What is "pentastarch"

Pentastarch is a subgroup of hydroxyethyl starch, with five hydroxyethyl groups out of each 11 hydroxyls, giving it approximately 50% hydroxyethylation. This compares with tetrastarch at 40% and hetastarch at 70% hydroxyethylation, respectively.

It is sold under the name Pentaspan and used for fluid resuscitation. It is considered a plasma expander because it remains primarily intravascular after infusion.