The diffusion coefficient changes with pH for a drug that ionises
the distribution coefficient= concentration of drug in oil/total concentration of drug in water (ionised + unionised)
Diffusion is the process of passive mass transport of molecules of one species through a medium
Which equation is used to describe rate of diffusion of drug through a membrane?
Henderson Hasselbalch equation
Fick's First Law
The rate of diffusion through a membrane is driven by the concentration gradient