Exploring bio-based alternatives to cyclopentasiloxane: Paving the way to promising silicone substitutes

Abstract

In recent years, significant efforts have been made to identify suitable alternatives for silicones commonly used in daily cosmetic products. However, green alternatives have faced challenges in replicating the unique properties of silicone-based formulations, particularly cyclopentasiloxane, which continues to be widely used.This study explores the potential of six biosynthesized esters (heptyl heptanoate, heptyl octanoate, heptyl decanoate, decyl heptanoate, decyl octanoate, and decyl decanoate) as possible substitutes for low-viscosity silicones (∼5 mPa). The research provides a thorough characterization of these esters, starting with an analysis of their physicochemical properties (pH, viscosity, surface tension, density, refraction index, spreadability, decomposition temperature, molar transition energy and cytotoxicity) and progressing to their incorporation into a commercial cosmetic formulation. The findings reveal that all tested esters show promise as silicone alternatives, effectively matching several key properties found in silicone-based formulations, such as cyclopentasiloxane or silicone oil, as well as a commercial alternative, Cetiol® CC. Regarding the physicochemical properties, all compounds exhibited a similar range of values. Notably, heptyl heptanoate and heptyl octanoate demonstrated superior cellular biocompatibility compared to cyclopentasiloxane. Upon incorporation into a commercial formulation, an in-depth analysis was conducted, examining organoleptic properties, dynamic light scattering (DLS) and microscopy, rheology, and textural attributes. All compounds displayed comparable performance, with the formulation containing heptyl heptanoate showing the highest spreadability and the least sticky sensation through rheological and textural analysis.The synthesized bio-based esters showed promising results as cyclopentasiloxane alternatives, paving the way for the development of cleaner and more sustainable cosmetic products.