Hydroxyethyl Starch - Pharmacokinetics

Pharmacokinetics

Different types of hydroxyethyl starches are typically described by their average molecular weight, typically around 130 to 200 kDa (bearing in mind that there will be a range of different-sized molecules in any given solution); and their degree of molar substitution (what proportion of the glucose units on the starch molecule have been replaced by hydroxyethyl units), typically around 0.35 to 0.5. A solution of hydroxyethyl starch may further be described by its concentration in % (i.e. grams per 100ml). So for example, one commercially available hydroxyethyl starch (Voluven) is described as 6% HES 130 / 0.4.

The elimination depends on molar substitution degree. Molecules smaller than the renal threshold (60–70 kDa) are readily excreted in the urine while the larger ones are metabolized by plasma α–amylase before the degradation products are renally excreted.