Monodispersed and Polydispersed PEG

Monodispersed and Polydispersed PEG

Published by BroadPharm on September 26, 2018

Polyethylene glycol (PEG) is a polyether polymer that is highly stable and water soluble with many applications, from industrial manufacturing to medicine. Figure 1 shows an example of early PEG development.

diagram of antibody drug conjugate linker as well as a description
Figure 1. The initial manufacture of PEG in 1859 used ethylene oxide.

PEG can be classified as Monodispersed PEG and Polydispersed PEG (poly PEG). Monodispersed PEG are pure compounds with precise PEG units and a single molecular weight. In contrast, polydispersed PEG is a polymer mixture with an average molecular weight, such as 5K, 10K, etc.

PEG shapes include linear, branched, star, with a combination of different PEG chain lengths.

PEG can also be anchored with different functionalized groups on the end of the chain for chemistry modification for different research applications. Examples of functional groups include amines, azides, active esters, silanes, tetrazines, and more (Figure 2). Some of the research applications include biotin labeling and fluorescent labeling.

diagram of antibody drug conjugate linker as well as a description
Figure 2. Azido-PEG2-amine and Methyltetrazine-PEG5-triethoxysilane are examples of monodispersed PEG linkers. 4arm-PEG-NH2, MW 10K is an example of branched polydispersed PEG.

With advancements in modern synthetic chemistry and purification technology over the past two decades, monodispersed PEG linkers have become more commercially viable. They have been become very beneficial in drug design and development, specifically in antibody-drug conjugate design and small molecule drugs. Figure 3 shows an example of PEG8 utilized in the ADC drug, Trodelvy. PEG linkers can help to increase a drug's hydrophilicity, fine tune DMPK, and minimize complications due to transport across the blood-brain barrier.

diagram of antibody drug conjugate linker as well as a description
Figure 3. Structure of IMMU-132, an ADC that utilizes a PEG8 linkage to the topoisomerase I inhibitor, SN-38.

Polydispersed PEG, Poly PEG are very useful in the development of PEGylated protein drugs. The poly PEG increases the bulk around the drug and lowers clearance rate. This also lowers the required dosages.

Poly PEG in PEGylated Lipids, such as DSPE-mPEG 2000 or DMG-PEG 2000, have also gained international attention for their use in the COVID-19 vaccines (Figure 4). PEG lipids have been used extensively to improve circulation times for liposome encapsulated (LNP) drugs and reduce non-specific uptakes.

PEG Lipids used in COVID-19 vaccines
Figure 4. PEG Lipids used in COVID-19 vaccines, Pfizer's DSPE-PEG 2000 shown on top and Moderna's DMG-PEG 2000 shown on bottom.

As a worldwide leader of PEG molecules, BroadPharm offers a wide array of PEG Linkers, including monodispersed PEG and polydispersed PEG to empower our customer's advanced research. These compounds feature great aqueous solubility, smart choice of PEG length, and a broad selection of functional groups to choose from.

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