Equations describing passive transport through vesicular membranes

A theoretical description of the kinetics of the passive transport of both lipophobic and lipophilic nonelectrolytes, weak acids, and weak bases through membranes of large unilamellar vesicles is discussed. Equations are derived which may be used to obtain permeability coefficients and predict the extent of LUV entrapment of permeant molecules. Theoretical curves are generated to illustrate the difference between lipophobic and lipophilic permeation. By applying a diffusional approach rather than a simple first order kinetic approach to the problem of passive transport, some of the inconsistencies observed in other works are corrected.