Determination of the Enantiomers of (±) -Trans Tramadol and (±)-Trans O-demethyltramadol in Human Serum and Its Application in Therapeutic Drug Monitoring
LIU Hui-CHen,YANG Yan-Yan,WANG Ya-Li,HU Yu-Qin,HOU Yan-Ning
(Bethune International Peace Hospital, Shijiazhuang 050082)
Abstract OBJECTIVE: To establish a method for determining the enantiomers of (±)-trans tramadol ((±)-trans T) and (±)-trans O-demethyltramadol ((±)-M1) in human serum, and to study the relationship between the clinical actions and the serum concentrations of the enantiomers of (±)-trans T and (±)-M1. METHODS: By using sulfobutylether-b-cyclodextrin as a chiral selector, a high performance capillary electrophoresis (HPCE) method was developed to analyze the enantiomers of (±)-trans T and (±)-M1. Twenty postoperative patients were divided into two groups and given multiple intravenous doses of (±)-trans T hydrochloride, 400 mg·d-1 or 300 mg·d-1. The relationship between the clinical actions and the serum concentrations of the enantiomers of (±)-trans T and (±)-M1was studied. RESULTS: The enantiomers of (±)-trans T and (±)-M1 in human serum were separated well. The linear ranges were 20~640 mg·L-1 for the enantiomers of (±)-trans T, 10~160 mg·L-1 for the enantiomers of (±)- M1. For the enantiomers of (±)-trans T and (±)-M1, the within-day and day-to-day RSDs were less than 10% and 15% respectively; the relative recoveries were from 92.30% to107.80%; the limit of detection was 1.10mg·L-1. The concentrations of the enantiomers of (±)-trans T, the frequency and serious level of adverse reactions were higher in 400 mg·d-1 group than that in 300 mg·d-1 group. The concentrations of the enantiomers of (±)- M1, and the analgesic effect were similar between the two groups. Conclusion: The HPCE method could be used in clinical therapeutic drug monitoring. There was close relationship between the analgesic effect and the concentration of (+)-M1 in serum. The frequency and serious level of adverse reactions might be attributed to the higher concentrations of the enantiomers of (±)-trans T, which may be due to the saturated metabolism.
Key words (±)-trans tramadol; (±)-trans O-demethyltramadal; enantiomer
反式曲马朵(trans tramadol,(±)-trans T)为新型中枢镇痛药,临床上用于中度、中重度疼痛的治疗,不易引起呼吸抑制、成瘾和滥用。T分子中含两个手性碳原子,有四个立体异构体,其中(+)-(1R,2R)-T((+)-trans T)和(-)-(1S,2S)-T ((-)-trans T)为药用品。(+)-trans T和(-)-trans T的作用机理是抑制单胺递质的再摄取和促进单胺递质的释放,(+)-trans T的代谢物(+)-(1R,2R)-氧去甲基曲马多((+)-trans O-demethyltramadol, (+)-M1)则是通过激动μ-阿片受体而发挥作用[1,2]。为了评价和优化临床盐酸(±)-trans T的给药方案,本文在前文[3]基础上建立了同时测定人血清中(±)- trans T和(±)-M1对映体浓度的高效毛细管电泳(high performance capillary electrophoresis, HPCE)法,并研究了术后病人血清中 (±)-trans T和(±)-M1对映体浓度与临床效果的关系。
材 料 与 方 法
1.仪器与试剂
P/ACE 5000 HPCE, 配紫外检测器及Gold色谱软件; 未涂层石英毛细管(75mm,i.d.), 总长37 cm, 有效长度30 cm, 美国Beckman公司产品。盐酸(±)-trans T(批号5D7416)、 盐酸(+)-trans T(批号06)、 盐酸(-)-trans T(批号07)、(±)-M1(批号TK168), 德国Grünenthal Gmbh公司惠赠;盐酸(±)-cis T,锦州医学院化学教研室合成。磺丁基-β-环糊精,中国科学院兰州化物所合成;Tris,H3PO4,NaOH,HCl 均为市售分析纯;超纯水。
2.病例与分组
20例接受心胸外科肿瘤切除术后入住ICU病房的病人,受试前需征得受试者知情同意,随机分为两组。400 mg ·d-1组:10例,男6例, 女4例;年龄(59±7)岁,体重(60±10)kg;贲门癌7例,食管癌2例,肺癌1例。300 mg·d-1组:10例,男8例,女2例;年龄(64±12)岁,体重(64±8)kg;贲门癌7例,食管癌2例,肺癌1例。两组病人术前、术中、术后的其它用药尽可能保持一致。
3.药品与给药方法
盐酸(±)-trans T注射液,每支100 mg,德国Grünenthal Gmbh公司生产,批号9706。病人术后到ICU病房完全清醒后即开始给予盐酸(±)-trans T注射液,加于50mL生理盐水中恒速静滴,日剂量平均分为3次,每次6 h,间隔2 h。连续给药5次后,即第1次给药后38h取血3 mL,离心分离血清,冻存备用。
4.样品处理与测定
1 ml血清中加 1mg·L-1 盐酸cis T溶液100μl,0.5 mol·L-1 NaOH 0.5 ml,乙酸乙酯5 ml,充分混匀2 min,离心(5000 r·min-1)15 min,取上清液4 ml以氮气流吹干,残渣用100μl水溶解,取30μl上机分析。分析条件:磺丁基-β-环糊精以40 mmol·L-1 Tris缓冲液(H3PO4 调pH至2.5)溶解配制分离介质,磺丁基-β-环糊精的浓度0.8 mmol·L-1;进样电压10 kV,20 s,入口为阳极;分离电压15 kV,柱温25 ℃,检测波长214 nm。
5.临床效果评价
目测划线法(visual analgesic scale, VAS)记录用药后疼痛的程度,设0为无痛,10为重度疼痛。治疗开始后密切观察并记录出现的药物不良反应及其程度,并根据药物不良反应的判断标准判定不良反应与药物的关系。
6. 统计学处理
两组病人疼痛评分采用t-检验,药物不良反应发生率采用c2-检验。
结 果
1 血药浓度测定方法[3]
1.1 分离效果
T的四种立体异构体及(±)-M1对映体达到基线分离,且血清组分无干扰峰。(±)-cis T对映体的tR分别为8.16 min和8.73 mim ,(+)-trans T和(-)-trans T的tR分别为9.46 min和10.52 mim;(+)-M1和(-)-M1的tR分别为7.98 min和8.43 mim。典型电泳图谱见图1。
1.2 标准曲线
以(±)-cis T后出峰的对映体为内标,血清中(+)-trans T,(-)-trans T浓度在20~640 mg·L-1范围内,(+)-M1和(-)-M1浓度在10~60 mg·L-1范围内,其峰面积和内标峰面积的比值(Y)与浓度(X)呈良好的线性关系,回归方程分别为
(+)-trans T:Y=-0.1587+0.01827X(n=6, r=0.9957);(-)-trans T:Y=-0.5037+0.01865X(n=6, r=0.9924);(+)-M1:Y=-0.3020+0.02000X(n=5, r=0.9949);(-)-M1:Y=0.1073+0.01987X(n=5, r=0.9980)。
Fig1. Electropherogram of a serum sample spicked with ( )-cis
tramadol. 1. an unknown metabolite; 2. (+)-trans O-demethyltramadol; 3.
one enantiomer of ( )-cis tramadol; 4. (-)-trans O-demethyltramadol;
<