PLA/PLGA nanoparticles for delivery of drugs across the blood-brain barrier

The blood-brain barrier (BBB), which protects the central nervous system (CNS) from unnecessary substances, is a challenging obstacle in the treatment of CNS disease. Many therapeutic agents such as hydrophilic and macromolecular drugs cannot overcome the BBB. One promising solution is the employment of polymeric nanoparticles (NPs) such as poly (lactic-co-glycolic acid) (PLGA) NPs as drug carrier. Over the past few years, significant breakthroughs have been made in developing suitable PLGA and poly (lactic acid) (PLA) NPs for drug delivery across the BBB. Recent advances on PLGA/PLA NPs enhanced neural delivery of drugs are reviewed in this paper. Both in vitro and in vivo studies are included. In these papers, enhanced cellular uptake and therapeutic efficacy of drugs delivered with modified PLGA/PLA NPs compared with free drugs or drugs delivered by unmodified PLGA/PLA NPs were shown; no significant in vitro cytotoxicity was observed for PLGA/PLA NPs. Surface modification of PLGA/PLA NPs by coating with surfactants/polymers or covalently conjugating the NPs with targeting ligands has been confirmed to enhance drug delivery across the BBB. Most unmodified PLGA NPs showed low brain uptake (<1 %), which indirectly confirms the safety of PLGA/PLA NPs used for other purposes than treating CNS diseases.