Page 15 - controlled drug delievery

2- Partition Coefficient

• Drugs should have a balanced oil/water partition coefficient (K)
to permeate through the membrane.

• Optimum activity is observed at K ≈ 1000/1 in 1-octanol/water.

• Drugs with higher or lower K values are poor candidates for
formulation as SR delivery systems. Why?
Higher values------------- high biological membrane permeability,
low solubility, might suffer lipid tissue accumulation.

• The partition coefficient of the drug between the formulation
matrix/membrane and the external aqueous medium is another
consideration.