What is polyethylene glycol (PEG) modification?

Polyethylene glycol (PEG) modification is a polyethylene glycol with functional groups, which is mainly used for protein drug modification to increase in vivo half-life, reduce immunogenicity, and at the same time increase the water solubility of drugs.

Polyethylene glycol (PEG) modification is widely used in pharmaceutical research and development, and plays an important role in the sustained release of drugs.

In recent years, biological macromolecular drugs such as protein peptides and natural product drug molecules have been increasingly used in the field of disease treatment, which has greatly promoted the development of the pharmaceutical industry. However, the role of biological macromolecules in the medicinal process is greatly limited due to their short half-life, easy to produce immunogenic antigenicity, easy enzymatic hydrolysis, and certain pharmacological toxicity. In order to effectively solve this problem, the purpose of prolonging the drug effect is achieved by chemically modifying the drug molecule with polyethylene glycol. Because of the steric hindrance of the polyethylene glycol chain, the resistance of the modified protein to protease hydrolysis is greatly improved, and the molecular exclusion volume of the modified molecule is significantly increased, so that the renal filtration clearance rate is significantly reduced. At the same time, the structural specificity of the polyethylene glycol molecule reduces the ability of the liver reticuloendothelial system to recognize, uptake and clear the modified protein, and can reduce or eliminate the ability to induce neutralizing antibodies and bind to antibodies, making it It is difficult to be recognized and cleared by the immune system. These effects make the polyethylene glycol-modified drug molecules have better pharmacological and pharmacokinetic properties than unmodified drugs.

Of all the polymers applied to molecule altering structural chemistry, polyethylene glycol (PEG) modification has numerous benefits and relatively few drawbacks. PEG is now increasingly being applied to the problems of tumour targeting, both in the context of the passive targeting of PEG-liposomes and in active targeting strategies using PEGylated anti-tumour antibodies. PEG can also serve as a useful linker molecule between targeting moieties and other agents, including cytotoxic or imaging agents and targeted liposomes. Despite these demonstrated benefits and the level of attention which PEGylation has received, relatively little consideration has been given to two key areas: first, the extent to which the coupling method has an impact on both the functionality of the PEG-adduct and the acquisition of beneficial properties; second, that the impact of PEGylation on biodistribution is complex, thus any attempt to optimise a PEG-peptide or PEG-liposome for a particular task must involve an examination of all the individual facets of the effects of PEGylation. Studies investigating the underlying principles of tumour targeting suggest that current views concerning the optimisation of PEGylated vehicles for tumour localisation need to be re-examined.


Polyethylene glycol (PEG) is a safe, inactive, and nontoxic polymer that is commonly used for molecular modification. Therapeutic benefits of protein modification with polyethylene glycol include reduced renal and cellular clearance and increased half-life; enhanced protection against proteolysis; and reduced toxicity. The purpose of PEGylation of biologically active proteins is to improve their pharmacokinetic and pharmacodynamic properties while retaining the intrinsic biological activity of the native protein. In order to improve the pharmacological activity and clinical efficacy, the pharmacokinetics and pharmacodynamics of polyethylene glycol proteins need to be optimized, and the structure, length, molecular weight and modification methods of the PEG polymer chain are all factors that affect the optimization.

Common modifying groups:

Amino (-Amine)-NH2, Aminomethyl-CH2-NH2, Maleimide-Mal, Carboxyl-COOH, Sulfhydryl (-Thiol)-SH, Propionaldehyde-ALD, Succinimidyl Carbonate-SC, Succinimidyl Acetate-SCM, Succinimidyl Propionate-SPA, Succinimidyl Succinate-SS, Succinimidyl-NHS, Dithiopyridyl-OPSS, Propionyl-CH2CH2COOH, Aldehyde-CHO, N-pyridinedithio-S-S-Pyridine, Mercapto-VS, Acrylate-Acrylate, Acrylic-AC, Azide-Azide, Biotin-Biotin, Epoxy-EP, Fluorescence Fluorescein-Fluorescein, Glutaryl-GA, Hydrazide-Hydrazide, Alkynyl-Alkyne, p-Nitrophenylcarbonate-NPC, Isocyanato-NCO, Ortho-dithiopyridyl-OPSS, Silyl -Silane, -SVA, BOC-, Carboxymethyl-CM, Fmoc-NH-.

AxisPharm has over 5,000 high purity PEG reagents kept in stock. The wide selection of lengths and functionalities will empower the PEGylation, bioconjugation, crosslinking, ADC drug development, and biolabeling for pharmaceutical and biotech R&D.
AxisPharm offers a range of PEG based reagents with different linker lengths, bearing various reactive groups. such as mPEG, PEG Acid, PEG Amine, PEG Azide, Maleimide PEG, NHS ester PEG, Bromide PEG and others.You can learn more by the following categories.

AxisPharm develops a broad range of Linkers and provide custom linker synthesis. Our current product catalog covers click chemistry tools such as DBCO linker, Tetrazine, TCO, BCN linker and Cycloprpene etc., biotin linkers, PEG linkers, peptide linkers, glucuronide linkers, photo cleavable linkers, Fluorescent Dye probe linkers (you may need fluorophores list) and folic acid peg linkers.

As a customer-oriented contract research company, we offer flexible ADC Linker product kits and Bioconjugation services with competitive price.