Ethosomes® and transfersomes® containing linoleic acid: physicochemical and technological features of topical drug delivery carriers for the potential treatment of melasma disorders.

Two vesicular colloidal carriers, ethosomes® and transfersomes® were proposed for the topical delivery of linoleic acid, an active compound used in the therapeutic treatment of hyperpigmentation disorders, i.e. melasma, which is characterized by an increase of the melanin production in the epidermis. Dynamic light scattering was used for the physicochemical characterization of vesicles and mean size, size distribution and zeta potential were evaluated. The stability of formulations was also evaluated using the Turbiscan Lab® Expert based on the analysis of sample transmittance and photon backscattering. Ethosomes® and transfersomes® were prepared using Phospholipon 100 G®, as the lecithin component, and ethanol and sodium cholate, as edge activator agents, respectively. Linoleic acid at 0.05% and 0.1% (w/v) was used as the active ingredient and entrapped in colloidal vesicles. Technological parameters, i.e. entrapment efficacy, drug release and permeation profiles, were also investigated. Experimental findings showed that physicochemical and technological features of ethosomes® and transfersomes® were influenced by the lipid composition of the carriers. The percutaneous permeation experiments of linoleic acid-loaded ethosomes® and transfersomes® through human stratum corneum-epidermidis membranes showed that both carriers are accumulated in the skin membrane model as a function of their lipid compositions. The findings reported in this investigation showed that both vesicular carriers could represent a potential system for the topical treatment of hyperpigmentation disorders.