The present invention relates to a method of producing a hydroxyalkyl starch derivative, said hydroxyalkyl starch having a structure according to formula (I)comprising reacting- hydroxyalkyl starch of formula (I) at its optionally oxidized reducing end or- a hydroxyalkyl starch derivative, obtainable by reacting hydroxyalkyl starch of formula (I) at its optionally oxidized reducing end with a compound (D), said compound (D) comprising-- at least one functional group Z1 capable of being reacted with the optionally oxidized reducing end of the hydroxyalkyl starch, and-- at least one functional group W,with a compound (L) comprising- at least one functional group Z1 capable of being reacted with said hydroxyalkyl starch, or at least one functional group Z2 capable of being reacted with functional group W comprised in said hydroxyalkyl starch derivative, and- at least one functional group X capable of being reacted with a functional group Y of a further compound (M),wherein said functional group Y is selected from the group consisting of an aldehyd group, a keto group, a hemiacetal group, an acetal group, and a thio group. The present invention further relates to the hydroxyalkyl starch derivatives as such ans a pharmaceutical composition comprising the hydroxyalkyl starch derivatives.
