尿中普萘洛尔对映体葡醛酸苷的HPLC测定

建立了人尿中普萘洛尔对映体葡醛酸苷无需水解、直接测定的HPLC法.采用生物合成获得普萘洛尔葡醛酸苷,并经C18固-液萃取纯化、浓集,作为对照品储备液.采用荧光检测器,激发波长和发射波长分别为310和339nm.线性范围0.0232～5.8μmol/L,r=0.9999.平均回收率为99.8%±5.01%,日内和日间精密度分别小于1.08%和2.86%.     

维拉帕米对映体在人体的药代动力学

目的： 考察维拉帕米(VPM)和去甲维拉帕米(NVPM)对映体的药代动力学特性。 方法： 8名汉族男性健康志愿者分别po外消旋VPM 80 mg和静滴5 mg,以三甲基-β-环糊精为手性选择剂,毛细管电泳法同时测定VPM和NVPM对映体的血浆浓度,用二房室开放模型拟合药-时曲线。结果： po VPM的R/S(AUC),R/S(CL)和R/S(C_max)比率分别为3.66±1.86,0.3±0.053和4.82±0.58;NVPM的R/S(C_max)和R/S(AUC)比率为2.58和2.36。iv VPM的R/S(AUC),R/S(CL)和R/S(C_max)比率分别为1.04±0.29,1.01±0.3和1.36±0.12。R-(+)-VPM和S-(-)-VPM的绝对生物利用度为30.3±19和9.8±5.9。结论： VPM有较大的对映体特异性首过代谢,选择优对映体S-(-)-VPM为监测对象有利于临床合理使用外消旋VPM。     

大鼠肝微粒体中芬氟拉明对映体氧化代谢的立体选择性研究

目的建立大鼠肝微粒体孵育液中l-和d-芬氟拉明的对映体选择性测定的方法,并用于研究芬氟拉明Ⅰ相代谢的立体选择性。方法将dl-芬氟拉明与大鼠肝微粒体孵育后,采用柱前衍生化毛细管气相色谱-氢火焰离子化检测法进行对映体的分离,测定时间反应曲线和酶动力学参数。结果单个对映体的线性范围是1～50μg/mL;l-和d-芬氟拉明的方法平均回收率分别为92.4%和95.5%,检测限和定量限分别为0.1μg/mL和1.0μg/mL,方法精密度为RSD<10%(n=6)。l-和d-芬氟拉明的K_m,V_max,Cl_int值分别为(0.15±0.01)和(0.27±0.02)μmol.mL^-1,(4.99±0.52)和(9.53±0.87)nmol.g^-1.min^-1,(33.3±3.0)和(35.3±3.1)mL.min^-1.g(蛋白)^-1。结论方法准确可靠,已用于l-和d-芬氟拉明在大鼠肝微粒体孵育液中的代谢及其动力学研究;结果表明,芬氟拉明在大鼠的Ⅰ相代谢具有对映体选择性。     

UHPLC-MS/MS法测定盐酸普萘洛尔缓释片中基因毒性杂质N-亚硝基普萘洛尔

目的 建立盐酸普萘洛尔缓释片中基因毒性杂质N-亚硝基普萘洛尔的UHPLC-MS/MS检测方法。方法 Waters ACQUITY UPLC® CSHTM C₁₈色谱柱(150 mm×3.0 mm, 1.7 μm),10 mmol•L^-1甲酸铵的水溶液（含0.1%甲酸）作为流动相A,乙腈溶液（含0.1%甲酸）作为流动相B,梯度洗脱,流速为0.5 mL•min^-1,柱温为50 ℃,进样器温度为5 ℃,进样体积为10 μL,采用多反应监测（MRM)模式,对盐酸普萘洛尔缓释片中的N-亚硝基普萘洛尔进行定量检测。结果 N-亚硝基普萘洛尔在1～20 ng•mL^-1范围内具有良好的线性关系。低、中、高3个浓度的加样回收率（n=3）在98.4%～103.2%之间,RSD≤2.7%。检测限和定量限分别为0.09 ng•mL^-1和0.3 ng·mL^-1。检出盐酸普萘洛尔缓释片中基因毒性杂质N-亚硝基普萘洛尔含量为1.8 μg•g^-1。结论 该方法灵敏度高、专属性强,可用于测定盐酸普萘洛尔缓释片中的N-亚硝基普萘洛尔,为盐酸普萘洛尔缓释片的质量控制提供参考。     

手性溶液萃取分离氧氟沙星对映体

目的研究氧氟沙星对映体在手性环境中的萃取分配行为,为外消旋体膜萃取拆分提供理论和设计依据。方法以0.25 mol·L^-1 L-二苯甲酰酒石酸醇溶液为有机相,含0.14 g·L^-1氧氟沙星的0.1 mol·L^-1磷酸氢二钠/磷酸缓冲液为水相,考察了pH对氧氟沙星对映体在水-有机相分配系数(K)和分离因子(α)的影响,研究了不同碳数醇的溶剂化效应,同时运用中空纤维膜对氧氟沙星外消旋体进行初步分离。结果以癸醇为溶剂,pH 6.86时,L-二苯甲酰酒石酸对氧氟沙星外消旋体萃取分配系数大于4.7,α达1.18;用中空纤维支载液膜双有机相逆流分级萃取技术,11个22 cm长膜器串联,产品光学纯度达90%以上。结论L-二苯甲酰酒石酸在醇溶剂中对磷酸氢二钠缓冲液中的RS-氧氟沙星对映体有较强的立体选择性,其中癸醇的效果最好,pH对K和α有较大影响,综合K和α值,取pH 6.86时,手性萃取效果最佳;利用高效中空纤维膜,可使RS氧氟沙星对映体得到不同程度的分离。     

反式曲马多及氧去甲基曲马多对映体跨血脑屏障转运

目的　研究反式曲马多(trans T)及其活性代谢物氧去甲基曲马多(M₁)对映体的跨血脑屏障转运。方法大鼠ip盐酸 trans T (16.7mg·kg^-1 或5.0mg·kg^-1) 1 h后取血、脑脊液和大脑皮层,高效毛细管电泳测定血清、脑脊液和大脑皮层中 trans T和M₁ 对映体的浓度。结果　trans T和M₁ 各对映体浓度以大脑皮层中最高,血清中浓度居中,脑脊液中浓度最低。在血清中,(+)-trans T的浓度明显高于(-)-trans T的浓度,M₁ 两对映体的浓度无明显区别;在脑脊液和大脑皮层中,(+)-trans T的浓度明显高于(-)-trans T的浓度,(+)-M₁ 的浓度明显低于(-)-M₁ 的浓度。结论　trans T和M₁ 的跨血脑屏障转运具有立体选择性,脑组织中分别以(+)-对映体和(-)-对映体浓度较高。     

HPLC和1HNMR分析确定cis-A-和cis-B-羟甲芬太尼的组成和构型

羟甲芬太尼(1)是一个强效的镇痛剂和高亲和、高选择性的阿片μ受体激动剂。通过HPLC和¹HNMR分析,cis-A-l被确定为由等量的cis-(+)-(3R,4S,2'S)-l和:cis-(—)-(3S,4R,2'R)-1组成的外消旋体,cis-B-l被确定为由等量的cis-(—)-(3R,4S,2'R)-1和cis-(+)-(3S/,4R,2'S)-1组成的外消旋体。     

反式曲马朵在大鼠肝微粒体O-去甲基代谢中的立体选择性

目的研究反式曲马朵O-去甲基代谢的立体选择性。方法高效毛细管电泳法测定大鼠肝微粒体孵育液中反式曲马朵和O-去甲基曲马朵对映体的浓度,酶促动力学方法研究O-去甲基曲马朵对映体的生成。结果 (-)-O-去甲基曲马朵生成有较大的V_max;反式曲马朵两对映体间存在相互作用,使(+)-O-去甲基曲马朵生成的V_max明显减慢;奎宁及奎尼丁对(+)-O-去甲基曲马朵生成的抑制作用较强。结论反式曲马朵O-去甲基代谢有立体选择性,对映体间的相互作用及酶抑制剂使其立体选择性程度加强。     

手性衍生化-反相高效液相色谱法测定大鼠肝微粒体中盐酸普罗帕酮对映体及其在代谢研究中的应用

目的　建立鼠肝微粒体中盐酸普罗帕酮消旋体(R/S-PPF)的手性拆分法,以研究大鼠肝微粒体中R/S-PPF体外代谢的立体选择性。方法　用GITC柱前手性衍生化、反相高效液相色谱法拆分R/S-PPF;外标法定量;体外微粒体孵育试验。结果　基线拆分了盐酸普罗帕酮两对映体,容量因子分别为7.9和9.5,分离系数α为1.2,分离度R为1.9,线性范围0.5～320 μg.mL^-1,检测限100 ng.mL^-1,定量限5 μg.mL^-1(RSD<15%)。平均绝对回收率S-PPF为77.1%,R-PPF为76.0%。平均日内、日间精密度均<10%。在DEX和BNF诱导鼠肝微粒体中,PPF的代谢呈显著的立体选择性,在空白对照微粒体中的代谢未呈立体选择性。结论　此法简便、经济,可用于鼠肝微粒体中R/S-PPF代谢的立体选择性研究。     

氢化阿托酸在大鼠体内立体选择性时间药代动力学

以余弦法分析氢化阿托酸(HTA)药代动力学参数证明,下列参数具有昼夜节律:标准明暗周期下,S(+)-HTA的T_1/2β和CL,R(-)-HTA的T_1/2β以及外消旋体的CL和MRT;反相明暗周期下,S(+)-HTA的T_1/2β和AUC,R(-)-体的CL以及外消旋体的CL。下列参数具有立体选择昼夜节律:标准明暗周期下,S(+)-HTA的CL,反相明暗周期下,S(+)-HTA的T_1/2β和AUC以及R(-)-HTA的CL。以外消旋体给药后,大鼠体内由R(-)-体向S(+)-体的转化过程,可出现昼夜节律,在两种明暗周期下,峰值相位均位于黑暗期之末,据此,提出HTA的清晨给药治疗方案。     

普萘洛尔光学异构体在经不同诱导剂诱导的大鼠肝微粒体P450系统中的代谢特征

采用正常及β萘黄酮（BNF）或苯巴比妥（PB）诱导的大鼠肝微粒体,研究了R(+)和S(-)普萘洛尔代谢酶动力学参数及立体选择性. 实验表明,3种微粒体酶的亲和力均无立体选择性,反应速度有较大差别,并表现出立体选择性. BNF组对两种对映体的催化作用较对照组增强,并对R(+)对映体有选择性;PB组的催化作用较对照组减弱,但对S(-)对映体有选择性. 实验结果提示普萘洛尔经细胞色素P450代谢时,酶活性中心的结合基团无立体选择性,而催化基团具有立体选择性.     

Stereoselectivity and interaction between the glucuronidation of S-(-)- and R-(+)-propranolol in rat hepatic microsomes pretreated with different inducers

Phase II glucuronidation metabolism of side-chain propranolol was studied using microsomes from rats treated with the inducers beta-naphthoflavone (BNF) or dexamethasone (Dex). The glucuronide concentrations of propranolol enantiomers were assayed by RP-HPLC. The kinetic constants of glucuronidation, Km, Vmax and Clint were determined. There are significant differences between the R- and S-enantiomeric glucuronide in Km, Vmax and Clint P < 0.05, P < 0.01 and P < 0.05 in control microsome. There are significant differences in Km and Clint (P < 0.01 or P < 0.001) but no significant differences in Vmax (P > 0.05) between R and S-enantiomeric glucuronide in the microsomes induced with Dex and BNF. The formation of S-(-)-propranolol glucuronide was inhibited by R-(+)-propranolol from the rat microsomes pretreated with BNF and Dex. The glucuronidation metabolism of propranolol enantiomers exhibited the stereoselectivity in rat hepatic microsomes induced with BNF or Dex. Multiple UGT1A and 2B may be involved in stereoselective O-glucuronidation of propranolol enantiomers in rat liver microsomes. The glucuronides produced were in favor of the R-enantiomer. There is an interaction between the glucuronidation of R- and S-enantiomer.     

Species differences for stereoselective metabolism of ethofumesate and its enantiomers in vitro

1. The stereoselective metabolism of ethofumesate (ETO) and its enantiomers in rabbit and rat liver microsomes have been studied by chiral high-performance liquid chromatography (HPLC) method. Two metabolites were detected in both liver microsomes in the presence of β-nicotinamide adenine dinucleotide phosphate (NADPH).

2. The T_1/2 of (+)-ETO and (?)-ETO in rabbit liver microsomes were 12.2 and 4.7?min of rac-ETO and 25.9 and 6.7 of ETO enantiomers. However, the T_1/2 of (+)-ETO and (?)-ETO in rat liver microsomes were 5.3 and 5.9?min of rac-ETO and 7.8 and 10.6 of ETO enantiomers. The stereoselective selectivity is similar to the in vivo study.

3. After incubation of ETO enantiomers, stereoselectivity was present in the formation of ETO-OH enantiomer in rabbit liver microsomes, but stereoselectivity was not evident in rat liver microsomes.

4. There was no chiral inversion from the (+)-ETO to (?)-ETO or inversion from (?)-ETO to (+)-ETO in both rabbit and rat liver microsomes.

     

Effect of Probenecid on the Enantioselective Pharmacokinetics of Oxprenolol and Its Glucuronides in the Rabbit

Purpose. To study the effect of probenecid on the stereoselective pharmacokinetics of oxprenolol and its glucuronides in the rabbit. Methods. An oral dose of 50 mg/kg racemic oxprenolol was given to nine rabbits twice, in random sequence with and without the concurrent administration of probenecid. Oxprenolol enantiomers were determined in plasma and urine by an enantioselective HPLC method. Oxprenolol glucuronides were measured in plasma and urine after enzymatic hydrolysis. Results. The disposition of the oxprenolol enantiomers in rabbits is stereoselective, mainly due to a difference in metabolism. Renal excretion is only a minor elimination route for unchanged oxprenolol, and the renal clearances of the enantiomers are similar. Pre-treatment with probenecid did not affect the plasma concentrations of the oxprenolol enantiomers, but there was a slight decrease in their urinary excretion. The plasma concentrations of the oxprenolol glucuronides are much higher than those of the parent enantiomers, and those of (S)-glucuronide are about twice those of its antipode. About 10% of the oxprenolol dose is excreted in the urine as glucuronides. The renal clearances of both glucuronides are similar, and markedly higher than the creatinine clearance. After probenecid, the mean glucuronide plasma levels were markedly higher, with for both glucuronides a more than twofold increase in mean AUC. Probenecid decreased the renal clearance of both glucuronides to about 30%. Moreover, it decreased slightly the formation clearance of (S)-glucuronide, while the formation clearance of (R)-glucuronide was not significantly influenced. Conclusions. Our results show that in the rabbit, both oxprenolol glucuronide diastereomers are actively secreted by the kidney, and that this process is inhibited by probenecid.     

盐酸普萘洛尔缓释片与常释片的生物利用度比较研究

目的：通过双交叉试验证明盐酸普萘洛尔缓释片有缓释作用。方法：用HPLC方法,测定血清中普萘洛尔浓度,进行盐酸普萘洛尔缓释片与常释片的生物利用度比较及峰谷浓度波动研究。结果：12位健康男性受试者一次交叉口服缓释片和常释片(均为40 mg)后的C_max分别为62.4±23.3和95.9±12.6 ng.mL^-1,AUC分别为360.2±80.6和383.5±74.2 ng.h.mL^-1,缓释片相对于常释片的相对生物利用度为95%;12位受试者连续服缓释片和常释片后平均稳态浓度分别为42.2±12.2和32.7±7.1 ng.mL^-1,波动度(DF)分别为0.90±0.35和2.09±0.34。结论：两种制剂具生物等效性,且缓释片比常释片有峰谷浓度差异小、血药浓度波动幅度小的特点。     

Glucuronidation of the enantiomers of E-10-hydroxynortriptyline in human and rat liver microsomes

Conjugation of racemic E-10-hydroxynortriptyline (E-10-OH-NT) with glucuronic acid was studied in the liver microsomal fraction of rats and humans. The diastereomeric glucuronides of E-10-OH-NT were resolved and quantitated by HPLC. Only the (+)-enantiomer was glucuronidated in liver microsomes from humans. Rat liver microsomes catalyzed the formation of both glucuronides. Phenobarbital pretreatment of rats increased the glucuronidation of both enantiomers about five-fold. The formation rate of (+)-E-10-OH-NT glucuronide varied from 5.5 to 33.2 pmol/mg x min, in microsomes from 13 humans. High activity was found in individuals previously treated with pentobarbital. Inhibition experiments with human liver microsomes showed that amitriptyline is a potent competitive inhibitor of (+)-E-10-OH-NT glucuronidation. p-Nitrophenol, paracetamol and 2-hydroxydesipramine also inhibited this reaction.     

Preclinical factors affecting the pharmacokinetic behaviour of tanshinone IIA,an investigational new drug isolated from Salvia miltiorrhiza for the treatment of ischaemic heart diseases

Tanshinone IIA (TSIIA) is a major active triterpenoid isolated from Salvia miltiorrhiza. The purposes of this study were to investigate various preclinical factors that determined the pharmacokinetics of TSIIA. After oral dosing at 6.7, 20, and 60 mg kg^?1, TSIIA was detected mainly as glucuronidated conjugate (TSIIAG) with only small amounts of the unchanged in the plasma. TSIIA was predominantly excreted into the bile and faeces as TSIIAG, and urine to a minor extent. The C_max and AUC_0?t of TSIIAG after i.p. administration were significantly lower than those after intragastric administration. The plasma concentration–time profiles of TSIIA following oral dosing of TSIIA showed multiple peaks. The C_max and AUC_0?t of TSIIA and its glucuronides in rats with intact bile duct were significantly lower than those of rats with bile duct cannulation. Studies from the linked-rat model and intraduodenal injection of bile containing TSIIA and its metabolites indicate that TSIIA glucuronides underwent hydrolysis and the aglycone was reabsorbed from the gut and excreted into the bile as conjugates. TSIIA had a wide tissue distribution, with a very high accumulation in the lung, but very limited penetration into the brain and testes. TSIIA was metabolized by rat CYP2C, 3A and 2D, as ticlopidine, ketoconazole and quinidine all inhibited TSIIA metabolism in rat liver microsomes. Taken collectively, these findings indicate that multiple factors play important roles in determining the pharmacokinetics of TSIIA.     

Direct determination of diastereomeric carprofen glucuronides in human plasma and urine and preliminary measurements of stereoselective metabolic and renal elimination after oral administration of carprofen in man

A direct stereospecific HPLC assay for carprofen glucuronides in biologic fluids was developed that makes use of a reverse phase (C 18) gradient system, in which the mobile phase consisted of a mixture of acetonitrile and tetrabutylammonium hydroxide buffer (pH 2.5). Reference diastereomeric glucuronides of carprofen were purified from human urine after oral administration of the single enantiomers. When 0.1 ml of sample was used, the limit of detection for carprofen glucuronides was 50 ng/ml in plasma and 200 ng/ml in urine. Coefficients of variation did not exceed 12% for both intra and interday variability. This HPLC method is applicable to pharmacokinetic analysis for carprofen glucuronides in humans. After oral administration of the single enantiomers there was little indication of metabolic inversion. For the two enantiomers the apparent total and metabolic clearances were similar. The limited data available suggest that renal clearance of the (S)-glucuronide was greater than that of the (R)-glucuronide.     

Selective Effect of Adjuvant Arthritis on the Disposition of Propranolol Enantiomers in Rats Detected Using a Stereospecific HPLC Assay

Nonstereospecific studies have indicated that the pharmacokinetics of propranolol (PR) are altered in inflammatory conditions such as arthritis. However, as the kinetics and dynamics of PR are stereoselective, we examined the effect of adjuvant arthritis (AA) on the disposition of the individual enantiomers. A novel normal-phase stereospecific HPLC assay for PR was developed involving chiral derivatization with S-(naphthyl)ethyl isocyanate and fluorescence detection. Oral and iv doses of racemic PR were administered to control and AA rats (n = 6). AA had no significant effect on either clearance or S:R ratio after iv doses. On the other hand, after oral doses, clearance was significantly decreased in AA. Although significant for both enantiomers, this effect was more pronounced on the less active R-enantiomer. The AUC R:S ratio was, therefore, significantly altered (AA, 14 ± 3.0; control, 4.3 ± 1.2). Increased total (S + R) plasma concentrations of PR in AA, possibly due to a reduced intrinsic clearance, therefore, reflect mainly increased concentrations of the less active R-enantiomer.     

人肝微粒体中尼莫地平及其脱氢代谢物的HPLC测定法及代谢动力学

目的：建立人肝微粒体中尼莫地平及其代谢物的HPLC测定法,并用本法研究尼莫地平在肝微粒体中代谢的动力学。方法：采用HPLC法,色谱柱为Hypersil C₁₈柱,流动相为乙腈—水(62∶38)检测波长UV 238 nm,样品用乙醚—正己烷(1∶1)提取。结果：本法的回收率为94.3%～98.5%,日内和日间RSD为1.45%～9.68%,尼莫地平和其脱氢代谢物的浓度分别在1.31～20.92 μg.mL^-1和122.7～4908.0 ng.mL^-1范围内与峰面积呈良好线性关系。在本实验条件下尼莫地平呈线性消除,而其脱氢代谢物呈线性增加。结论：尼莫地平在人肝微粒体内被迅速代谢,肝微粒体P450酶参与了尼莫地平的脱氢氧化。