Evaluation of the efficacy of proprietary niosomes as enhancers of skin permeability of plant extracts: an in vitro study
The development of tailored niosome models as carriers for skin permeation and absorption has been indicated as a possible solution to vector plant extracts and phytocompounds that are poorly used for cosmetic and topical medical devices due to low or unknown skin absorption. The present study investigated the effects of a niosome model in increasing skin absorption of a wide range of phytocompounds and plant extracts, to determine whether a tailored niosome solution would result in an increased delivery of target reference molecules, to give indication of an effective absorption of phytocomplexes.
Five different molecules (Quercetin, 7-Hydroxymatairesinol, Formononetin, Biochanin A, Cannabidiol) from four different plant extracts (Ginkgo biloba, Picea abies, Trifolium pratense, Cannabis sativa) were tested in an in vitro model of skin absorption in order to determine and quantify the difference in permeation kinetics between the free extracts as is and the same extracts loaded in the tailored niosomes. Concentration of reference molecules in the artificial skin model were determined by HPLC/UPLC at several end points. Results indicated an increase in the amount of compounds absorbed by the skin, with statistically significant results for four of the five molecules, hinting at direct efficacy in increasing skin permeation for a wide range of complex phytocompounds.
Medicinal plant extracts are known for their clinical efficacy and can be concentrated and standardized properly. However, these extracts are often impossible to be used in cosmetic applications due to their low or unknown absorption properties, especially in regards to skin permeation. The use of these phytocomplexes, which are often characterized by complicated molecules, with high molecular weight and an undesirable hydro-lipid coefficient in formulations, can also be hindered by other features, such as an improper transfer of the colour or specific insolubility.
Niosomes were first described in the late seventies (1, 2) and qualify as a possible molecular carrier that would increase skin permeation and uptake (1). Niosomes are structurally similar to liposomes, but their outer bilayer is composed of non-ionic surfactants and/or cholesterol instead of phospholipids. Given their structure, niosomes can store both hydrophilic actives within the space enclosed in the vesicle, and hydrophobic actives embedded inside the bilayer. Niosomes are extremely flexible and vary in size between the nanoscale and the low-end of the micro-scale.