问题 问答题 简答题

解释前药定义,并举例说明前药原理的意义。

答案

参考答案:

保持药物的基本结构,仅在某些官能团上作一定的化学结构改变的方法,称为化学结构修饰。如果药物经过结构修饰后得到的化合物,在体外没有或者很少有活性,在生物体或人体内通过酶的作用又转化为原来的药物而发挥药效时,则称原来的药物为母体药物,结构修饰后的化合物为前体药物,简称前药(prodrug)。

概括起来,前药的目的主要有(1)增加药物的代谢稳定性;(2)干扰转运特点,使药物定向靶细胞,提高作用选择性;(3)消除药物的副作用或毒性以及不适气味;(4)适应剂型的需要。

完形填空
A little part of me thought about going to another checkout line.This one had the shortest    ,there was only one guy in it,but he was in a     and there seemed to be some difficulties     
We stepped in behind him.At first, he       to be having difficulty getting his groceries onto the counter.But after a while,I realized that what he was actually doing was      it into two parts.
I offered to help,but he and the checkout lady had it under     .He asked Julie if she would mind putting his     basket away.Then he       for his wallet which was in a bag on one side of his chair.The      he was positioned and the fact he only had one usable arm      this troublesome for him,so I helped there.
The checkout operator came around and gave him his     and the goods he needed to have to hand.She      one bag of groceries over a handle at the back of his chair.
I offered to get the other bigger bag and he said,“No.    you could do me a favor.Take that bag along to the entrance and give it to Angela."
Angela,it    ,was collecting food for people who might      go hungry! I hadn’t even     her before.
This guy,in spite of the limitations,had bought more than twice as     shopping as he needed—and given the bigger bag away to help     people!
He didn’t let the fact that he needed help      him from being a help.He may have been limited    ,but his heart was more than able to overcome all that.
小题1:
A.queueB.spaceC.figureD.time
小题2:
A.supermarketB.wheelchairC.helmetD.uniform
小题3:
A.going onB.holding onC.paying offD.setting down
小题4:
A.happenedB.seemedC.usedD.pretended
小题5:
A.selectingB.wrappingC.handingD.separating
小题6:
A.chargeB.controlC.improvementD.settlement
小题7:
A.emptyB.heavyC.largeD.broken
小题8:
A.feltB.searchedC.reachedD.seized
小题9:
A.spotB.directionC.distanceD.way
小题10:
A.caughtB.carriedC.madeD.solved
小题11:
A.basketB.bagC.walletD.change
小题12:
A.arrangedB.hungC.loadedD.connected
小题13:
A.AndB.ButC.SoD.Or
小题14:
A.turned outB.found outC.pointed outD.put out
小题15:
A.alreadyB.alwaysC.otherwiseD.fairly
小题16:
A.noticedB.knownC.understoodD.greeted
小题17:
A.manyB.muchC.fewD.little
小题18:
A.wealthyB.ordinaryC.otherD.normal
小题19:
A.stopB.requireC.leadD.persuade
小题20:
A.financiallyB.morallyC.mentallyD.physically
单项选择题