在大鼠肝微粒体中反式曲马朵和反式氧去甲基曲马朵对映体代谢的性别差异

目的研究反式曲马朵(trans T)对映体代谢，反式氧去甲基曲马朵(Ml)对映体生成及其与葡糖醛酸结合的性别差异。方法以trans T或Ml为底物分别与大鼠肝微粒体孵育，高效毛细管电泳法测定孵育液中trans T和Ml对映体。结果与(+)-对映体相比，(-)-trans T优先代谢，(-)-Ml优先生成。在雌性大鼠肝微粒体中(-)-Ml优先与葡糖醛酸结合；Ml两对映体生成及其与葡糖醛酸结合的CL_int比值偏离1的程度较大。在雄性大鼠肝微粒体中(+)-Ml优先与葡糖醛酸结合。结论Trans T代谢，M1生成及其与葡糖醛酸结合均具立体选择性和性别差异；Ml生成及其与葡糖醛酸结合立体选择性的程度以雌性大鼠的较高。     

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Vmax;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Vmax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.     

反式曲马朵和反式氧去甲基曲马朵在大鼠胆汁中排泄的立体选择性

目的研究反式曲马朵(trans T)及反式氧去甲基曲马朵(M1)在大鼠胆汁中排泄的立体选择性. 方法高效毛细管电泳法测定大鼠iv trans T或 M1后胆汁和血浆中trans T, M1和与葡糖醛酸结合M1(M1c)的对映体.结果大鼠iv trans T后,胆汁中(+)-trans T水平较(-)-trans T高,(+)/(-)-trans T较血浆中(+)/(-)-trans T的比值小.大鼠iv M1后,胆汁中(+)-M1水平较(-)-M1高,(+)-M1c较(-)-M1c低,(+)-M1与葡糖醛酸的结合率较(-)-M1低.结论 Trans T和M1在大鼠胆汁中排泄具立体选择性,(+)-trans T和(-)-M1被优先排泄.     

人体内反式曲马朵及其活性代谢产物反式氧去甲基曲马朵对映体的药物动力学(英文)

目的:研究反式曲马朵(trans-T)及其活性代谢产物反式氧去甲基曲马朵(M1)的人体药代动力学立体选择性。方法:12名健康男性受试者口服多剂量盐酸trans-T缓释片后,采用高效毛细管电泳(HPCE)法测定血清中trans-T及M1对映体的浓度。结果:血清中trans-T对映体浓度达稳态后,不同时间血清中( )-trans-T的浓度均高于(-)-trans-T的浓度,两对映体除T_(max)以外的药代动力学参数的差异均有显著性。在大多数受试者体内和大多数取血时间点,(-)-M1的浓度高于( )-M1的浓度;在不同受试者体内,血清中M1对映体浓度的比值差别较大,两对映体的C_(max)和C_(min)差异有显著性。结论:trans-T和M1具有药代动力学立体选择性。人体对( )-trans-T比对(-)-trans-T吸收完全,消除慢;在不同受试者体内,M1的药代动力学立体选择性是不同的。     

反式曲马朵和反式氧去甲基曲马朵在大鼠胆汁中排泄的立体选择性反式曲马朵和反式氧去甲基曲马朵在大鼠胆汁中排泄的立体选择性

目的研究反式曲马朵(trans T)及反式氧去甲基曲马朵(M1)在大鼠胆汁中排泄的立体选择性。方法高效毛细管电泳法测定大鼠iv trans T或 M1后胆汁和血浆中trans T, M1和与葡糖醛酸结合M1(M1_c)的对映体。结果大鼠iv trans T后,胆汁中(+)-transT水平较(-)-trans T高,(+)/(-)-trans T较血浆中(+)/(-)-trans T的比值小。大鼠iv M1后,胆汁中(+)-M1水平较(-)-M1高,(+)-M1_c较(-)-M1_c低,(+)-M1与葡糖醛酸的结合率较(-)-M1低。结论trans T和M1在大鼠胆汁中排泄具立体选择性,(+)-trans T和(-)-M1被优先排泄。     

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。     

反式曲马朵及反式氧去甲基曲马朵对映体在大鼠中枢神经系统的分布

目的：研究反式曲马朵（trans-T)及其活性代谢产物反式氧去甲基曲马朵（M1）对映体的中枢神经系统分布。方法：大鼠ip单剂量的盐酸trans-T或M1后,采用高效毛细管电泳（HPCE）法测定血清和不同脑组织中trans-T及M1对映体的浓度,脑组织包括脑脊液、大脑皮层、纹状体、下丘脑、小脑、延髓。结果：大鼠ip盐酸trans-T后,在血清及所有测试脑组织中,（＋）－trans-T的浓度均高于（－）－trans-T的浓度;在所有测试脑组织中,（＋）－M1的浓度均低于（－）－M1的浓度;trans-T和（＋）－M1对映体的浓度以大脑皮层中最高,脑脊液中最低。大鼠ip M1后,在血清及所有测试脑组织中,（＋）－M1的浓度均高于（－）－M1的浓度;M1对映体的浓度以大脑皮层中最高,脑脊液中最低。结论：在血清和不同脑组织中,trans-T及M1对映体的浓度是有区别的;trans-T及M1在中枢神经系统的分布具有立体选择性;大鼠ip M1与trans-T后,M1在中枢神经系统分布的立体选择性是不同的。     

盐酸反式曲马朵口服制剂中盐酸曲马朵立体异构体的分离与测定

目的 :建立盐酸反式曲马朵口服制剂中盐酸曲马朵 4种立体异构体的分离测定方法。方法 :采用高效毛细管电泳法 ,未涂层毛细管 75 μm× 37cm (有效长度 30cm) ;分离介质为 40mmol·L-1Tris缓冲液 (pH 2 5 ) ,内含 0 8mmol·L-1磺丁基 - β-环糊精 ;分离电压 15kV ,柱温 2 5℃ ,检测波长 2 14nm ;进样电压 10kV ,2 0s ,入口为阳极。 结果 :以 (- ) -氧去甲基曲马朵为内标 ,反式曲马朵、顺式曲马朵的对映体达到基线分离 ,( ) -盐酸反式曲马朵、 (- ) -反式曲马朵的线性浓度范围为 0 5～ 1 5 μg·mL-1;4种制剂中 ( ) -盐酸反式曲马朵和 (- ) -盐酸曲马朵平均回收率 96 87%～10 2 4%和 96 2 8%～ 10 1 3 % ,RSD <5 % ,n =5 ;盐酸曲马朵 4种立体异构体的最低检测浓度为 5ng·mL-1;4种盐酸反式曲马朵口服制剂中盐酸顺式曲马朵各对映体含量不超过 0 12 % ,盐酸反式曲马朵各对映体的含量为标示量的 45 5 8%～5 0 93 %。结论 :本方法可用于盐酸反式曲马朵口服制剂中盐酸顺式曲马朵对映体的限量检查和盐酸反式曲马朵对映体的含量测定     

反式曲马朵及其活性代谢产物反式氧去甲基曲马朵肾脏清除的立体选择性

目的:研究反式曲马朵及其活性代谢物反式氧去甲基曲马朵肾脏清除的立体选择性.方法:取雄性SD大鼠的右肾,分别以含反式曲马朵(300μg/L)或反式氧去甲基曲马朵(50μg/L)的灌流液(10mL)进行灌流;利用高效毛细管电泳法测定灌流后灌流液、尿液中反式曲马朵及反式氧去甲基曲马朵对映体的浓度,并计算对映体浓度比值.结果:以反式曲马朵进行离体肾灌流后,在灌流液中,( )-反式曲马朵的浓度高于(-)-反式曲马朵的浓度,( )-反式氧去甲基曲马朵的浓度低于(-)-反式氧去甲基曲马朵的浓度;在尿液中,( )-反式曲马朵较(-)-反式曲马朵多,( )-反式氧去甲基曲马朵较(-)-反式氧去甲基曲马朵少.以反式氧去甲基曲马朵灌流后,在灌流液中( )-反式氧去甲基曲马朵的浓度低于(-)-反式氧去甲基曲马朵的浓度;在尿液中( )-反式氧去甲基曲马朵较(-)-反式氧去甲基曲马朵高.结论:反式曲马朵及反式氧去甲基曲马朵的肾脏清除具有立体选择性.在肾脏中反式曲马朵的氧去甲基代谢具有立体选择性,以(-)-反式曲马朵优先代谢成(-)-反式氧去甲基曲马朵.反式氧去甲基曲马朵的尿排泄具有立体选择性,以( )-反式氧去甲基曲马朵占优.     

反式曲马朵在大鼠小肠中吸收的立体选择性

目的研究反式曲马朵(Trans T)在大鼠小肠中吸收的立体选择性。方法高效毛细管电泳法测定小肠分段灌流液中Trans T对映体的浓度。结果Trans T对映体在小肠不同部位的吸收分数基本一致;在低浓度时(+)-Trans T的吸收分数明显低于(-)-Trans T;在高浓度时Trans T对映体的吸收分数降低,(+)-Trans T与(-)-Trans T的吸收分数无明显差别。结论Trans T在大鼠小肠的不同部位均能被吸收,具立体选择性,以(-)-Trans T占优。     

在大鼠体内反式曲马朵及其活性代谢物反式氧去甲基曲马朵对映体药代动力学的性别差异

AIM: To compare the pharmacokinetics of the enantiomers of trans-tramadol (trans-T) and its active metabolite,trans-O-demethyltramadol (M1), in male and female rats. METHODS: Following a single oral dose of 10 mg/kg trans-T hydrochloride to rats, ( )-trans-T, (-)-trans-T, ( )-M1, and (-)-M 1 in plasma were determined by a high performance capillary electrophoresis method. RESULTS: The females showed higher plasma concentrations of ( )-trans-T, (-)-trans-T, and ( )-M1 than the males. The enantiomers of trans-T were absorbed and eliminated more slowly in the females than in the males. ( )-M1 was eliminated more slowly in the females than in the males.All pharmacokinetic parameters but Tmax of the two enantiomers of trans-T were significantly different in both sex rats. The ( )/(-)-enantiomeric ratios of the pharmacokinetic parameters for trans-T in the males were similar to those in the females. The values of Cmax, AUC0-∞ of the two enantiomers of M1 were significantly different in both sex rats. The ( )/(-)-enantiomeric ratios of Cmax, AUC0-∞ for M 1 were lower than 1 in the males, larger than 1 in the females. CONCLUSIONS: Systemic exposure of ( )-trans-T, (-)-trans-T, and ( )-M 1 was higher in female rats than in male rats. The stereoselectivity in pharmacokinetics of trans-T was similar, and that of M 1 was different in male and female rats.     

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.     

Role of CYP3A4 and CYP2C19 in the stereoselective metabolism of lansoprazole by human liver microsomes

OBJECTIVE: The aim of this investigation was to clarify the stereoselective properties in lansoprazole metabolism by monitoring the metabolic consumption for each enantiomer and the formation of the main metabolites, lansoprazole sulfone and 5-hydroxylansoprazole, in the presence of human liver microsomal enzymes. METHODS: Human liver microsomes or recombinant cytochrome P450 (CYP) enzymes were incubated with either (+/- )-, (+)-, or (-)-lansoprazole in the presence of reduced nicotinamide adenine dinucleotide phosphate. The metabolic consumption of lansoprazole enantiomers was estimated from the amounts of enantiomers consumed by microsomal enzymes after incubation at 37 degrees C for 60 min. Metabolites of lansoprazole, lansoprazole sulfone, and 5-hydroxylansoprazole were determined after incubation at 37 degrees C for 20 min, and kinetic parameters [Michaelis constant (Km) and maximum velocity (Vmax)] were obtained using Eadie-Hofstee plots. RESULTS: (-)-Lansoprazole was metabolized more preferentially than (+)-lansoprazole in human liver microsomes. Stereoselective sulfoxidation and hydroxylation [(+) > (-)] were observed in human liver microsomes. Strikingly, in sulfoxidation, a significantly higher intrinsic clearance (Vmax,l/Km,l) of (-)-lansoprazole (0.023 +/- 0.001 ml/min/mg) than (+)-lansoprazole (0.006 +/- 0.000 ml/min/mg) was observed. Consequently, sulfoxidation is likely to play an important role in the stereoselective metabolism of lansoprazole enantiomers. P450-isoform specificity for each enantiomer was evident. CYP3A4, which mainly catalyzed sulfoxidation, was more active toward (-)-lansoprazole in either a chiral or racemic drug as a substrate. CYP2C19, which catalyzed hydroxylation, preferentially metabolized (+)-lansoprazole. The consumption of (+)-lansoprazole was markedly inhibited by (-)-lansoprazole, indicating a metabolic enantiomer/enantiomer interaction. However, this alteration of recombinant CYP2C19 specificity for (+)-lansoprazole did not appear in metabolism in human liver microsomes. CONCLUSIONS: Stereoselective metabolism was observed in human liver microsomes, and this stereoselectivity was mainly based on CYP3A4 specificity for preferable metabolism of (-)-lansoprazole.     

Influence of substrate configuration on chlorpheniramine N-demethylation by hepatic microsomes from rats, rabbits, and mice

Measurements of formaldehyde formation in parallel incubations containing either (S)-(+)- or (R)-(-)-chlorpheniramine (CPA) and rat liver microsomes demonstrated that the active antihistamine, (S)-(+)-CPA, is N-demethylated about 35% faster than the inactive (R)-(-)-enantiomer. The KM values for the enantiomers were the same. Phenobarbital pretreatment increased Vmax values without affecting the stereoselectivity. N-Demethylation occurred at a several-fold faster rate with rabbit than with rat liver microsomes, but stereoselectivity was the same. N-Demethylation of CPA enantiomers were studied in microsomes prepared from each of four inbred strains of mice. These experiments demonstrated that stereoselectivity is species-dependent, as no significant differences in metabolism rates of CPA enantiomers could be detected with these microsomes. Pseudoracemic mixtures containing equal quantities of deuterated (S)-(+)-CPA and unlabeled (R)-(-)-CPA were incubated with microsomes from three species. Formation of the enantiomers of N-desmethyl- and N,N-didesmethyl-CPA (DMCPA and DDMCPA, respectively) were measured by GC/MS techniques. With microsomes from rats and mice, the ratio of (S)-DMCPA to (R)-DMCPA was essentially the same as that determined by measuring the formaldehyde formed in separate incubations of (S)-(+)- or (R)-(-)-CPA. Stereoselectivity with rabbit liver microsomes and pseudoracemic CPA was substantially higher than that determined in incubations with the separate enantiomers. The results suggest either that (S)-(+)-CPA inhibits the N-demethylation of (R)-(-)-CPA under these conditions, or that DMCPA undergoes further biotransformation by a route(s) which is stereoselective, favoring the (R)-enantiomer. Formation of DDMCPA could only be detected with rabbit microsomes and was found to occur with approximately the same stereoselectivity as that determined for the formation of DMCPA.     

外消旋普罗帕酮在经诱导的大鼠肝微粒体中N-去丙基化的立体选择性

采用对照及β-萘黄酮(β-NF)或地塞米松(Dex)诱导的大鼠肝微粒体,应用GITC柱前衍生化,反相高效液相色谱法研究了消旋普罗帕酮〔(R/S)-PPF〕体外代谢的立体选择性. 实验结果表明,在Dex,β-NF诱导的微粒体中有N-去丙基普罗帕酮生成。在β-NF,Dex预处理组,(R/S)-PPF低浓度时的经肝微粒体代谢具有立体选择性,R(-)对映体的清除大于S(+)对映体,高浓度时的代谢无立体选择性. R(-)对映体的K_m值显著低于S(+)对映体,而V_max值无显著性差异. 在Dex预处理组中的立体选择性大于β-NF组. 在对照组中代谢无立体选择性,且K_m,V_max值均小于β-NF,Dex预 处理组。结果提示,CYP1A,CYP3A4亚族对普罗帕酮(PPF)的N-去丙基化有贡献. (R/S)-PPF的N-去丙基化具有浓度依赖性的立体选择性.     

Human liver morphine UDP-glucuronyl transferase enantioselectivity and inhibition by opioid congeners and oxazepam.

1. Morphine uridine diphosphate glucuronyl transferase (UDP-GT) was studied in human liver microsomes. The (-)- and (+)-morphine enantiomers were used as substrates and inhibitors, such as oxazepam and various opioid congeners were employed to characterize the different glucuronidation pathways. The kinetics of the oxazepam inhibition were studied in the rat liver. 2. The overall glucuronidation of (+)-morphine was higher than that of (-)-morphine. The morphine congeners tested, potently inhibited the formation of (-)-morphine-3-glucuronide ((-)-M3G), except for normorphine and codeine. The formation of (+)-morphine-6-glucuronide [+)-M6G) was potently inhibited by only dextromethorphan and (+)-naloxone. All drugs except normorphine inhibited the formation of (+)-M3G by 18-50%. 3. The metabolism of (-)-morphine to (-)-M3G was more sensitive to oxazepam inhibition than the formation of (+)-M3G from (+)-morphine in the rat liver. 4. The glucuronidation of natural morphine is subject to in vitro interaction with oxazepam and several opiate drugs. Our study supports the theory of more than one type of UDP-GT being involved in morphine glucuronidation.