Delivery of ONPs through the Blood-Brain Barrier BBB

3 Delivery of ONPs through the Blood-Brain Barrier (BBB) 

Another important application of ONPs is the delivery of xenobiotics into the brain, by going through the blood-brain barrier (BBB). Several papers describe this use [94-97], although further innovation in this field is required as systems currently being investigated still have little absorption and short half-lives. One way around this problem has been found by giving nanoparticulate systems for brain delivery by nasal administration, thus avoiding first-pass metabolism. 

Mishra and collaborators have described the use of ONPs to deliver azidothymi-dine (AZT) into the brain [98]. AZT is an antiviral employed classically for therapy against HIV its high water solubility diminishes its chances of crossing the BBB. ONPs enhance BBB crossing by protecting it and making it more oil-soluble. AIDS, however, remains a little explored use for ONPs. 

Lipid nanoparticles have also been used for gene delivery. Findings with this type of ONP, as well as their limitations, are explained in Li and Szoka s review [101], emphasizing the size requirements to obtain good penetration. 

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