Drug delivery to the brain CNS Flashcards
(16 cards)
Main barrier that prevents drugs from reaching brain ?
Blood brain barrier (BBB)
Why is BBB both advantage and disadvantage in drug delivery ?
Protects CNS from harmful substances BUT also makes it hard for useful drugs to reach brain tissue
Three approaches to bypass BBB
1)Intraspinal delivery
2) Intranasal delivery
3) Polymer implants
2 main types of Intraspinal delivery
1) Epidural
2) Intrathecal
Where is drug injected intrathecal therapy ?
Subarachnoid space containing Cerebrospinal fluid (CSF)
What are intrathecal injections mainly used for ?
Pain relief, antibiotic, and cytotoxic (kills cancer cells) drug delivery near the brain
Maximum volume for an intrathecal injection ?
10mL
Device used to avoid repeated intrathecal injections?
Implanted subcutaneous pump e.g Medtronic Synchromed (Continous medication that’s always being given)
How does intranasal (nose-to-brain) route deliver drugs to the brain ?
Through Olfactory and trigeminal nerves
What is the Gliadel® wafer (Polymer implant ) used for ?
Local delivery containing Chemotherapy drug Carmustine to treat brain tumors
What type of polymer is used in Gliadel® wafers?
: Polyanhydrides – specifically P(CPP-SA) copolymer
benefit of using P(CPP-SA) in brain implants ?
allows controlled degradation + drug release while protecting the drug.
How many Gliadel® wafers can be inserted at a time?
8 wafers maxmimum
Three barriers protecting the brain ?
blood-brain barrier (BBB), the blood-CSF barrier (BCB), and arachnoid barrier.
Features of the BBB which help block drug entry ?
Tight junctions, absence of fenestrations (tiny pores) in brain capillaries
Five ways drugs can cross the BBB ?
1) Passive diffusion
2) Active transport
3)
