Noncovalent PEGylation of protein and peptide therapeutics

Abstract

Clinical applications of protein therapeutics—an advanced generation of drugs characterized by high biological specificity—are rapidly expanding. However, their development is often impeded by unfavorable pharmacokinetic profiles and largely relies on the use of drug delivery systems to prolong their in vivo half‐life and suppress undesirable immunogenicity. Although a commercially established PEGylation technology based on protein conjugation with poly(ethylene glycol) (PEG)—protective steric shield resolves some of the challenges, the search for alternatives continues. Noncovalent PEGylation, which mainly relies on multivalent (cooperative) interactions and high affinity (host–guest) complexes formed between protein and PEG offers a number of potential advantages. Among them are dynamic or reversible protection of the protein with minimal loss of biological activity, drastically lower manufacturing costs, “mix‐and‐match” formulations approaches, and expanded scope of PEGylation targets. While a great number of innovative chemical approaches have been proposed in recent years, the ability to effectively control the stability of noncovalently assembled protein–PEG complexes under physiological conditions presents a serious challenge for the commercial development of the technology. In an attempt to identify critical factors affecting pharmacological behavior of noncovalently linked complexes, this Review follows a hierarchical analysis of various experimental techniques and resulting supramolecular architectures. The importance of in vivo administration routes, degradation patterns of PEGylating agents, and a multitude of potential exchange reactions with constituents of physiological compartments are highlighted.This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease

Polyethylene Glycol-Mediated Exosome Isolation: A Method for Exosomal RNA Analysis

“…Besides, this method showed a higher RNA yield owing to the greater amount of the exosomes obtained. The miRNAs within exosomes are of crucial importance as they potentially represent candidate biomarkers owing to their inherent stability [ 20 ] , and thus, the PEG-mediated strategy could provide researchers with easy access to RNA content of the exosomes.…”

Non-covalent PEGylation of proteins mediated by site-specific in situ polymerization induced co-assembly

“…12 In response to these limitations, several studies have sought to develop non-covalent PEGylation strategies aiming to enhance conjugation efficiency, streamline downstream purification processes, and circumvent any adverse effects on protein structure and activity induced by covalent chemical reactions. 13,14 Examples include various non-covalent PEGylation strategies based on host-guest interactions, 15 histidine-metal ion coordination interactions, 16 hydrophobic interactions, 17 and ionic interactions. 18 However, these methods still require intricate designs and optimizations tailored to proteins with different properties (e.g., differences in hydrophobic domain density, surface charge, and specific amino acid content), or even require protein engineering to achieve, thus resulting in poor generality.…”