PEGylated polylactide (PLA) and poly (lactic-co-glycolic acid) (PLGA) copolymers for the design of drug delivery systems

Background: PEGylated polylactide (PLA) and poly (lactic-co-glycolic acid) (PLGA) copolymers are biodegradable polyesters, widely employed in the last decades for the design of drug delivery systems such as polymeric hydrogels and nanocarriers (e.g. micelles and nanoparticles). The coupling with polyethylene glycol (PEG) offers some advantages with the respect to PLA and PLGA, including a higher hydrophilicity and a prolonged retention time for nanoparticulate systems, as well as the possibility of preparing thermoresponsive hydrogels. A large variety of pharmacologically active-compounds (small molecules, natural compounds or biomolecules such as proteins, peptides, oligonucleotides) has been formulated and delivered through PEGylated PLA or PLGA copolymers. Due to the high number of papers recently published about the use of these biodegradable copolymers in drug delivery, PEGylated PLA or PLGA copolymers are being still attractive. Their potential applications have been also broadened by the developing of ligand-functionalized copolymers, enabling an “active drug targeting” for nanoparticulate systems. Area covered: The present review summarizes the recent advances in drug delivery systems based on PEGylated PLA or PLGA copolymers, focusing on self-assembled micelles and thermoresponsive hydrogels as well as nanoparticles. A particular consideration has been given to functionalized PEGylated PLA/PLGA nanoparticles for active drug delivery. Expert opinion: Further advances in the design of PEGylated PLA/PLGA delivery systems will be beneficial for an improved drug release and targeting in the light of novel personalised therapeutic strategies. © 2019, The Korean Society of Pharmaceutical Sciences and Technology.