Half-Life Extension Service by Polymer Conjugation

For Research Use Only. Not for Clinical Use.

Overview of PEG Polymers

PEG polymers are produced synthetically and can be either linear or branched, and the end group(s) may be either the standard hydroxy group or a methoxy group (denoted mPEG). Up to now, more than 10 PEGylated biopharmaceuticals are approved for various indications, including hepatitis C, acromegaly, leukemia, chronic inflammatory diseases, anemia, and neutropenia, and many more are under development, e.g. for treatment of bleeding disorders.

Different types of PEG structures; mPEG: methoxy-PEG. Fig. 1 Different types of PEG structures; mPEG: methoxy-PEG. (van Witteloostuijn, 2016)

PEGylation in Drug Half-life Extension

PEGylation of biotherapeutics strongly increases its hydrodynamic radius and is achieved by the chemical conjugation of polyethylene glycol chains with a long history of more than 20 years as a half-life extension module. The attachment of PEG moieties to peptides and proteins is a well-established and efficient method for improving their pharmacokinetic properties. PEG polymers are highly hydrophilic and provide with their associated water molecules a hydration shell, which expands the hydrodynamic volume of a polypeptide. This makes the PEGylated molecule less susceptible to renal clearance as well as to protease degradation and can decrease the immunogenicity of native peptides and proteins. PEGylation is considered to be a safe and well-tolerated modification. It confers stealth properties to the therapeutic proteins, avoiding phagocytosis and removal from the bloodstream.

Intratumoral trafficking of drug-loaded, PEGylated nanoparticles (NPs) compared to free drug. Fig. 2 Intratumoral trafficking of drug-loaded, PEGylated nanoparticles (NPs) compared to free drug. (Mozar, 2018)

Other Polymers in Drug Half-life Extension

Recent efforts to improve half-life extension through polymer conjugation include the use of advanced chemistry, including bio-orthogonal labeling, e.g. through the introduction of non-natural coupling groups, and the substitution of PEG by other nondegradable or degradable polymers. Nondegradable polymers include poly(N-vinylpyrrolidone) (PVP), polyglycerol (PG), poly(N-(2-hydroxypropyl) methacrylamide) (PHPMA), and polyoxazolines (POZs). Promising results were, for example, reported for PVP-tumor necrosis factor (TNF), which showed a longer half-life than PEG-TNF, and for G-CSF conjugated with a 20 kDa POZ, with a threefold greater area under the curve (AUC) for neutrophil counts in rats compared to unmodified G-CS. Promising results were also reported for PEG-based and non-PEG-based degradable polymers such as poly[oligo(ethylene glycol) methyl methacrylate] (POEGMA) and poly(2-methyacryloyloxyethyl phosphorylcholine) (PMPC). For example, coupling of PMPC to interferon- α2a resulted in a longer half-life than PEG-interferon-α2a.

Custom Services of Half-Life Extension by Polymer Conjugation

Polymer conjugation is one of the commonly used and effective methods in drug half-life extension research. With years of experience focusing on drug development, Creative Biolabs has established a comprehensive half-life extension platform equipped with strong foundations, advanced technologies, and first-class scientists. We are confident in providing high-quality polymer conjugation-based half-life extension services to global customers:

If you are looking for solutions for half-life extension drug development, or you are interested in any one of our services, please don't hesitate to contact us for more information.


  1. van Witteloostuijn, S. B.; et al. Half-Life Extension of Biopharmaceuticals using Chemical Methods: Alternatives to PEGylation. ChemMedChem. 2016, 11(22): 2474-2495.
  2. Mozar, F. S. and Chowdhury, E. H. Impact of PEGylated Nanoparticles on Tumor Targeted Drug Delivery. Curr Pharm Des. 2018, 24(28): 3283-3296.

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For Research Use Only. Not for Clinical Use.