Challenges in drug delivery to tumors of the central nervous system: An overview of pharmacological and surgical considerations

The majority of newly diagnosed brain tumors are treated with surgery, radiation, and the chemotherapeutic temozolomide. Development of additional therapeutics to improve treatment outcomes is complicated by the blood–brain barrier (BBB), which acts to protect healthy tissue from chemical insults. The high pressure found within brain tumors adds a challenge to local delivery of therapy by limiting the distribution of bolus injections. Here we discuss various drug delivery strategies, including convection-enhanced delivery, intranasal delivery, and intrathecal delivery, as well as pharmacological strategies for improving therapeutic efficacy, such as blood–brain barrier disruption.