Delivery of timolol through artificial membranes and pig stratum corneum

The in vitro passive and iontophoretic (applied current density: 0.5 mA/cm(2)) timolol (TM) permeability from a liquid solution through pig stratum corneum (SC) is found to be 0.9 +/- 0.5 x 10(-6) and 3.9 +/- 0.9 x 10(-6) cm/s, respectively. The in vitro iontophoretic TM delivery through the combination of artificial porous membranes with pig SC is investigated as well. When the meso-porous PES-30 membrane is applied, the SC mainly controls the TM delivery. When the microporous NF-PES-10 membrane is applied, both the membrane and the SC contribute to controlling the delivery of TM. When the microporous LFC 1 membrane is applied, the TM delivery is membrane controlled. In all cases, however, the efficiency of the TM delivery is low and would need to be improved for the development of a commercially viable product.