高效毛细管电泳法同时测定维拉帕米和去甲维拉帕米对映体的血浆浓度

用高效毛细管电泳中最常用的毛细管区带电泳模式,以三甲基-β-环糊精(TM-β-CD)为手性选择剂,同时测定维拉帕米和去甲维拉帕米对映体的血浆浓度。手性测定条件:手性拆分缓冲液为含60mmol·L^-1TM-β-CD(pH2.5),浓度60mmol·L^-1的磷酸盐缓冲液;毛细管柱为30cm×75μm(ID)的聚丙烯酰胺涂渍柱;选择电迁移方式进样,电压12kV,时间7s;运行电压14kV;紫外检测波长200nm;设柱温为20℃;12min内完成检测。各对映体检测的线性范围为2.50ng·ml^-1～300.0ng·ml^-1,准确度和精密度达到生物样品分析的要求。用本法测定健康志愿者口服和静滴VPM后各对映体的血浆浓度,结果良好。     

Drug interaction between oral atorvastatin and verapamil in healthy subjects: effects of atorvastatin on the pharmacokinetics of verapamil and norverapamil

Aim It has been reported that verapamil and atorvastatin are inhibitors of both P-glycoprotein (P-gp) and microsomal cytochrome P450 (CYP) 3A4, and verapamil is a substrate of both P-gp and CYP3A4. Thus, it could be expected that atorvastatin would alter the absorption and metabolism of verapamil. Methods The pharmacokinetic parameters of verapamil and one of its metabolites, norverapamil, were compared after oral administration of verapamil (60 mg) in the presence or absence of oral atorvastatin (40 mg) in 12 healthy volunteers. Results Pharmacokinetics of verapamil were significantly altered by the coadministration of atorvastatin compared with those of without atorvastatin. For example, the total area under the plasma-concentration time curve to the last measured time, 24 h, in plasma (AUC_{0−24 h}) of verapamil increased significantly by 42.8%. Thus, the relative bioavailability increased by the same magnitude with atorvastatin. Although the AUC_{0−24 h} of norverapamil was not significantly different between two groups of humans, the AUC_{0−24 h, norverapamil}/ AUC_{0−24 h, verapamil} ratio was significantly reduced (27.5% decrease) with atorvastatin. Conclusion The above data suggest that atorvastatin could inhibit the absorption of verapamil via inhibition of P-gp and/or the metabolism of verapamil by CYP3A4 in humans.     

齐墩果酸对大鼠体内细胞色素P450酶活性的影响

目的：研究齐墩果酸对大鼠体内细胞色素P450酶CYP3A4的影响。方法：用Cocktail探针药物法,将SD大鼠按体重随机分组,分别给予0．5％CMC—Na、齐墩果酸高剂组、中剂组和低剂组灌胃9天,第10天给药1h后,灌胃给药维拉帕米,不同时间点采集血样,用LC—MS／MS法测定血浆中探针药物维拉帕米及其代谢产物去甲维拉帕米的浓度,用PKSolution软件估算其药代动力学参数。结果：连续灌胃给药齐墩果酸10天,维拉帕米和去甲维拉帕米药动学参数Cmax、AUC显著减小（P〈0．01）。结论：连续灌胃给药齐墩果酸10天,对CYP3A4酶活性有显著诱导作用。     

Multiple dose comparison of a whole 240 mg verapamil sustained-release tablet with two half tablets

Twelve healthy male volunteers were studied in a balanced crossover comparison of an intact 240 mg verapamil sustained-release tablet (Securon SR, Isoptin Forte Retard) given once daily for 7 days, and the same dose given as two half tablets. One subject was withdrawn because of asymptomatic second degree heart block on day 3 of verapamil treatment. The mean Cmax after dosing with whole tablets, 143 (95 per cent confidence limits 91.6-223) ng ml-1 was lower than after dosing with half tablets, 160 (107-241) ng ml-1, but this was not significant (p = 0.49). The mean steady-state Cmin values after whole and half tablets were also similar: 22.2 (12.6-39.4) ng ml-1 and 22.0 (16.2-29.9) ng ml-1, respectively (p = 0.96). The mean (+/- S.D.) tmax, AUC0-24 and t 1/2 were not significantly different: whole tablet 3.5 +/- 1.2 h, 1733 +/- 1125 ng.h ml-1 and 10.5 +/- 3.4 h, respectively, and half tablets 3.6 +/- 1.0 h, 1780 +/- 1057 ng.h ml-1 and 9.6 +/- 2.3 h, respectively. The findings for plasma norverapamil were generally similar to those for the parent drug. This investigation indicates that the formulation is sufficiently robust to retain its sustained-release properties when the tablet is halved.     

Pharmacokinetics of verapamil and its major metabolite, nor-verapamil from oral administration of verapamil in rabbits with hepatic failure induced by carbon tetrachloride

The aim of this study was to investigate the pharmacokinetic changes of verapamil and its major metabolite, norverapamil, after oral administration of verapamil (10 mg/kg) in rabbits with slight, moderate and severe hepatic failure induced by carbon tetrachloride. The plasma verapamil concentrations in all groups of hepatic failure were significantly higher (p < 0.01) than the control. However, the plasma norverapamil concentrations in severe hepatic failure were significantly higher (p < 0.05) than the control. The peak concentrations (Cmax) and the areas under the plasma concentration-time curve (AUC) of verapamil in the rabbits were significantly (p<0.01) higher than the control. The absolute bioavailability (F(A.B)) and the relative bioavailability (F(R.B)) of verapamil in the rabbits with hepatic failure were significantly higher (13.6-22.2% and 150-244%, respectively) than the control (9.1% and 100%, respectively). Although the AUC and Cmax of its major metabolite, norverapamil, in slight, moderate hepatic failure were not significantly lower than the control, the metabolite-parent AUC ratio in all groups of hepatic failure was decreased significantly (p < 0.05, in slight group; p < 0.01, in moderate and severe group) than the control. This could be due to decrease in metabolism of verapamil in the liver because of suppressed hepatic function in the hepatic failure groups because verapamil is mainly metabolized in the liver. From our data, it would seem appropriate that in patients with liver disease, doses of verapamil should be decreased by degree of hepatic failure.     

Enhanced bioavailability of verapamil after oral administration with hesperidin in rats

The aim of this study was to investigate the effects of hesperidin on the pharmacokinetics of verapamil and its major metabolite, norverapamil, in rats. The pharmacokinetic parameters of verapamil and norverapamil in rats were measured after the oral administration of verapamil (9 mg/kg) in the presence or absence of hesperidin (3 or 10 mg/kg). Compared to the control group, the presence of hesperidin significantly (p<0.01) increased the area under the plasma concentration-time curve (AUC) of verapamil by 71.1–96.8% and the peak concentration (C_max) of verapamil by 98.3–105.2%. Hesperidin significantly (p<0.01) decreased the total plasma clearance (CL/F) of verapamil by 41.6–49.2% in rats. However there was no significant change in the time to reach the peak plasma concentration (T_max), the elimination rate constant (K_el) and the terminal half-life (T_1/2) of verapamil in the presence of hesperidin. The AUC and C_max of norverapamil were significantly (p<0.05) higher in rats coadministrated with hesperidin than those of the control. Consequently hesperidin significantly enhanced bioavailability of verapamil in rats. These results might be due to the decreased efflux and metabolism of verapamil in the intestine. Drug interactions should be concerned in the clinical setting when verapamil is used concomitantly with hesperidin or hesperidin-containing dietary.     

毛细管区带电泳同时分离维拉帕米和去甲维拉帕米对映体

目的 :建立同时分离维拉帕米 ( VPM )和去甲维拉帕米 ( NVPM )对映体的高效毛细管电泳方法。　 方法 :采用毛细管区带电泳模式 ,以三甲基 -﹀-环糊精 ( TM-﹀- CD )为手性选择剂 ,考察了毛细管柱、进样方式、运行电压、缓冲液 p H值、溶剂等因素对峰迁移、分辨率、灵敏度的影响 ,选择优化的电泳条件用于标准溶液的分离和测定。　 结果 :用 p H为 2 .5,含 60 mmol/ LTM-﹀- CD的 60 mmol/ L磷酸盐缓冲液为手性拆分剂 ,在 30 cm× 75︼m ( id)的聚内酰胺涂渍柱(柱温 2 0℃ )上 ,采用 12 k V( 7s)电迁移进样 ,运行电压为 14k V,紫外检测波长 2 0 0 nm,能在 11min内将内标 ( Gallopamil)、R- VPM、S- VPM、R- NVPM和 S- NVPM完全分离 ,并用各对映体与内标的峰面积比为定量指标进行水标溶液的浓度测定 ,定量检测限为 2 5ng/ ml,日间变异小于10 % ,线性关系良好。　 结论 :毛细管区带电泳方法能快速、高效地分离 VPM和 NVPM对映体 ,为 VPM和 NVPM对映体的测定及质量控制提供新的方法 ,为生物体液中 VPM及其代谢物NVPM对映体的测定、为开展 VPM对映体特异性的药代动力学和药效学研究打下基础     

Effect of pioglitazone on the pharmacokinetics of verapamil and its major metabolite,norverapamil, in rats

Pioglitazone, a thiazolidinedione antidiabetic drug, inhibits cytochrome P450 (CYP) 2C8 and CYP3A4 enzymes in vitro. This study investigated the effect of pioglitazone on the pharmacokinetics of verapamil and its major metabolite, norverapamil, in rats, after oral administration of verapamil (9 mg/kg) in the presence or absence of pioglitazone (0.3 or 1.0 mg/kg). Pioglitazone altered verapamil pharmacokinetics compared with verapamil alone. The presence of 1.0 mg/kg of pioglitazone significantly (p < 0.05) increased the area under the plasma concentration-time curve (AUC) and the peak concentration (C(max)) of verapamil by 49.0% and 46.8%, respectively, and significantly (p < 0.05) decreased the total plasma clearance (CL/F) of verapamil by 32.8%. The metabolite-parent AUC ratio in the presence of pioglitazone (1.0 mg/kg) significantly (p < 0.05) decreased by 21.9% compared to the control group. Thus, coadministration of pioglitazone inhibited the CYP3A4-mediated metabolism of verapamil.     

高效液相色谱法同时测定盐酸维拉帕米及其主要代谢产物

建立了反相高效液相色谱法同时测定人血浆中维拉帕米及其主要代谢产物去甲维拉帕米血药浓度.以甲醇—水—三乙胺(67∶33∶0.4,pH6.7)为流动相,乙吗噻嗪(ethmosine)为内标,样品用正己烷—正丁醇混合液提取浓缩后进样,紫外检测器检测(279nm)。此法操作简便,精密度好,日内、日间误差:维拉帕米<8.6%,去甲维拉帕米<7.6%;方法回收率高,维拉帕米、去甲维拉帕米回收率均>92%。两者血药浓度在25～1000ng·ml-1范围内呈线性关系,最小检测浓度维拉帕米:2.5ng·ml^-1,去甲维拉帕米:5.0ng·ml^-1。应用该法测定了6名志愿者口服盐酸维拉帕米片剂后的血药浓度。