Liposome-based targeted delivery of anticancer drugs for effective therapy of brain tumors

Abstract

Abstract The treatment of brain cancers is hampered by inadequate delivery of therapeutic substances due to the presence of several barriers. For efficient treatment of brain cancers, it is essential to carry therapeutic drugs across the specialized vascular barrier of the brain, the blood–brain barrier (BBB), which makes a formidable challenge to the entry of many drugs and foreign substances to brain. Apart from the BBB, the blood–brain tumor barrier and comparatively lower enhanced permeability and retention effect of brain tumors restrict entry of conventionally administered anticancer drugs to brain and brain tumors. In recent years, nanotechnology and nanocarrier-based drug delivery approaches have received greater scientific interest and been considered a powerful tool for delivering therapeutic molecules to target sites. Liposomes are vesicular nanodrug delivery systems made up of concentric lipid bilayers having the capacity to carry both hydrophilic and lipophilic drugs. They have historically been used as drug carrier systems due to their excellent biocompatibility, low toxicity, easy preparation, and commercial availability. Moreover, liposome surfaces can be modified with different ligands to target-specific disease sites and escape the immune system to prevent early clearance from the body. Though use of liposomes for effective and targeted brain-drug delivery is not a common clinical practice, various liposomal formulations are either approved for clinical use or in clinical trial phases. This chapter describes different barriers to brain-drug delivery and strategies to overcome those barriers with particular focus on liposomal drug delivery systems for targeting brain cancers.