Getting into the Brain: Are We in Yet or Just Knocking at the Door?

Nanomedicine, a promising addition to the spectrum of biomedicine, has viewed countless breakthroughs in the implementations of "site-specific" drug delivery. The promises of nanomedicines revolve around their unique physicochemical properties that permit the transport of therapeutics to the desired site of action, improve the pharmacokinetic endpoint, maximize the pharmacological influence of treatment, and overcome the limitation of remedies that otherwise would impede the therapeutic effectiveness. One of most insurmountable challenge possessed by conventional drug-delivery in getting therapeutics across the central-nervous-system is to conquer the harsh passage of the blood-brain barrier (BBB). Many published studies revealed BBB to be a complex, dynamic interface that acclimatizes to the needs of the central nervous system (CNS). These physical and biochemical barriers pose a significant challenge to the effective management of brain-related disorders such as neurodegenerative diseases. This challenge is widely accepted and defeated with the advent of a new class of brain-targeted nanomedicines. This review is an effort to overview the key research trends in nanotechnology over the past decade concerning the BBB as a regulatory interface and factors affecting CNS drug delivery. The review further summarized the specific diversity of various nanomedicinal approaches, the critical and elementary structural component of their design, the surface engineering of vehicles carrying drug at the nanoscale, selected current clinical successes, and future prospects along with hidden perils.