Patent ID: 8067637

Claim:
Compounds of formula (I) wherein each R 1 are the same or different and denote the moieties CH 2 —O—CH 2 —R 3 ; R 2 denote R 1 or one of the moieties C 1 -C 4 alkyl, CH 2 O(C 1 -C 4 alkyl) and OH, where the alkyl group may carry one or more hydroxy groups; each R 3 are the same or different and denote a C 1 -C 4 alkylene moiety having α-hydroxy and ω-NR 4 R substituents and where the alkylene group may be further hydroxylated; each R 4 are the same or different and denotes a hydrogen atom or an acyl moiety; and each R independently are the same or different and denote a triiodinated phenyl group where at least one of the R groups is further substituted by a hydrophilic group; and salts or optical active isomers thereof.