使用血浆扩张器时的临床药代动力学考虑。
文章的细节
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引用
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克鲁兹U, Kroemer H
使用血浆扩张器时的临床药代动力学考虑。
临床药典,1987年2月;12(2):123-35。
- PubMed ID
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2435442 (PubMed视图]
- 摘要
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本文综述了最常用的血浆膨胀剂右旋糖酐和羟乙基淀粉的药代动力学。这些胶体制剂的复杂成分(在体内和体外分子量分布范围很广)混淆了它们的特异性测定和有意义的药代动力学分析。此外,血浆膨胀器的血浆浓度随时间的下降至少是双相的,在一些临床研究中,血浆浓度监测的时间周期不足以表征最终消除期。右旋糖酐按其平均分子量可分为右旋糖酐1、右旋糖酐40、右旋糖酐60和右旋糖酐70。右旋糖酶对右旋糖的代谢和肾外排泄仅占机体总药物损失的2 - 10%。右旋糖酐在体循环中的滞留和经肾脏途径的清除取决于右旋糖酐的大小及其分子量分布。分子量低于15,000道尔顿的右旋糖酐被不加限制地过滤,因此右旋糖酐1的消除半衰期相对较短(2小时),而右旋糖酐40(10小时)或右旋糖酐60(42小时)的消除半衰期要长得多。在肾功能不全的患者中,消除作用与肾小球滤过率降低同时受损,在这些患者中建议使用小剂量。如果使用多次右旋糖酐输注,也可能需要减少剂量,因为右旋糖酐40在长期使用过程中会大量积累(特别是分子量较高的部分)。由于单次剂量只有约50%至70%的剂量能在48小时内通过尿液恢复,其余剂量可能储存在体内的某个地方。 Disposition of hydroxyethylstarch is dependent on 2 major factors. As with dextrans, the molecular weight distribution affects the rate of renal elimination. In addition, the degree of substitution with hydroxyethyl groups mainly determines the metabolism of hydroxyethylstarch by alpha-amylase, and thus the overall elimination rate. A higher molecular weight range (e.g. hydroxyethylstarch 450,000 vs 200,000) and a more extensive degree of substitution (e.g. 0.7 vs 0.5) result in a slower elimination, as can be seen by comparing the half-life values of hydroxyethylstarch 450/0.7 (48 days) and hydroxyethylstarch 200/0.5 (20 days). Since only 40 to 65% of an infused dose could be recovered in the urine in humans, the remainder of the dose may be stored in the body. Animal experiments suggest that certain fractions of hydroxyethylstarch might be stored in some tissues.(ABSTRACT TRUNCATED AT 400 WORDS)
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