Some Drugs Like MDMA (Ecstasy, PKa 9

Multiple Choice

Some drugs like MDMA (Ecstasy, pKa 9.9) are so basic that they do not exist in any appreciable quantities in the neutral B form in the digestive tract. Yet, they are still absorbed. What factors allow for this?

A) Very large surface area of the GI tract
B) Rapid removal of any B molecules that do exist and transit the lipid bilayer
C) Movement of the liquid phases on both sides of the lipid bilayer
D) All of the above
E) None of the above