Nanostructured curcumin with choline and geranic acid ionic liquid (CAGE-IL): potential for incorporation into pharmaceutical gel formulations

Curcumin, a phytochemical, exhibits several biological properties and has been studied for the treatment of psoriasis. To facilitate its transdermal permeation, permeation enhancers such as choline and geranic acid ionic liquid (CAGE-IL) have been studied. From this perspective, the research effort entertained herein aimed at developing and evaluating the stability of an emulsion prepared with curcumin (phytochemical from Curcuma longa L.) and locust bean gum (extracted from the seeds of the carob tree, Ceratonia siliqua), with CAGE-IL as a facilitator of transdermal permeation. Stability studies were carried out for six months, with analyses being performed at time intervals of 0 (24 h), 30, 60, 90, and 180 days. The samples were kept at 40 ± 2 °C, with 75 ± 5% relative humidity (RH). The parameters analyzed were morphological characteristics, pH (5.8-6.0), and spreadability. The samples were shown to be stable during the timeframe studied, maintaining adequate physicochemical characteristics and meeting quality specifications for cutaneous applications. CAGE-IL, in addition to facilitating permeation of the active substance, also favored the formation of a stable emulsion encompassing nanosized particles (134.3 ± 2.6 nm) in a simple fashion and with only a few components.