Both polyethylene glycol (PEG) and monomethoxy polyethylene glycol (MPEG) have been used for many years as non toxic auxiliary materials in cosmetics, foodstuffs and pharmaceuticals and are approved by the FDA.
The conjugation of PEGs or MPEGs to therapeutic proteins improves their in vivo circulating half-life and the solubility of proteins in aqueous solution.
The PEG chain modulates the pharmacokinetic and -dynamic profile in a way that the amount of administered active pharmaceutical ingredient can be reduced without compromising the drug’s efficacy.
PEGylated therapeutic proteins have a reduced toxicity and are almost non immunogenic. As a result, therapeutic side effects are significantly reduced as compared to the unmodified protein.
Size comparison of PEG with other molecules
When attached to an API, polyethylene glycole (PEG) allows for a decelerated clearance of the drug. This induces longer-acting medicinal effects, reduces toxicity and allows for longer dosing intervals. Examples include PEG-interferon alpha (hepatitis C) and PEGfilgrastim (neutropenia).