Clin Pharmacokinet
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This review deals with the pharmacokinetics of dextrans and hydroxyethylstarch, the most commonly used plasma expanders. The complex composition of these colloidal agents (broad range of molecular weight distribution in vitro and in vivo) confounds their specific assay and meaningful pharmacokinetic analysis. In addition, the time-dependent decline of plasma concentrations of the plasma expanders is at least biphasic, and in some clinical studies the time period for plasma concentration monitoring has been inadequate to characterise the terminal elimination phase. ⋯ 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)