Table 1.

Summary of the advantages and disadvantages of current methods used to circumvent the BBB for drug delivery to the brain

Strategy	Advantages	Disadvantages
Intracranial injection	Delivery to targeted brain regions Achieve therapeutic dose	Invasive Damage to healthy tissue
Drug Modification	Option for personalized medicine Noninvasive	Difficult to achieve therapeutic concentration in vivo Expensive and difficult to develop Non-targeted
Intranasal Delivery	Successful in pre-clinical studies	Drugs must travel great distance in the brain Difficult to achieve therapeutic concentrations in vivo
Global BBB disruption	Transient opening Can achieve therapeutic concentrations	Non-targeted – entire BBB is disrupted
Focused Ultrasound	Targeted to sub millimeter regions in the brain Non-invasive Therapeutic concentrations	Only relatively short term studies have been performed.