Polyethylene glycols are a family of linear polyethers that are composed of repeating ethylene oxide (CH2-CH2O) units. The number of ethylene oxide units or their approximate molecular weight, such as PEG-4 or PEG-200, usually designates the nomenclature of specific PEGs. PEGs with molecular weight less than 600 are liquid, while PEGs with molecular weight above 1000 are solid. The higher molecular weight PEG is also known as polyoxyethylene or polyethylene oxide (PEO). Different types of PEG structures are available, including linear, branched, comb-link, and star macromolecules. PEGs are easily chemically modified and attachment to other molecules. When attached to other molecules, PEG modulates the solubility and increases the size of the attached molecule. Due to their non-toxicity, hydrotropism, and biocompatibility, PEGs are commonly used in bioconjugation and surface functionalization applications, biomedical research, drug delivery, tissue engineering, and the food and cosmetic industries.
In the preparation and modification of biomaterials, PEG or its derivatives can be used in protein and nucleic acid purification, phase change material, peptide synthesis, phase transfer catalyst, drug conjugation and release, and polymer-bound reagents. PEG coupled with biomolecules, such as lectins, lactose, and biotin, have been used for cellular and intracellular targeting of biomaterials. In drug development applications, PEG has several advantages as it can extend the circulation time of drugs and reduce their immunogenicity. PEG modification increases the molecular weight of protein drugs, reduces renal clearance, and protects them from proteolytic degradation, thereby altering their pharmacokinetic profile. In addition, PEG improves the solubility of the drug due to the water cloud surrounding the polymer. PEG also has advantages with respect to delivery systems of drugs. PEG-functionalized (PEGylation) nanoparticles can bind to the cell membrane and can be used as excellent drug carriers. The stability and internalization of PEGylated nanoparticles may be influenced by factors such as PEG molecular weight, attached functional groups, ligands, and the size of the nanoparticles. PEGylated nanoparticles accumulate in tissues, such as muscle, skin, bone, and liver. High molecular weight PEG remains in the circulation longer than low molecular weight PEG. Small PEGs tend to move freely from the circulation to extravascular tissues. Urinary clearance and hepatic clearance are decreased with increasing molecular weight of PEG. Attachment of the large PEG moiety generally reduces drug activity, and higher conjugate concentrations are required to achieve the desired biological activity.
Amerigo Scientific offers a wide range of well-defined PEGs with various molecular weights, end functionalities, reactivities, and polymer architectures. Our products include multi-arm PEGs, monodispersed PEGs, monofunctional PEGs, heterobifunctional PEGs, bifunctional PEGs, click chemistry PEGs, and other PEG derivatives.
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