PEGylated lipidic systems with prolonged circulation longevity for drug delivery in cancer therapeutics

Cancer therapy is hampered by severe dose-limiting side-effects that reduce the efficacy of cancer treatments. In improving cancer therapy, lipidic nanoparticle systems for drug delivery, such as liposomes and emulsions, have received much attention because they are capable of delivering their drug payload selectively to cancer cells and of circulating for a long period in the bloodstream. The physicochemical properties of particles are crucial for prolonging their longevity in the circulation. PEG modification, PEGylation of particles is one of the methods able to provide this functionality. This review provides an overview of current strategies for more effective cancer therapy using PEGylated lipidic particle systems for drug and gene delivery and for their improvement in the future. Here, we focus on cancer treatment via systemic injection of drugs or genes capable of prolonged maintenance in the circulation in PEGylated lipidic particles with passive targeting. In addition, we discuss the requirements for longevity in the circulation even for drug systems with active targeting using particles with a tumor-specific moiety.