Molecules of a drug move through a polymer membrane and into blood that flows next to the membrane.
a. What kind of mass transfer (molecular diffusion, or convection) occurs in the polymer, and which occurs in the blood phase?
b. If the mass transfer inside the polymer represents the limiting resistance, how would each of the following affect the overall rate of mass transfer? In each case, explain your answer.
i. Increase the flow rate of blood
ii. Modify the drug to decrease its molecular size