Identification of an emulsifier and conditions for preparing stable nanoemulsions containing the antioxidant astaxanthin

• Published in: International journal of cosmetic science Vol. 34; no. 1; pp. 64 - 73
• Main Authors: Kim, D-M., Hyun, S-S., Yun, P., Lee, C-H., Byun, S-Y.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.02.2012; Wiley
• Subjects: Antioxidants - chemistry; Applied sciences; astaxanthin; Biological and medical sciences; Chemical industry and chemicals; Cosmetics, toiletries; Emulsions - chemical synthesis; Emulsions - chemistry; Exact sciences and technology; General pharmacology; high-pressure homogenization; Medical sciences; Microscopy, Electron, Transmission; nanoemulsion; Nanostructures - chemistry; Nanostructures - ultrastructure; Particle Size; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Washing products. Cosmetics and toiletries. Perfumes; Xanthophylls - chemistry; zeta potential; Cosmetic; Scanning electron microscopy; Particle size; Homogenization; zeta potential; Emulsifier; Antioxidant; Electron microscopy; nanoemulsion; Operating conditions; Surface structure; astaxanthin; Particle size distribution; Pressure effect; Transmission electron microscopy; Storage stability; Formulation; Morphology; Concentration effect; Electrokinetic potential; Qualitative analysis; Freeze etching; Carotenoid; high-pressure homogenization
• ISSN: 0142-5463; 1468-2494
• DOI: 10.1111/j.1468-2494.2011.00682.x

Synopsis In this study, oil‐in‐water nanoemulsions of astaxanthin were prepared by high‐pressure homogenization. The influence of emulsifying conditions including emulsifier type, concentration, passing time, astaxanthin concentration and coantioxidants were optimized. The stabilities of nanoemulsions were measured using zetasizer, FF‐SEM, TEM, colorimeter and particle size analyzer. The mean diameter of the dispersed particles containing astaxanthin ranged from 160 to 190 nm. The size distribution was unimodal and extended from 100 to 200 nm. The nanoemulsions prepared with glyceryl citrate/lactate/linoleate/oleate (glyceryl ester) had smaller particle size and narrower size distribution than the emulsion prepared with hydrogenated lecithin. Stable incorporation of astaxanthin in nanoemulsion was performed and checked using HPLC, FF‐SEM and TEM. The nanoemulsion was not significantly affected during storage under light and thermal condition for one month indicating that the nanoemulsion had a zeta potential of less than −41 mV, indicating a stable colloid. Résumé Dans cette étude des nano émulsions d’astaxanthine sont préparées par homogénéisation à haute pression. Les conditions d’émulsification sont optimisées en terme de type et de concentration d’émulsionnants, de temps de passage, de concentration d’astaxanthine et de co‐antioxydants. Les stabilités des nano émulsions sont évaluées à l’aide d’un zetasizer, de l’observation en microscopie électronique simple (TEM) et sur cryofracture (FF‐SEM), d’un colorimètre et de l’analyse de la taille des particules. Le diamètre moyen des particules dispersées contenant l’astaxanthine allait de 160 à 190 nm. La distribution était unimodale et s’étendait de 100 à 200 nm. Les nano émulsions formulées avec les glyceryl esters (glyceryl citrate/ lactate / linoléate / oléate) donnaient des particules plus petites et une distribution de taille plus étroite que celles préparées avec la lécithine hydrogénée. La stabilité d’incorporation de l’astaxanthine dans les nano émulsions a été vérifiée et prouvée par HPLC, FF‐SEM et TEM. Les nano émulsions sont restées stables lors du stockage d’un mois en condition de lumière et de température en montrant un potentiel zêta inférieur à−41 mV preuve d’un système colloïdal stable.