title: Physicochemical characteristics, cytotoxicity, and antioxidant activity of three lipid nanoparticulate formulations of alpha-lipoic acid.
abstract: Exogenously supplied alpha-lipoic acid (LA) has proven to be effective as an antioxidant. In an effort to develop a water-soluble formulation for topical administration, LA was formulated in the form of solid lipid nanoparticles (SLN), nanostructure lipid carriers (NLC), and nanoemulsion (NE) and characterized in terms of physical and biological properties. Mean particle size of 113, 110, and 121 nm were obtained for NE, NLC, and SLN, respectively, with narrow size distribution. Zeta potential was approximately in the range of -25 to -40 mV. Disc and spherical structures of nanoparticles were observed by cryo-scanning electron microscopy. Entrapment efficiency of LA in three formulations was found to be more than 70%. After 120 days of storage at 25 degrees C, physical stability of all formulations remained unchanged whereas the entrapment efficiency of SLN and NLC could be maintained, suggesting relative long-term stability. Prolonged release of LA formulation following the Higuchi model was found where a faster release was observed from NE compared with that of SLN and NLC. More than 80% of cell survivals were found up to 1 microM of LA concentrations. Antioxidant activity analysis demonstrated that all LA-loaded formulations expressed antioxidant activity at a similar magnitude as pure LA. These results suggest that chosen compositions of lipid nanoparticles play an important role on drug loading, stability, and biological activity of nanoparticles. Both SLN and NLC demonstrated their potential as alternative carriers for aqueous topical administration of LA.
authors.affiliation: National Nanotechnology Center, National Science and Technology Development Agency, 111 Thailand Science Park, Paholyothin Road., Klong 1, Klong Luang, Pathumthani, Thailand. uracha@nanotec.or.th
authors.forename: Uracha
authors.initials: U
authors.lastname: Ruktanonchai
authors.forename: Piyawan
authors.initials: P
authors.lastname: Bejrapha
authors.forename: Usawadee
authors.initials: U
authors.lastname: Sakulkhu
authors.forename: Praneet
authors.initials: P
authors.lastname: Opanasopit
authors.forename: Nuntavan
authors.initials: N
authors.lastname: Bunyapraphatsara
authors.forename: Varaporn
authors.initials: V
authors.lastname: Junyaprasert
authors.forename: Satit
authors.initials: S
authors.lastname: Puttipipatkhachorn
mesh_terms: D000287:Administration, Topical; D000975:Antioxidants / Q000008:administration & dosage / Q000737:chemistry* / Q000494:pharmacology / Q000633:toxicity; D002152:Calorimetry, Differential Scanning; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D004305:Dose-Response Relationship, Drug; D004337:Drug Carriers; D004339:Drug Compounding; D004355:Drug Stability; D004655:Emulsions; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D007700:Kinetics; D008055:Lipids / Q000737:chemistry*; D008956:Models, Chemical; D053758:Nanoparticles; D016877:Oxidants / Q000633:toxicity; D018384:Oxidative Stress / Q000187:drug effects; D010316:Particle Size; D012995:Solubility; D013499:Surface Properties; D013678:Technology, Pharmaceutical / Q000379:methods; D008063:Thioctic Acid / Q000008:administration & dosage / Q000737:chemistry* / Q000494:pharmacology / Q000633:toxicity
chemical_list: D000975:Antioxidants; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D004655:Emulsions; D008055:Lipids; D016877:Oxidants; D008063:Thioctic Acid; D006861:Hydrogen Peroxide