Electromotive administration of oxybutynin into the human bladder wall

Purpose: To compare concentrations of oxybutynin in the human bladder wall after either passive delivery (PD) or electromotive administration (EMDA). Materials and Methods: Tissue sections of human bladder were inserted into a diffusion cell with urothelium exposed to the donor compartment containing oxybutynin (4.5 mg. in 100 ml. NaCl 0.45%) and an anode. Twelve paired experiments, ''current 5 mA/no current'', were conducted over 15 minutes. Oxybutynin tissue contents were measured and tissue viability, morphology and oxybutynin stability were assessed. Results: Mean oxybutynin tissue concentrations were 3.84 mu g./gm. in samples exposed to EMDA and 0.87 mu g./gm. in samples exposed to PD (p = 0.0006). The mean coefficients of variation were 57.85% in EMDA experiments and 89.78% in PD experiments. Tissues were viable and undamaged histologically and no oxybutynin structural modification was observed. Conclusions: EMDA enhances oxybutynin administration into viable bladder wall and reduces the variability in drug delivery rate.