Problem:
I have just started reading up on structure-based methods for drug design (this is completely not my field so apologies for stupid questions that will be coming along!)
Clearly, some drugs are designed to target the central nervous system. However, I understand that the extracellular fluid of the central nervous system is separated from the blood by the "blood-brain barrier" which restricts the passage of large molecules between the two systems.
Explain how do you design a drug to be delivered to the CNS?