Controlled transdermal delivery of oxycodone by pulsed iontophoresis: In vitro and in vivo evaluations

The imperative challenges in transdermal iontophoresis (IP) are irritation, skin polarization, and patient discomfort. In this paper, we studied the IP delivery of oxycodone (OXC) using continuous direct current (CDC) and pulse depolarization current (PDC) current protocols. The different current protocols (CDC, PDC1, PDC2, and PDC3) have been employed to investigate the in vitro transdermal IP of OXC through the rat skin. Moreover, other effective factors including the formulation pH, the magnitude of applied current density, and the NaCl concentration were optimized to obtain the best performance of IP. The in vitro permeation experiments demonstrated that the cumulative amount of permeated OXC after 24 h (Q_{24 h}) in the presence of the studied current protocols decreases in the following order: CDC > PDC3 > PDC2 ≈ PDC1. The permeation of OXC in the presence of CDC was evidently enhanced compared to that of the PDC3. Also, the experimental data were fitted using the Peppas-Sahlin model. Finally, in vivo experiments revealed that a statistically significant increase in the permeated OXC in the presence of IP technique (CDC, and PDC3) as compared to the control experiment. The study can pave the way for developing IP delivery systems using PDC.