Systems approach to study of solute transport across membranes using suspension cultures of mammalian cells III: steady-state diffusion models.

General physical models are derived for the diffusional transport of drugs across membranes of mammalian cells in culture suspension. These models represent different sets of possible physical processes taking place during the transport of a drug molecule. Once the diffusing species reaches the cell barrier, it may gain entrance to the cell kinetically by one of the principal quasisteady-state mechanisms, all of which assume the cell membrane to be an integral part of the total barrier.