Patent ID: 8586569

Claim:
A compound of one of the formulae (IIIc-α), (IIIa-β), (IVa-α) or (IVa-β): wherein X is NH, O or S, L is a bond; or L is a linker; or L is a linker, wherein the linker is derived from a diamine; or L is a linker, wherein the linker is derived from an amino acid; or L is a linker, wherein the linker is derived from lysine, glycine or ornithine; or L is a linker, wherein the linker is or forms part of a peptide, an ester or a carbonate; or the PAG-A-L-X— moiety is: wherein Y=bond, O or NH, and m=0 to 30, wherein PAG is a poly(alkylene glycol) and X is NH, O or S; or the PAG-A-L-X— moiety is: wherein Y=bond, O or NH, and m=0 to 30, wherein PAG is a poly(alkylene glycol) and X is NH, O or S; or the PAG-A-L-X— moiety is: wherein Y=bond, O or NH, m=0 to 30, and n=0 to 30, wherein PAG is a poly(alkylene glycol) and X is NH, O or S; or the PAG-A-L-X— moiety is: wherein Y=bond, O or NH, Z═O or NH, m=0 to 30, and n=0 to 30, wherein PAG is a poly(alkylene glycol) and X is NH, O or S; or the PAG-A-L-X— moiety is: where Y=bond, O or NH, and m=0 to 30, wherein PAG is a poly(alkylene glycol) and X is NH, O or S; or the PAG-A-L-X— moiety is: wherein Y=bond, O or NH, m=0 to 30, and n=0 to 30, wherein PAG is a poly(alkylene glycol) and X is NH, O or S; or the PAG-A-L-X— moiety is: wherein m=1 to 6, wherein PAG is a poly(alkylene glycol) and X is NH, O or S; or the PAG-A-L-X— moiety is: wherein m=1 to 4, wherein PAG is a poly(alkylene glycol) and X is NH, O or S; or the PAG-A-L-X— moiety is: wherein m=1 to 6, wherein PAG is a poly(alkylene glycol) and X is NH, O or S; or the PAG-A-L-X— moiety is: wherein m=1 to 4, wherein PAG is a poly(alkylene glycol) and X is NH, O or S; or the PAG-A-L-X— moiety is: wherein m=1 or 2, wherein PAG is a poly(alkylene glycol) and X is NH, O or S; or the PAG-A-L-X— moiety is: wherein m=1 or 2, wherein PAG is a poly(alkylene glycol) and X is NH, O or S; or the PAG-A-L-X— moiety is: wherein PAG is a poly(alkylene glycol) and X is NH, O or S; or A is —O—CO—; or the poly(alkylene glycol) is poly(ethylene glycol); or the poly(ethylene glycol) is monomethoxy poly(ethylene glycol).