An update on the role of nanovehicles in nose-to-brain drug delivery.

A quantitative analysis has cast doubt over the limited advantages provided by particles for nose-to-brain (NTB) drug delivery. Thus, it is imperative to identify the role of nanovehicles in NTB drug delivery. If nanocarriers are used merely as an option to improve various properties of the drugs or the formulations, it is difficult for them to outperform conventional formulations, such as solutions or gels. However, nanovehicles bring about special features, such as maintenance of the solubilized state of drugs, sustained or delayed release, and enhanced penetration because of surface modifications, all of which lead to enhanced NTB delivery efficiency.