PEGylated drug delivery systems in the pharmaceutical field: past, present and future perspective

Target-site drug delivery systems are gaining interest in the pharmaceutical field due to their great advantages, such as higher drug dosing capacity and better bioavailability. However, some existing problems need to be overcome. An example, is the interaction between blood proteins and drug delivery systems. A potent candidate to approach the mentioned problem is based on polyethylene glycol (PEG) surface modifications. This polymer acts as a protector against the external possible interactions with other compounds, making targeted delivery possible. Diseases such as cancer, diabetes, hemophilia and pain treatment can benefit from these new systems. This review aims to give an overview of drug delivery systems based on PEGylation as surface modification as the pharmaceutical approach. Moreover, a deeper insight into the properties of PEG and its advantages is given, as well as a brief overview of present therapies based on this technology.