基于多级质谱裂解规律结合SD大鼠在体肠襻给药模型研究西地那非经肠吸收与代谢特性  

Intestinal absorption and metabolic characteristics of sildenafil:a study using in situintestinal administration rat model based on mass fragmentation pathway

作　　者：礼嵩[1,2,3] 倪海涛[4] 盛夏[1] 唐守艳[1] 陆雯静 程春燕[1] 李伟[3] 范国荣[2] 孙颖浩[1] 

机构地区：[1]第二军医大学长海医院泌尿外科GCP平台,上海200433 [2]第二军医大学药学院药物分析学教研室,上海市药物(中药)代谢产物研究重点实验室,上海200433 [3]沈阳药科大学药学院药物分析学教研室,沈阳110016 [4]第二军医大学基础部组织学与胚胎学教研室,上海200433

出　　处：《第二军医大学学报》2014年第1期61-67,共7页Academic Journal of Second Military Medical University

基　　金：国家"重大新药创新"科技专项(2012ZX09303-011-002;2009ZX09301-011-07)~~

摘　　要：目的探讨西地那非及其活性代谢产物N-去甲西地那非的液相色谱-电喷雾多级质谱[LC-ESI(+)MSn]裂解规律,考察西地那非经肠吸收与代谢特征。方法采用ESI质谱分析技术,在正离子检测模式下,分别对西地那非、N-去甲西地那非进行LC-ESI(+)MSn裂解分析,解析其中的主要碎片离子以及可能的裂解途径。基于裂解规律建立西地那非、N-去甲西地那非的LC-ESI(+)MS/MS的SD大鼠血浆样品分析方法,取25只成年健康雄性SD大鼠,随机分成5组,每组5只,以在体肠襻给药模型法给予硫酸氢钠西地那非原料药10mg/kg,于给药前及给药后0.25、0.5、1、4h时在肝门静脉处取血测定,每个时间点一组SD大鼠,考察药物经肠道吸收及在肠系膜处代谢情况。结果质谱裂解规律表明,西地那非及N-去甲西地那非均获得丰度较高的m/z311、283特征碎片质谱峰,证明药物在C-S键处不稳定易发生断裂脱去C5H12O2N2S,在乙氧基C-O键处不稳定易发生断裂脱去C2H4,最终形成稳定m/z283碎片离子。以m/z475→m/z283(西地那非)和m/z461→m/z283(N-去甲西地那非)为离子反应监测通道对在体肠襻给药模型进行半定量分析,结果表明除以原型药物西地那非的形式吸收外,在体肠中约有1/5原型药物经肠代谢生成活性代谢产物N-去甲西地那非,并与原型药物同时吸收。结论西地那非和N-去甲西地那非经质谱裂解均形成稳定的m/z283二级碎片离子;西地那非在体肠吸收时伴随氮去甲基代谢反应同时发生,约有1/5的原型药物代谢生成活性代谢产物N-去甲西地那非。Objective To investigate the fragmentation pathways of sildenafil and its active metabolite N- desmethylsildenafil, so as to understand the intestinal absorption and metabolic characteristics of sildenafil. Methods Using electrospray ion technology （positive ion mode）, we analyzed the fragmentation pathways of sildenafil and its active rnetaboliteN-desmethylsildenafil. Based on the rule of cracking, a LC ESI（＋）MS/MS method was developed to determine the intestinal absorption of sildenafil and metabolism of active metabolites N desmethylsildenafil in the mesenterium. Totally 25 healthy adult male SD rats were randomly divided into five groups and each group contained 5 rats. The hepatic portal venous blood samples were obtained from rats after intestinal administration of 10 mg/kg of sildenafil citrate. The absorption and metabolism were examined in the in situ intestinal administration model at premedication, 0. 25 h, 0. 5 h, 1 h and 4 h （five groups） after medication. Results Mass spectrometric pyrolysis of sildenafil and its active metabolite N-demethylsildenafil showed ion peaks m/z 311 and 283, indicating that the C-S bond was unstable and was liable to lose C5 H12 02 N2 S, and the C-O bond was unstable and was liable to lose C2 H4 , finally forming stable fragment ions. When m/z 475→m/z 283 （sildenafil） and m/z 461→m/z 283 （N-demethylsildenafil） were used as ion reaction channel, sildenafil were absorbed not only in the form of sildenafil in the intestine, but also in the form of its active metabolite N-demethylsildenafil metabolisming as 1/5 of the prototype drugs were finally changed into N-demethylsildenafil. Conclusion Both sildenafil and N-demethylsildenafil can be cracked into stable m/z 283 secondary ions. Intestinal absorption is accompanied by its nitrogen demethylation reaction, which leads to the fact that about 1/5 of prototype drug metabolized into active metabolite N-demethylsildenafil.

关 键 词：西地那非 N-去甲西地那非 在体肠襻给药模型 质谱裂解 

分 类 号：R979.9[医药卫生—药品]