An overview of current drug delivery strategies for glioblastoma treatment and barriers to progress

The current list of therapeutic options for glioblastoma (GB) is extremely short, and even fewer are the pharmacological approaches. The development of new chemotherapeutics is hampered by the peculiar location of GB, which is difficultly reached by drugs due to the biological barriers isolating it from the rest of the organism. For instance, monoclonal antibodies and several cytotoxic agents do not reach a sufficient distribution in the brain cancer, thereby not being able to exert their action on the malignant cells. To overcome this issue, novel drug delivery strategies must be explored. Specifically, the research on new materials, alternative administration routes, and site-specific targeting could provide a second chance to potent drugs with inefficient delivery to GB. This chapter, introducing the section New formulation approaches, provides an overview of the delivery strategies developed to the specific purpose of improving the accumulation of drug molecules in GB. After a brief introduction presenting the main biological barriers and current treatment options, an outlook of the most promising local, nose-to-brain, and systemic approaches will be provided, highlighting the role of the delivery systems in the improvement of the clinical outcome.