药学英语药学英语 (13).ppt

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1、 Unit SixBiopharmaceutics 生物药剂学生物药剂学 Part onev生物药剂学生物药剂学是研究给药后药物从吸收到消除的整个体内过程，以及各种制剂因素和生物因素对这一过程和药效的影响。v1950年代初，人们普遍认为“化学结构决定药效”，药剂学只是为改善外观、掩盖不良嗅味而便于服用。随着大量的临床实践证明，人们逐渐开始认识到剂型和生物因素对药效的影响。v因此研究药物在代谢过程的各种机理和理论及各种剂型和生物因素对药效的影响，对控制药物制剂的内在质量，确保最终药品的安全有效，提供新药开发和临床用药的严格评价，都具有重要的意义。BioavailabilityvThe thera

2、peutic response of a drug depends on the concentration of the drug being achieved and maintained at the target site.vFor systemically 全身 acting drugs,i.e.drugs that reach target sites via systemic circulation 体循环,a dynamic equilibrium exists between the concentration of drug at its site(s)or action

3、and the concentration of drug in the blood plasma 血浆.v药物的治疗效果取决于靶部位药物的初浓度和维持浓度。v作用于全身的药物，即药物通过体循环到达靶点，在其作用位点浓度和血浆浓度间存在动态平衡。vAs a result,the therapeutic concentration of a drug at its site(s)of action can be adjusted by its plasma concentration.vThe unbound drug concentration in plasma represents a m

4、ore accurate therapeutic index than the drug concentration in whole plasma since a drug may often reversibly bind to plasma proteins.v因此，药物在其作用位点的治疗浓度可通过血药浓度来调节。v由于药物可能与血浆蛋白发生可逆性结合，血浆中的游离药物浓度比全血药物浓度更能准确的表示治疗指数。vOnly drugs that are unbound can permeate through the vascular endothelium 内 皮 and distrib

5、ute to tissues and hence its site(s)of action.vDrug concentrations in whole blood may not be an appropriate therapeutic index because drugs can bind to or enter blood cells.v只有游离型药物可以透过血管内皮层并分布到各组织，进而到达其作用位点。v由于药物可以与血浆蛋白结合或进入血细胞以药物储库形式存在，故全血药物浓度不是一个恰当的治疗指数。vHowever,to determine the concentration of

6、an unbound drug in plasma requires complex and sensitive analytical methods to differentiate unbound drugs from bound drugs.v然而，为确定血浆中游离药物的浓度，需要使用复杂、灵敏的分析方法以区分游离药物与结合药物。vBased upon the assumption that the plasma drug concentration is directly proportional to the therapeutic effect of the drug,plasma

7、 drug concentration is thus regarded as an index to evaluate drug concentration at the site(s)of action and the therapeutic effects of the drug.v基于血浆药物浓度与药物治疗效果成正比这一假设，血浆药物浓度被认为是评价药物在作用部位浓度和药物疗效的一个指数。vHowever,one should not draw inferences 推 论about the therapeutic effects of a drug simply from its plasma concentration until it has been established that the two are consistently correlated.v然而，仅在确定药物血浆浓度和药物疗效相关时，我们才能根据药物血浆浓度推测药物的治疗效果。