The pharmacokinetic studies of diltiazem and its major active metabolites in human by HPLC
Tan Hengshan,Yang Je,Cai Minghong,et al
(General Hospital of Nanjing Armed Forces,Nanjing 210002)
A HPLC method for simultaneous determination of diltiazem(DZ) and its major metabolite desacetyldiltiazem (M1) in human plasma was described using SPHERISORB ODS 5μm analytical column for separation.An aliquot of the aqueous acid phase was chromatographed using methanol-acetonitrite-water (60∶10∶30) containing 0.08% acetic acid and 0.04% triethylamine as mobile phase.The wavelength used for detection was 237nm.The propafenon was used as the internal standard.The detection ranges were 5.45~272.5ng·ml-1 for DZ and 5.85~292.5ng·ml-1 for M1.The methods are highly sensitive with limits of detection at 2.87ng·ml-1 for DZ and 1.99ng·ml-1 for M1 respectively.The recoveries were about 101.88% for DZ and 101.72% for M1 respectively.The RSD values of within-day and between-day were all lower than 12%.After 4 healthy volunteers received 90mg diltiazem tablets,the time curves of concentration in plasma were fitted by PKBP-N1 program.DZ was fitted to a one compartment open model.M1 was fitted to a two compartment open model.The results showed that T1/2 of DZ and M1 were 5.63±1.48h and 14.49±7.08h respectively.
Key wordsdiltiazem,pharmacokinetics,HPLC
盐酸地尔硫是一种新的钙通道阻断剂,是治疗心绞痛、高血压等心血管疾病的首选药物之一。有关地尔硫的血药浓度测定方法,国内已有报道[1-3],但对其主要代谢产物-去乙酰地尔硫的药物动力学研究未见报道。本文建立了一种HPLC法同时测定人血清中盐酸地尔硫(DZ)和去乙酰地尔硫(M1)浓度的方法,并进行了DZ和M1的药物动力学研究,结果报道如下。
1实验方法
1.1仪器和试药LC-6A高效液相色谱仪(日本株式会社岛津制作所),FCV-2AH高压流路切换阀,SPD-6AV紫外检测器,SCL-6B控制器,CR-6A数据处理机。盐酸地尔硫对照品(杭州民生药厂提供),去乙酰地尔硫对照品(上海淮海制药厂提供)。合心爽(盐酸地尔硫)片剂30mg dZ/片(日本田边制药株式会社,批号44034)。盐酸普罗帕酮注射液3.5mg·ml-1(上海信谊药厂,批号920802)。甲醇、乙腈、正己烷、异戊醇、冰醋酸和三乙胺均为分析纯试剂。
1.2色谱条件和血样处理[4-6]
1.2.1色谱条件采用日本岛津LC-6A高效液相色谱仪,色谱柱:Spherisorb ODS,5μm,4.6×250mm(大连化物所提供);流动相:甲醇∶乙腈∶水(60∶10∶30),内含0.08%冰醋酸,0.04%三乙胺,使用前过滤,超声脱泡。检测波长237nm,流量1.0ml·min-1,检测灵敏度0.001,纸速1mm·min-1,进样体积20μl。
1.2.2血样预处理取1.0ml血清,加内标10μl(盐酸普罗帕酮28μg·ml-1),再加正己烷∶异戊醇(98∶2)混合溶剂每次4ml,提取两次。每次振荡3min,离心(3000r·min-1)5min,合并有机层。取7ml提取液,加0.01mol·L-1盐酸100μl,充分振摇30次,离心(3000r·min-1)5min,弃去有机层,水层取20μl进样。
1.2.3DZ和M1的血清标准曲线配制于空白血清1.0ml中加入内标10μl,再加入DZ和M1标准液,使其浓度分别为:DZ 5.45,10.9,27.25,54.5,109.0,163.5,272.5ng·ml-1;M1 5.85,11.7,29.25,58.5,117.0,175.5,292.5ng·ml-1。按血清预处理方法处理后进样。分别以DZ和M1的浓度对色谱峰高比Y(HDZ/H内)和Y'(HM1/H内)进行回归计算,得到血清标准曲线方程。
1.2.4回收率取4种不同浓度(DZ:10.9,54.5,109.0,163.5ng·ml-1;M1:11.7,58.5,117.0,175.5ng·ml-1)的血清样品,按血清预处理操作,每个浓度做8次,用实测值与理论值之比计算回收率。
1.2.5精密度试验用4种不同浓度的DZ和M1血样,按血样预处理测定峰高比,每种浓度连续进样5次,得日内差;4种浓度在2周内测定7次,得日间差。
1.2.6干扰实验因临床上往往合并用药,所以我们预试了30多种有关的心血管药物干扰试验,考察本法的专属性。
1.3人体试验
1.3.1受试者4名年轻健康男性,具有标准体重,血尿常规和肝肾功能以及心电图均属正常。2周前未用其它药品,服药前空腹12h以上,服药后4h进统一餐,试验期间可饮水,禁酒、茶和吸烟。
1.3.2血样采集口服合心爽90mg,分别于0.5,1,1.5,2,3,4,5,6,8,10,12,24h静脉采血3ml,离心,取血清1ml,按血样预处理操作,测得DZ和M1的峰高。
1.3.3数据处理4名受试者的药时曲线用PKBP-N1程序在386微机上进行拟合,得到DZ和M1的药物动力学参数。
2结果
2.1色谱行为和标准曲线用不同浓度的DZ和M1对峰高比进行线性回归,得血清标准曲线方程分别为:
DZ:Y=0.02194C-0.01303,r=0.9996(5.45~272.5ng·ml-1)
M1:Y=0.02492C-0.00753,r=0.9998(5.85~292.5ng·ml-1)
DZ的最低检测浓度为2.87ng·ml-1,M1的最低检测浓度为1.99ng·ml-1。层析结果为单一色谱峰,出峰保留时间为:DZ 10.3min,M1 8.4min和内标(盐酸普罗帕酮)12.9min。色谱图见图1。
图 1色谱图
A 标准品中地尔硫及去乙酰地尔硫色谱图;B 空白血清中内标的色谱图;C 样品血清中地尔硫去乙酰地尔硫及内标色谱图;1 地尔硫;2 去乙酰地尔硫;3 内标(盐酸普罗帕酮)
2.2回收率用4种不同的DZ和M1血清标准品进行回收试验,其结果见表1。
表 1地尔硫
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