Polymeric nanoparticles for drug delivery in glioblastoma: State of the art and future perspectives

Glioblastoma (GBM) is an aggressive, fatal and malignant primary brain tumor. Despite the current standard treatment for glioblastoma patients including neurosurgical resection, followed by concomitant radiation and chemotherapy, the median survival rate is only about 15 months. An unresolved challenge for current therapies is related to getting drugs through the blood-brain barrier (BBB), which hinders many chemotherapeutic agents from reaching tumors cells. Although a large amount of research has been done to circumvent the BBB and deliver drugs to the brain, with nanoparticles (NPs) taking the lead, the challenge is still high. In this regard, the BBB and how to transfer drug pathways through the BBB, especially using NPs, are introduced here. Afterwards, the latest advances in drug delivery, co-drug delivery, and combination modalities are described specifically for GBM treatments using natural and synthetic polymeric NPs and adjuvant therapies including hyperthermia, photodynamic therapy and also ketogenic regimens. In addition, receptor-mediated endocytosis agents that exist in endothelial capillary cells of the brain are explained. Lastly, future directions to finally deliver drugs through the BBB for GBM treatment are emphasized. It is the hope that this review can provide a number of practical pathways for the future development of BBB permeable nanochemotherapeutics against GBM.