PolyPEG® polymers are synthesised using WEP’s proprietary Living Radical Polymerisation (LRP) technology. LRP builds the polymer in one direction starting with a functional initiator by adding one monomer at a time. This unidirectional synthesis ensures that more structural and compositional control can be achieved than is possible with conventional polymerisation methods that build the polymer from both ends. The functional initiator contains the single active conjugating group for attaching PolyPEG® to the target biological molecules using a range of established or novel chemistries.
The pendant copolymer structure of PolyPEG® polymers not only differentiates PolyPEG® from conventional linear and branched PEGs but also allows a considerable degree of structural diversity to be achieved. The size of the PEG teeth and length of the poly(methacrylate) backbone can be varied so that PolyPEG®s in the size range 10 to 80+ kDa can be synthesised for attachment to biological molecules via the single active conjugating group.
Several different chemistries can be used to covalently attach PolyPEG®s to biological therapeutics. These include a range of established chemistries for site-specific attachment to free cysteine residues, to the amines on lysine residues, or to the terminal amine on biological molecules. Other conjugation chemistries can also be used.