title: Physicochemical characterization and in vitro release studies of ascorbyl palmitate-loaded semi-solid nanostructured lipid carriers (NLC gels).
abstract: The aim of this study was to characterize the physicochemical properties and to study in vitro release of ascorbyl palmitate from semi-solid lipid nanoparticles based on nanostructured lipid carriers (NLC gels) systems with the desired viscosity for dermal delivery. NLC gels were obtained by a one-step production procedure employing a high pressure homogenization technique using different solid lipid matrices. Ascorbyl palmitate (AP) was selected as a lipophilic active ingredient due to its range of cosmetic applications. After the production, particles within the size range 170-250 nm having polydispersity index lower than 0.3 were obtained from all formulations. After the AP incorporation into the NLC gels, the zeta potential increased to values higher than |30 mV|. Almost 100% encapsulation efficiency was observed. The obtained SEM and AFM data revealed non-spherical shaped nanoparticles. From DSC and X-ray diffraction studies, it was shown that the lipid recrystallized in the solid state possessing a less ordered structure as compared to the bulk material. The release study of active-loaded NLC gel formulations using Franz diffusion cells revealed that the type of lipid matrix affects both the rate and the release pattern. The viscoelastic measurements revealed a more elastic than viscous behaviour of NLC formulations indicating a typical gel-like structure.
authors.affiliation: Faculty of Pharmacy, Department of Pharmacy, Mahidol University, Sri-Ayutthaya Road, Rajathavee, Bangkok, Thailand.
authors.forename: Veerawat
authors.initials: V
authors.lastname: Teeranachaideekul
authors.forename: Eliana B
authors.initials: EB
authors.lastname: Souto
authors.forename: Rainer H
authors.initials: RH
authors.lastname: Müller
authors.forename: Varaporn B
authors.initials: VB
authors.lastname: Junyaprasert
mesh_terms: D001205:Ascorbic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D004337:Drug Carriers; D004548:Elasticity; D005782:Gels; D008055:Lipids / Q000008:administration & dosage / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D049329:Nanostructures / Q000737:chemistry*; D012995:Solubility; D013818:Thermogravimetry; D014783:Viscosity; D014961:X-Ray Diffraction
chemical_list: D004337:Drug Carriers; D005782:Gels; D008055:Lipids; D001205:Ascorbic Acid; C031226:6-O-palmitoylascorbic acid