Compendium of the most significant studies with reference to properties, intake, effects.

Trotta M, Gallarate M, Pattarino F, Morel S. Emulsions containing partially water-miscible solvents for the preparation of drug nanosuspensions. J Control Release. 2001 Sep 11;76(1-2):119-28. doi: 10.1016/s0168-3659(01)00432-1. Erratum in: J Control Release 2002 Apr 23;80(1-3):365.

Abstract. The aim of this study was to investigate the feasibility of partially water-miscible solvents, such as benzyl alcohol, butyl lactate and triacetin, to prepare drug nanosuspensions by a solvent quenching technique. Mitotane, which possesses very poor water solubility and low bioavailability, was used as model drug. Preparation was by emulsifying an organic solution of the drug in an aqueous solution of a stabilising agent followed by rapid displacement of the solvent from the internal into the external phase, provoking solid particle formation. To verify the influence of emulsion droplet size on the drug particle size, 0.1 or 0.2% of different emulsifiers (Tween 80, caprylyl-capryl glucoside or lecithin) and different homogenisation conditions (Ultra Turrax or a high pressure homogenizer at 200 or 1000 bar for three cycles) were used. In general, emulsion droplet size decreased with high pressure homogenization and on increasing the number of cycles. The size of drug particles, obtained after adding water at a constant rate, was dependent on the droplet size in the emulsion. Drug particles of approximately 80 nm were obtained using butyl lactate, supporting the hypothesis that drug particle formation by the emulsification diffusion process involves generating regions of local supersaturation. Because of the increase in available surface area, the dissolution rate of diaultrafiltrated suspensions increased greatly compared to commercial product.

Fiume, M. M., Heldreth, B., Bergfeld, W. F., Belsito, D. V., Hill, R. A., Klaassen, C. D., ... & Andersen, F. A. (2013). Safety assessment of decyl glucoside and other alkyl glucosides as used in cosmetics. International Journal of Toxicology, 32(5_suppl), 22S-48S.

Abstract  The Cosmetic Ingredient Review (CIR) Expert Panel assessed the safety of 19 alkyl glucosides as used in cosmetics and concluded that these ingredients are safe in the present practices of use and concentration when formulated to be nonirritating. Most of these ingredients function as surfactants in cosmetics, but some have additional functions as skin-conditioning agents, hair-conditioning agents, or emulsion stabilizers. The Panel reviewed the available animal and clinical data on these ingredients. Since glucoside hydrolases in human skin are likely to break down these ingredients to release their respective fatty acids and glucose, the Panel also reviewed CIR reports on the safety of fatty alcohols and were able to extrapolate data from those previous reports to support safety.

Dordevic, S. M., Cekic, N. D., Isailovic, T. M., Milic, J. R., Vuleta, G. M., Lazic, M. L., & Savic, S. D. (2013). Nanoemulsions produced by varying the type of emulsifier and oil content: effect of formulation and process parameters on the characteristics and physical stability/Nanoemulzije dobijene variranjem tipa emulgatora i udela masne faze: uticaj formulacije i procesnih parametara na karakteristike i fizicku stabilnost. Hemijska Industrija, 67(5), 795-810.

Abstract :The aim of the present study was to prepare oil-in-water nanoemulsions stabilized with a novel natural alkyl polyglucoside surfactant and to compare them with corresponding lecithin/polysorbate 80-based nanoemulsions in terms of physicochemical properties and physical stability. Nanoemulsions were prepared by high pressure homogenization, using 20, 30 and 40 mass% medium chain triglyceride as oil phase, and 4, 6 and 8 mass% lecithin/polysorbate 80 mixture (1/1) or caprylyl/capryl glucoside as emulsifiers. The effects of emulsifier type, emulsifier concentration and oil content were investigated with respect to changes in particle size, particle size distribution, surface charge and physical stability. The influence of production parameters (number of homogenization cycles, type of homogenization process, homogenization pressure) on particle size was also investigated. Analysis was performed by photon correlation spectroscopy, laser diffraction, zeta potential, pH and electrical conductivity measurements. All the produced formulations revealed a small droplet size ranging from 147 to 228 nm and a very narrow size distribution (polydispersity index range 0.072-0.124). Zeta potentials were found to be about -20 and -50 mV for nanoemulsions stabilized with lecithin/polysorbate 80 and caprylyl/capryl glucoside, respectively. The results obtained from the stability studies (6 months at 25[degrees]C and 1 month at 40[degrees]C) indicated that nanoemulsion stability was influenced by their composition. The results also suggested the most appropriate production parameters: 9 homogenization cycles, homogenization pressure of 500 bar and discontinuous process of homogenization.

JU Ya-Lin Chia Nan University of Pharmacy & Science Institutional Repository Evaluation of the stability and physical properties of nanostructured lipid carriers coated with astaxanthin  https://ir.cnu.edu.tw/handle/310902800/28968

Abstract. Astaxanthin encapsulated with nanostructured lipid carriers (NLCs) was investigated in this study. Three different surfactants including Tween 80 (Polysorbate 80), Poloxamer 188 (Pluronic F-68), Plantacare 810 (Caprylyl / capryl glucoside) and vitamin E were used to evaluate the stability of NLCs. The purpose of the present research was to avoid oxidation and degradation of the active ingredient. The nanostructured lipid carriers were prepared by high pressure homogenizers at 500 bar 5 cycles. The stable and physical property investigation of Astaxanthin loaded nanostructured lipid carriers were stored at 4, 25 and 45℃.. The experimental results show that nanostructured lipid carriers diameter were around 200 nm with a narrow polydispersity index (PdI) lower than 0.2, the mean value of zeta potential were more than -30 mV. The encapsulation efficiency of all formulations were 100%. The stability test results showed the surfactant of Plantacare 810 is better than Tween 80 and Poloxamer 188. The total NLCs recovery results of Plantacare 810 were more than 90% after 90 days. The surfactant of Plantacare 810 is can effectively reduce leak and degradation of active ingredient, and don’t add vitamin E to prevent oxidation of Astaxanthin. 

Kovacevic, A., Savic, S., Vuleta, G., Mueller, R. H., & Keck, C. M. (2011). Polyhydroxy surfactants for the formulation of lipid nanoparticles (SLN and NLC): effects on size, physical stability and particle matrix structure. International journal of pharmaceutics, 406(1-2), 163-172.

Abstract. The two polyhydroxy surfactants polyglycerol 6-distearate (Plurol®Stearique WL1009 – (PS)) and caprylyl/capryl glucoside (Plantacare® 810 – (PL)) are a class of PEG-free stabilizers, made from renewable resources. They were investigated for stabilization of aqueous solid lipid nanoparticle (SLN) and nanostructured lipid carrier (NLC) dispersions. Production was performed by high pressure homogenization, analysis by photon correlation spectroscopy (PCS), laser diffraction (LD), zeta potential measurements and differential scanning calorimetry (DSC). Particles were made from Cutina CP as solid lipid only (SLN) and its blends with Miglyol 812 (NLC, the blends containing increasing amounts of oil from 20% to 60%). The obtained particle sizes were identical for both surfactants, about 200 nm with polydispersity indices below 0.20 (PCS), and unimodal size distribution (LD). All dispersions with both surfactants were physically stable for 3 months at room temperature, but Plantacare (PL) showing a superior stability. The melting behaviour and crystallinity of bulk lipids/lipid blends were compared to the nanoparticles. Both were lower for the nanoparticles. The crystallinity of dispersions stabilized with PS was higher, the zeta potential decreased with storage time associated with this higher crystallinity, and leading to a few, but negligible larger particles. The lower crystallinity particles stabilized with PL remained unchanged in zeta potential (about −50 mV) and in size. These data show that surfactants have a distinct influence on the particle matrix struture (and related stability and drug loading), to which too little attention was given by now. Despite being from the same surfactant class, the differences on the structure are pronounced. They are attributed to the hydrophobic–lipophilic tail structure with one-point anchoring in the interface (PL), and the loop conformation of PS with two hydrophobic anchor points, i.e. their molecular structure and its interaction with the matrix surface and matrix bulk. Analysis of the effects of the surfactants on the particle matrix structure could potentially be used to further optimization of stability, drug loading and may be drug release. Copyright © 2011 Elsevier B.V.