Polymeric nanospheres as strategy to increase the amount of triclosan retained in the skin: passive diffusion vs. iontophoresis

Abstract

The aim of this study was to evaluate the passive and iontophoretic permeation of triclosan in human skin using a triclosan solution and triclosan-loaded cationic nanospheres in order to determine which of the two strategies is more effective in allowing the deposition of triclosan within the skin. Triclosan-loaded nanospheres were prepared by the emulsification-solvent displacement technique using aminoalkyl methacrylate (Eudragit® RL 100) as polymer matrix. Nanospheres of 261.0 ± 15.1 nm with a positive surface charge (Ψz = 26.0 ± 3.2 mV) were obtained. Drug loading was 62.0 ± 1.7%. Results demonstrated that the amount of triclosan retained within the skin was significantly greater (8.5-fold) when this was encapsulated into cationic nanospheres and administered by passive diffusion than when the triclosan solution was employed. The amount of triclosan retained within the skin when the cationic nanospheres were administered by iontophoresis was 3.1-fold greater than when the triclosan solution was administered by passive diffusion. Iontophoresis proved to be effective in enhancing the passage of triclosan in solution throughout the skin, whereas the triclosan nanospheres could achieve a local effect by forming a controlled release dermal depot.