Captisol®: an efficient carrier and solubilizing agent for essential oils and their components

Abstract

AbstractEssential oils (EOs) and their individual components have several biological properties and are used in cosmetics, food and pharmaceutical industries. However, their application still presents a challenge owing mainly to their volatility and their poor aqueous solubility and stability. The aim of this study was to evaluate, for the first time, the ability of Captisol® (sulfobutylether‐β‐cyclodextrin, SBE‐β‐CD) and Captisol‐G® (sulfobutylether‐γ‐cyclodextrin, SBE‐γ‐CD) to encapsulate the main volatile components of six essential oils (EOs), to enhance the aqueous solubility of these EOs and to generate controlled release systems. The performance of these CDs was compared to hydroxypropyl‐β‐cyclodextrin (HP‐β‐CD) and γ‐cyclodextrin (γ‐CD), respectively. Formation constants (Kf) of the 40 inclusion complexes were determined by Static Headspace‐Gas Chromatography (SH‐GC). Then, Total Organic Carbon (TOC) was used to explore and quantify the efficiency of Captisol® and HP‐β‐CD to enhance the solubility of the six EOs. Finally, multiple headspace extraction (MHE) was applied to perform release studies. Kf values underlined the best binding potential of Captisol® towards all guests. Phase solubility diagrams showed that both Captisol® and HP‐β‐CD greatly increased the apparent solubility of EOs. The solubilizing potential was inversely proportionate to the EOs intrinsic solubility (SEO). Results indicated that Captisol® can successfully encapsulate EOs, increase their apparent aqueous solubility and decrease their release kinetics. Thus, Captisol® could be considered as a promising carrier to enlarge the application of EOs and their components.