Search

Objective To demonstrate the in vitro activities of panthenol, palmitoylethanolamide (PEA), and niacinamide (NAM) and determine the biophysical properties, clinical safety, tolerability together with efficacy of two developmental anti‐redness (AR) formulations containing these ingredients, in alleviating facial redness associated with winter xerosis in healthy volunteers with sensitive skin. Methods The anti‐inflammatory and skin protective properties of panthenol, PEA and NAM were evaluated in vitro. The physical properties of the AR formulations were analysed using measurement of water vapour transport rate (WVTR) and infrared spectroscopy. Clinical studies were performed between the months of December and April (2014–2015) with efficacy assessed during the winter. Facial redness, irritation, sensitization potential, photo‐irritation, and photo‐sensitization were evaluated. Self‐assessed adverse reactions were reported in diaries of use. Results Panthenol and PEA reduced prostaglandin E2, interleukin‐6, and thymic stromal lymphopoietin levels in vitro, while NAM induced nicotinamide adenine dinucleotide (NAD) levels and the keratinocyte differentiation markers: filaggrin (2‐fold increase, P, This article demonstrates the in vitro activities of panthenol, palmitoylethanolamide (PEA), and niacinamide (NAM) and determines the biophysical properties, clinical safety, tolerability together with efficacy of two developmental anti‐redness formulations containing these ingredients, in alleviating facial redness associated with winter xerosis in healthy volunteers with sensitive skin.

Objectives The present work analyzed the antioxidative activity of phenol-based antioxidants by using an Electron Spin Resonance method to predict the activity and stability of these antioxidants in cosmetic products. Methods The Antioxidative Power (AP) method was chosen to measure both the capacity and kinetics of an antioxidative reaction by detecting the DPPH (diphenylpicrylhydrazyl) radical. The antioxidative capacity (wc) relates to the amount of free radicals that can be reduced, whereas the antioxidative reactivity (tr) relates to the reaction speed and offers a fingerprinting of the redox state of the antioxidant molecules. Fifteen phenolic molecules, have been analyzed. They differed in the position of the hydroxyl groups and substituents on the aromatic ring. The AP of two distinct formulations containing hydroxytyrosol are presented as well as three phenol based antioxidants within the same formulation vehicle. Results The rate at which phenol (ArOH) reacts with DPPH radicals, defined by the term reactivity (tr) in this paper, was dependent upon the bond dissociation enthalpy (BDE) of the OH bond. Molecules having weak OH bonds and consequently low BDE values showed high antioxidant reactivity. On the other hand, the capacity factor (wc), which is the concentration of phenol required to reduce a fixed concentration of DPPH radical, depends on the number and position of hydroxyl groups. The results showed that ortho and para positions of the two hydroxyl groups are important for higher capacity. If one of the two hydroxyl-groups is blocked by methylation, both the antioxidative capacity and reactivity are reduced, mainly for ortho disubstituted compounds. The presence of a vinylic side chain improved reactivity and capacity tremendously. AP values may be useful in formulation design when identifying antioxidants that are likely to be physically and chemically stable. The importance of optimization of the formulation vehicle itself for a given antioxidant is also illustrated. Conclusion Based on the presented findings, it is possible to predict the antioxidative performance of a phenol-based molecule and its stability and oxidation-resistance within a cosmetic formulation. This is essential for antioxidant containing dermal formulations designed to combat skin ageing. This article is protected by copyright. All rights reserved.