品中5种硝基呋喃类药物的代谢物残留量同时分析的有效手段。     

超高效液相色谱-四极杆飞行时间质谱快速检测动物饲料中10种违禁精神药物

建立了测定动物饲料中三唑仑、艾司唑仑、硝西泮、地西泮、异丙嗪、氯氮平、唑吡坦、甲硫哒嗪、氯丙嗪和咪达唑仑10种违禁精神药物的超高效液相色谱-四极杆飞行时间质谱(UPLC-Q-TOF-MS)方法。样品经混合溶剂甲醇-0.1 mol/L HCl(9:1, v/v)振荡提取,再用MCX固相萃取柱净化处理后,采用UPLC-Q-TOF-MS分析检测。10种化合物在5～100 μg/L范围内均呈良好的线性关系,线性相关系数均大于0.99。本方法的硝西泮、唑吡坦和甲硫哒嗪的定量限(LOQ,以信噪比为10计)为8 μg/kg,三唑仑、艾司唑仑、地西泮、异丙嗪、氯丙嗪和咪达唑仑为10 μg/kg,氯氮平为20 μg/kg。3个添加水平(LOQ、2LOQ、4LOQ)的回收率试验结果表明,10种化合物的回收率在60.6%～108.5%范围内,相对标准偏差均小于10%。本方法可用于动物饲料中违禁精神药物的准确测定。     

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.     

高效液相色谱法测定大鼠血浆中的原儿茶酸

建立了大鼠血浆中原儿茶酸含量测定的高效液相色谱方法。采用的色谱柱为DiamondsilTM C18 柱(150 mm×4.6 mm,5 μm);流动相为乙腈-水(体积比为9∶91,用H3PO4 调pH至2.5);流速1.2 mL/min;检测波长260 nm;内标为对羟基苯甲酸。原儿茶酸的线性范围为0.050~3.20 mg/L,线性相关系数为0.9978，最低定量限为0.050 mg/L,日内和日间测定的精密度（以相对标准偏差表示）均低于7.0%,准确度（以相对误差表示）为-1.4%～2.6%；在0.050,0.40,3.20 mg/L低、中、高3个添加浓度水平下，血浆样品的提取回收率分别为83.4%,87.3%,91.1%。该方法简便,灵敏,准确,适用于大鼠体内原儿茶酸的药物动力学研究。     

Development of an HPLC method for the determination of salidroside in beagle dog plasma after administration of salidroside injection: application to a pharmacokinetics study

A simple RP-HPLC method was established for the determination of salidroside in dog plasma. Salidroside is one of the most active ingredients of Rhodiola L. The method had within-run precision values in the range of +/- 2.3 to +/- 9.1% (n = 5) and between-run precision in the range of +/- 3.2 to +/- 9.8%. A simple protein precipitation for salidroside extraction was processed using ACN at precipitant-to-plasma volume ratio (P-P ratio) of 3:2. The extraction recoveries of salidroside at seven concentrations were higher than 63.2%. There was a linear relationship between chromatographic area and concentration over the range of 0.83-520 microg/mL for salidroside in plasma (R = 0.9926). The LOQ (S/N = 10) of the method was 0.83 microg/mL. The method was applied in a study of the pharmacokinetics of salidroside injection in six beagle dogs. The major pharmacokinetic parameters of C(max), AUC(0-24), AUC(0-infinity), and t(1/2) of salidroside in beagle dogs after i.v. administration of a single 75 mg/kg (5 mL/kg) dose were 96.16 +/- 8.59 microg/mL, 180.3 +/- 30.6 microg h/mL, 189.3 +/- 32.1 microg h/mL, and 2.006 +/- 0.615 h, respectively.     

HPLC determination of andrographolide in rat whole blood: study on the pharmacokinetics of andrographolide incorporated in liposomes and tablets

A sensitive and simple high-performance liquid chromatographic method with UV detection was developed and validated for the determination of andrographolide in rat whole blood. Carbamazepine was employed as internal standard and the blood sample was extracted with chloroform. Chromatographic separations were achieved on a Chromasil ODS column (250 x 4.6 mm, 5 microm). The mobile phase was consisted of methanol-water (52:48, v/v) and delivered at 0.8 mL/min. The detection wavelength was set at 225 nm. The calibration curve had a good linearity in the range 0.053-530 microg/mL in rat whole blood with its correlation coefficient being 0.996. The extraction recovery of andrographolide was ranged from 65.7 to 72.6%. The intra-day and inter-days repeatabilities were below 4.2% in terms of the percentage of relative standard deviation (RSD). The method was used to provide data on the pharmacokinetics of the drug in rats. The data obtained was processed using the 3P87 pharmacokinetic program. The results showed that the disposition of andrographolide after intravenous administration of liposomal andrographolide conformed to a two-compartment open model with alpha = 4.75 x 10(-2) +/- 2.41 x 10(-3) min(-1), beta = 3.16 x 10(-3) +/- 1.58 x 10(-4) min(-1), V(c) = 174.67 +/- 13.97 mL, k(21) = 1.60 x 10(-2) +/- 8.12 x 10(-4) min(-1), k(10) = 9.38 x 10(-3) +/- 5.62 x 10(-4) min(-1), k(12) = 2.53 x 10(-2) +/- 1.27 x 10(-3) min(-1) and AUC(0-infinity) = 1525.47 +/- 92.35 microg min/mL. For the intragastric administration of andrographolide tablets, the disposition of andrographolide followed a one-compartment open model with k(e) = 6.78 x 10(-3) +/- 3.53 x 10(-4) min(-1), k(a) = 3.69 x 10(-2) +/- 4.68 x 10(-3) min(-1), T(max) = 59.69 +/- 3.61 min, C(max) = 1.62 +/- 0.11 microg/mL, V(c) = 1056.90 +/- 83.42 mL, AUC(0-infinity) = 348.75 +/- 24.41 microg min/mL.     

Pharmacokinetic study of puerarin in rat serum by liquid chromatography tandem mass spectrometry

A highly sensitive and specific atmospheric pressure chemical ionization liquid chromatography-tandem mass spectrometry method was developed for serum pharmacokinetic studies of puerarin in rats. Chromatography was carried out on a reversed-phase Phenomenex Synergi 4 microm Fusion-RP80 column (150 x 2.0 mm i.d.) using a mobile phase consisting of acetonitrile-water (10:90, v/v) in 10 mm NH(4)OAc with a flow rate of 0.2 mL/min. Puerarin was analyzed in the multiple reaction monitoring mode with a precursor/product ion transition of m/z 415/267. The method was demonstrated to be specific and sensitive, and a linear response was observed over a range of 2-5000 ng/mL in rat serum. The validated method was successfully applied to the characterization of the pharmacokinetics of puerarin in rat serum after oral administration to spontaneously hypertensive rats. The blood concentration-time profile of puerarin showed a rapid initial increase, reaching a maximum and then declining within 1 h. Puerarin could not be detected after 24 h. The main pharmacokinetic parameters for puerarin after oral administration were as follows: C(max) (3.54 +/- 2.03 mg/L), T(max) (0.68 +/- 0.37 h), AUC(0-t) (7.29 +/- 3.79 mg h/L), AUC(0-infinity) (9.17 +/- 4.87 mg h/L), T(1/2) (1.7 +/- 0.6 h), CL/F (7.24 +/- 4.27 L/h/kg) and V/F (17.88 +/- 13.55 L/h/kg).     

Investigation of the pharmacokinetics of celecoxib by liquid chromatography-mass spectrometry

A new method for the quantification of celecoxib in human plasma based on reversed-phase high-performance liquid chromatography (HPLC) coupled to atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) after liquid-liquid extraction is presented. The method is rapid, sensitive and highly selective. The retention time of celecoxib was 2.3 min. The limit of quantification was 5 microg/L. Rofecoxib was used as internal standard. After validation, the method was used to study the pharmacokinetic profile of celecoxib following administration of a single oral dose (200 mg) in 12 healthy volunteers. Since celecoxib should be metabolized primarily by cytochrome 2C9 (CYP2C9), a poor metabolizer (PM) for this cytochrome P450 enzyme was included in the study. Pharmacokinetic characteristics (mean +/- SD) of extensive metabolizers (EM) were t(max) 2.9+/-1.2h, c(max) 842+/-280 microg/L, AUC(infinity) 6246+/-2147 microg h/L and t(1/2) 7.8+/-2.7h. The area under the curve (AUC(infinity)) for the PM was 12561 microg h/L. However, we found no noticeable increase in half life in the PM (11.5 h) after a single dose of celecoxib.     

A simple HPLC method for the quantification of mizoribine in human serum: pharmacokinetic applications

A simple high-performance liquid chromatographic (HPLC) method was developed and validated for the quantification of mizoribine in human serum. After the addition of 70% perchloric acid and 3-methylxanthine (50 microg/mL, internal standard) to human serum, the samples were mixed and centrifuged at 12,000 rpm (1432 g) for 10 min. The supernatant was injected onto a C(18) column eluted with a mobile phase of 20 mm Na2HPO4 and methanol (93:7, v/v, pH 3) containing 0.04% octanesulfonic acid and detected utilizing an ultraviolet detector at 275 nm. The linear calibration curve was obtained in the concentration range of 0.1-4.0 microg/mL and the lower limit of quantification was 0.1 microg/mL. This method was validated with selectivity, linearity, precision and accuracy. In addition, the method was successfully applied to estimate the pharmacokinetic parameters of mizoribine in Korean subjects following an oral administration of 100 mg mizoribine (two Bredinine 50 mg tablets). The maximum serum concentration (C(max)) of 2.30 +/- 0.83 microg/mL was reached 2.27 +/- 0.66 h after an oral dose. The mean AUC(0-12 h) and the elimination half-life (t(1/2)) were 13.2 +/- 4.79 microg h/mL and 3.10 +/- 0.74 h, respectively.     

Enantioselective analysis of ibuprofen in human plasma by anionic cyclodextrin-modified electrokinetic chromatography

This paper reports the development of a rapid method for the enantioselective analysis of the nonsteroidal anti-inflammatory drug ibuprofen in human plasma by capillary electrophoresis employing the anionic cyclodextrin-modified electrokinetic chromatography mode. Sample cleanup was carried out by acidification with HCl followed by liquid-liquid extraction with hexane:isopropanol (99:1 v/v). The complete enantioselective analysis was performed within 10 min, using 100 mmol L(-1) phosphoric acid/triethanolamine buffer, pH 2.6, containing 2.0% w/v sulfated beta-cyclodextrin as chiral selector; fenoprofen, another nonsteroidal anti-inflammatory drug, was used as internal standard. The calibration curves were linear over the concentration range of 0.25-125.0 microg mL(-1) for each enantiomer of ibuprofen. The mean recoveries for ibuprofen enantiomers were up to 85%. The enantiomers studied could be quantified at three different concentrations (0.5, 5.0 and 50.0 microg mL(-1)) with a coefficient of variation and relative error not higher than 15%. The quantitation limit was 0.2 microg mL(-1) for (+)-(S)- and (-)-(R)-ibuprofen using 1 mL of human plasma. The plasma endogenous compounds and other drugs did not interfere with the present assay. The analysis of real plasma samples obtained from a healthy volunteer after administration of 600 mg of racemic ibuprofen showed a maximum plasma level of 29.6 and 39.9 microg mL(-1) of (-)-(R)- and (+)-(S)-ibuprofen, respectively, and the area under plasma concentration-time curve AUC(0-infinity) (+)-(S)/AUC(0-infinity) (-)-(R) ratio was 1.87.     

Concurrent measurement of unbound genistein in the blood, brain and bile of anesthetized rats using microdialysis and its pharmacokinetic application

Genistein, the major isoflavone in soybeans, has been shown to have a wide range of effects. We used an HPLC-UV combined with microdialysis method to detect unbound genistein in rat blood, brain and bile. Genistein dialysates were eluted with a mobile phase containing acetonitrile-water (40:60, v/v, pH 3.5 adjusted by 0.1% acetic acid). Samples were separated using a phenyl (5 microm) column maintained at ambient temperature. The UV detector wavelength was set at 259 nm. The flow rate was 1.0 m/min. The limit of quantitation for genistein was 50 ng/ml. The in vitro recoveries of genistein were 31 +/- 1, 13 +/- 1 and 59 +/- 4% in microdialysis probes of blood, brain and bile, respectively (n = 4). Inter- and intra-assay accuracy and precision of the analysis were less than 10% in the concentration ranges of 0.05-5.0 microg/ml. A small ratio of genistein penetrates the blood-brain barrier (BBB) and goes through hepatobiliary excretion after genistein administration (10 or 30 mg/kg, i.v.). The brain-to-blood (AUC(brain)/AUC(blood)) and bile-to-blood (AUC(bile)/AUC(blood)) distribution ratios were 0.04 +/- 0.01 and 1.85 +/- 0.42, respectively for the dosage of genistein 30 mg/kg. After co-administration of cyclosporine, a P-glycoprotein (P-gp) inhibitor, the distribution ratios of genistein in brain and bile were not significantly altered. These results suggest that the BBB penetration and hepatobiliary excretion of genistein may not regulated by P-gp.     

Determination and pharmacokinetic study of syringin and chlorogenic acid in rat plasma after administration of Aidi lyophilizer

A high-performance liquid chromatographic (HPLC) method was developed for the first time to simultaneously quantify syringin and chlorogenic acid in rat plasma using wavelength-transfer technology. The analysis was performed on a Diamonsil C(18) column (200 x 4.6 mm i.d., 5 microm particle size) with isocratic mobile phase consisting of acetonitrile-0.05% phosphoric acid (12:88, v/v). The linear ranges were 0.20-10 and 0.25-30 microg/mL, respectively. The lower limits of quantification were 0.20 and 0.25 microg/mL, respectively. The method was shown to be reproducible and reliable with intraday precision below 8.5 and 6.1%, interday precision below 7.1 and 5.5%, accuracy within +/-7.1 and +/-8.6%, and mean extraction recovery excess of 92.1 and 80.9%, respectively, which were all calculated from the blank plasma sample spiked with syringin and chlorogenic acid at three concentrations of 0.20, 1.0 and 6.0 microg/mL for syringin and 0.25, 2.0 and 20 microg/mL for chlorogenic acid. This method was validated for specificity, accuracy and precision and was successfully applied to the pharmacokinetic study of syringin and chlorogenic acid in rat plasma after intravenous administration of Aidi lyophilizer.