Solubilization of Span 80 Niosomes by Sodium Dodecyl Sulfate

Abstract

The solubilization process of sorbitan monooleate (Span 80) niosomes, formed by sonication, by addition of the anionic surfactant sodium dodecyl sulfate (SDS) was studied in this work. The main parameters studied were the optical density at 350 nm wavelength, particle size distribution, ζ-potential, and the concentration of SDS monomers in the dispersions. Results allowed us to differentiate the stages of the solubilization process for each formulation, as well as to identify critical points of saturation by the SDS adsorbed in the bilayer, and the total niosome solubilization. The composition of these critical points turned out to be independent from time, thus allowing the construction of the pseudophase equilibrium diagram, where the lines of saturation and total solubilization of niosomes follow a linear behavior. Monomeric SDS concentration measurement corroborates the composition of the critical point of total solubilization and confirms that the niosome solubilization is a micellization process in which any amount of SDS added above critical values of total solubilization will increase the mixed micelle concentration, keeping constant the concentration of SDS monomers in solution. The results of this study shed light on further research of this biodegradable system regarding its possible use in multiple sustainable applications.

Preparation of Water-in-Oil Nanoemulsions Loaded with Phenolic-Rich Olive Cake Extract Using Response Surface Methodology Approach

“…The nanoemulsions were characterized by the following methods described in previous studies [16,21,23,32,33] and explained in the Supplementary Data S1: (i) droplet size distribution, mean droplet diameter, and polydispersity index (PDI) by dynamic light scattering using a Zetasizer Nano ZS (Malvern Instruments Ltd., Malvern, U.K.); (ii) TPC using the Folin-Ciocalteu standard method; (iii) AA by the DPPH method [34]; (iv) TPC and AA retained within the aqueous phase, following the method developed by Regan and Mulvihill [23,35]. All measurements were performed at least three times.…”

Playing Favorites: Preferential Adsorption of Nonionic over Anionic Surfactants at the Liquid/Liquid Interface

“…Surfactant mixtures are important for a variety of applications that rely on complex surface chemistries, such as pharmaceutical drug delivery systems, − environmental oil remediation techniques, − and the development of various industrial polymer films. − Many of these applications specifically utilize mixed systems to provide control over interfacial properties at the boundary between oil and water, such as the surface structure and electrostatic charge of the interface. Mixed systems containing nonionic components have been shown to be particularly promising for various biological surface applications when mixed with common anionic surfactants, as several nonionic surfactants have been found to be a safe alternative for other surfactants shown to be harmful when used in environmental and biological applications. − …”

“…The specific surfactants of interest in this study are nonionic sorbitan monooleate (Span-80) and anionic dioctyl sulfosuccinate sodium salt (AOT). Span-80 has been a surfactant of interest for environmental remediation and industrial applications due to its nontoxicity. , AOT is commonly used in oil spill dispersant mixtures and other applications that require a low surface tension between oil and water due to its highly surface-active nature. ,, Understanding how Span-80 and AOT behave together in a mixed binary surfactant system is important for evaluating Span-80’s performance as a nontoxic ingredient when used in mixed systems. Because the efficacy of these mixed-system applications can depend on changing surface properties due to surfactant adsorption over time, − it is important to understand the molecular structure of mixed-system surfaces as a function of time.…”

“…Span-80 has been a surfactant of interest for environmental remediation and industrial applications due to its nontoxicity. 20,21 AOT is commonly used in oil spill dispersant mixtures and other applications that require a low surface tension between oil and water due to its highly surface-active nature. 24,25,29 Understanding how Span-80 and AOT behave together in a mixed binary surfactant system is important for evaluating Span-80's performance as a nontoxic ingredient when used in mixed systems.…”

Separation of sodium lactate from Span 80 and SDS surfactants by ultrafiltration

“…However, the addition of ionic surfactants to the niosome dispersions can lead to the complete solubilization of vesicles. The solubilization process of Span 80 niosomes by addition of SDS has been recently studied [22]. It was identified as a three-stage micellization process: SDS adsorption until saturation, intensification of the bilayer solubilization by mixed micelles formation, and complete bilayer solubilization by micellization.…”