Fick's Laws of Diffusion:
A) First Law:
States that the rate of diffusion is proportional to the concentration gradient.
Describes the flux of molecules:
J is the flux, D is the diffusion coefficient, is the concentration gradient.
B) Second Law:
Explains that diffusion causes changes in concentration over time.
Permeability Coefficient (P):
Determines the rate at which a drug diffuses across a membrane.
Partition Coefficient (K):
Ratio of concentrations of a compound in a mixture of two immiscible phases at equilibrium.
Factors Affecting Diffusion Principles in Biological Systems:
Molecular size, lipophilicity, ionization state, and membrane properties.