Pegylated Drug Delivery Systems: From Design to Biomedical Applications

Abstract

Pegylation, as a simple procedure to attach hydrophilic polyethylene glycol (PEG) onto therapeutic molecule or drug carriers has been utilized widely to deliver small molecules, proteins and peptides. It was first reported in 1970s by Dr. Frank Davis of Rutgers University and Dr. Abuchowsky in the studies of PEG modified albumin and catalase. The significance of this method at that time was able to successfully modify the enzyme with better hydrophilicity but also keep the enzymatic activity. The employment of PEG has provided superior stability of drug delivery systems (DDS) and enhanced the circulation time in vivo. Simple conjugation of PEG chains with various molecular weights enables the possibility to regulate the properties of desired DDS and led to important contribution in targeting therapy and diagnosis. Pegylation has been reported to be able to protect peptides by shielding antigenic epitopes from reticuloendothelial (RES) clearance and avoid enzymes being recognized by immune system and avoid early degradation. In addition, utilization of PEG in DDS are reported with enhanced delivery efficiency, prolonged circulation time and improved stability, especially active enzymes and peptides drug delivery. In this paper, we will conclude current studies about Pegylated DDS and their biomedical applications from both in vitro and in vivo studies.