A Review on Novel Techniques for Drug Delivery to the Brain
Drug delivery to brain is still a challenging task due to the presence of the blood–brain barrier (BBB), a very restrictive barrier mainly composed of tightly sealed endothelial cells. The anatomy and physiology of BBB strictly regulates the brain access and clearance of endogenous and exogenous molecules from the systemic circulation. It is estimated that more than 98% of the new discovered central nervous system (CNS) potential drugs does not cross the BBB, failing to achieve therapeutic concentration within the brain parenchyma. Recent developments in the field of molecular biology enabled scientists to better understand the BBB and thus delivery of drugs to the brain, particularly under different pathological conditions. The aims of this Review are to outline current research in the field of brain barriers, the main advances made since 2000, the barriers to progress, and to recommend research priorities and the resources needed to advance the field. Applications of nanotechnology in drug transport, receptor-mediated targeting and transport, and finally cell-mediated drug transport will be discuss in the review. The challenge of delivering an effective dose of drug to the brain is formidable; solutions will likely involve multiple strategies that take into account the novel drug delivery systems as well as BBB biology.