PEG Derivatives

Both Polyethylene glycol (PEG) and Monomethoxypolyethyleneglycol (mPEG) have been used for many years as non toxic auxiliary materials in cosmetics, foodstuffs and pharmaceuticals (FDA accepted).The conjugation of PEGs or mPEGs with therapeutic proteins improves their in vivo circulating half-life and the aqueous solubility of the protein.

The PEG chain modulates the pharmaceutical characteristics (pharmacokinetic and pharma-codynamic) in a way that the amount of administered active pharmaceutical ingredient can be reduced while the bio-activity does not decrease.PEGylated therapeutic proteins show a reduced toxicity, are almost non immunogenic and as a result, demonstrate less adverse effects compared with the free proteins.

Linkers & Activators

PEGylation of lipids, liposomes or biomolecules often affords the activation of a functional group, e.g. the presentation of thiol groups for the reaction with MalPEG.Sometimes this is done by the cleavage of disulfide bonds, sometimes by the conversion of amino to thiol groups (see 2-Iminothiolane).

Special spacers are needed for controlled cleavage under physiological conditions or just for sterical reasons.