Related Experiment Video
Updated: Aug 20, 2026
Real-time Iontophoresis with Tetramethylammonium to Quantify Volume Fraction and Tortuosity of Brain Extracellular Space
Published on: July 24, 2017
Response surface methodology to investigate the iontophoretic delivery of tacrine hydrochloride
Rashmi S Upasani1, Ajay K Banga
1Department of Pharmaceutical Sciences, School of Pharmacy, Mercer University, Atlanta, Georgia 30341, USA.
Purpose:
The objective of this work was to apply response surface approach to investigate the main and interaction effects of delivery parameters for iontophoretic delivery of tacrine HCl in vitro.
Methods:
Iontophoresis was used to deliver tacrine HCl across rat skin. Experiments were performed according to Box-Behnken design to evaluate effects of drug concentration (X1), current density (X2), and donor buffer molarity (X3) on cumulative drug delivered in 24 h (Y1), 6 h (Y2), iontophoretic flux (Y3), and post-iontophoretic flux (Y4).
Results:
Mathematical model for Y1 was Y1 = 0.653 + 0.163 * X1 + 0.456 * X2 - 0.156 * X3 + 0.190 * X1X2 + 0.139* X3X3. Response surface plot indicated that at low level of X2 (0.1mA/cm2), X1 had little effect on Y1. However, at high level of X2 (0.5 mA/cm2), Y1 significantly increased from 0.75 mg/cm2 to 1.46 mg/cm2 when X1 increased from 1% to 9%. Regression equations predicted responses for Y1 to Y4, for optimal formulation, which were in reasonably good agreement with experimental values.
Conclusions:
Experimental design methodology revealed an interaction between drug concentration and current density, which would have been difficult to predict from one factor at a time classic experimental approach.
