VALIDATION AND TESTING OF A NEW IONTOPHORETIC CONTINUOUS-FLOW THROUGHTRANSPORT CELL

A new continuous flow through transport cell is presented. The design is based on a minimisation of contributions of the cell conformation a nd experimental protocol to the overall transport kinetics. The system is validated by measuring the washout period of methylene blue and ap omorphine. Preliminary results on the iontophoretic transport of apomo rphine across human stratum corneum are presented. These data are used to calculate the deviation of the measured apparent flux from the cal culated intrinsic flux across the membrane. The steady state iontophor etic flux was 90+/-6 nmol cm(-2) h(-1) when a 15 mM apomorphine soluti on was applied in the anodal chamber at a current density of 500 mu A cm(2). At any point in time the contribution of the cell to the transp ort rate was less than or equal to 3%. The supporting membrane does no t contribute significantly to the overall transport rates. Sink condit ions are guaranteed at a flow rate greater than or equal to 6.5 ml h(- 1). For this new transport cell it can be concluded that the apparent flux that was measured, at validated experimental conditions, is a rel iable estimate for the intrinsic flux. (C) 1998 Elsevier Science B.V.