[Studies on the distribution and transport kinetics in membrane and distribution models]

The concentration-time dependence of two weak acids (salicylic acid, benzoic acid), one weak base (benzocaine) and one neutral agent (acetanilid) has been studied in membrane or distribution models by polyacrylat-D 340-membranes or cyclohexane phases. The transport rate constants of outflow from the donator compartment or influx into the acceptor compartment as well as the distribution coefficients membrane/water or cyclohexane/water had been calculated from the concentration-time courses. In contrast to the polyacrylate membrane, the outflow from the donator compartment and the influx into the acceptor compartment proportionate to the corresponding distribution coefficient with the use of the cyclohexane phase. The influx into the acceptor compartment is in the polyacrylate membrane delayed by interactions between the membrane and the permeant. The membrane/water distribution coefficients figured out from the permeation test correspond with values formerly derived from equilibrium tests.