Colloids for drug delivery to the brain

Abstract The field of neurodegenerative diseases have lately experienced significant advances. Despite that, we are still far from achieving the recovery of the patients. Nowadays there is more profound knowledge about the origins of the disorders and experimental therapies have become available. These attainments are encouraging, as the incidence of neurodegenerative diseases will notably increase in the coming years. This increases the demand for treatments that are more efficient. Up to now, the molecules that have proven to be effective cannot access the brain due to the restrictions posed by the blood-brain barrier (BBB). This review focuses on the most significant physiological approaches that used colloids as carriers to improve the delivery of therapeutics to the brain. In that sense, the general design considerations of colloids will be discussed with regard to the importance of size, surface properties, core composition, targeting and interaction with mucosal tissues. The improvement of the interaction with the BBB, the increase of drug bioavailability by the oral route and the nose-to-brain pathway illustrate the physiological efforts to circumvent the transport limitation of the BBB, and therefore they will be specially analysed.