Solid Core (solid + core)

Distribution by Scientific Domains


Selected Abstracts


Cosmetic features and applications of lipid nanoparticles (SLN®, NLC®)

INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 3 2008
E. B. Souto
Synopsis A detailed review of the literature is presented in attempts to emphasize several advantages of solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) for cosmetic applications. Examples of several actives are given and the main features of the solid core of SLN and NLC for topical delivery of cosmetics are discussed. Lipid nanoparticles have been more and more explored in pharmaceutical technology, showing superior advantages for topical purposes over conventional colloidal carriers. Résumé Un examen détaillé de la littérature est présenté dans les tentatives de souligner les plusieurs avantages des nanoparticule lipidique solide (SLN) et lipidique nanostructurés (NLC) pour applications cosmétiques. Exemples de plusieurs substances actives sont données et les caractéristiques principales du noyau plein de SLN et de NLC pour la libération topique des produits de beauté sont discutées. Les nanoparticles lipides ont été de plus en plus explorées en technologie pharmaceutique, montrant des avantages supérieurs pour les porteurs colloïdaux conventionnels pour administration topique de buts. [source]


Fabrication by three-phase emulsification of pellicular adsorbents customised for liquid fluidised bed adsorption of bioproducts

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 11 2003
Mohsen Jahanshahi
Abstract A novel dense pellicular adsorbent, custom-designed for liquid fluidised bed adsorption of protein bioproducts, has been fabricated by coating zirconia,silica particles with agarose gel in a three-phase emulsification process. A slurry feedstock comprising solid zirconia,silica particles (120 µm average diameter) suspended in an aqueous solution of agarose was emulsified in an oil,surfactant mixture in a stirred vessel to yield composite droplets. These were subsequently stabilised by cooling to form spherical pellicular particles characterised by a porous, pellicular coat cast upon a solid core. The impact of agitation speed, surfactant concentration, oil viscosity and slurry composition upon the pellicle depth and overall particle diameter was investigated. Pellicle depth decreased with increasing impeller speed and decreased oil viscosity, whilst increased slurry viscosity enhanced that parameter. Initial increases from low concentrations of Span 80 surfactant (0.1% w/v oil) reduced the depth of the agarose pellicle, but the highest values investigated (1.5% w/v oil) promoted particle aggregation. The fluidisation behaviour of particles fabricated under various conditions was characterised by the measurement of expansion coefficients and axial dispersion coefficients for the liquid phase when operated in a standard fluidised bed contactor. Both parameters were found to be comparable or superior to those reported for conventional, composite fluidised bed adsorbents. The controlled coating of porous agarose upon a solid core to yield specific pellicular geometries is discussed in the context of the fabrication of adsorbents customised for the recovery of a variety of bioproducts (macromolecules, nanoparticulates) from complex particulate feedstocks (whole broths, cell disruptates and unclarified bio-extracts). Given the agreement between the size of the pellicular particles and the trends expected from theory, the large-scale manufacture of such particles for customised industrial use is recommended. Copyright © 2003 Society of Chemical Industry [source]


Swelling and polymer erosion for poly(ethylene oxide) tablets of different molecular weights polydispersities

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 3 2010
Anna Körner
Abstract The aim of the study was to determine and compare the degree of swelling and the swelling kinetics of poly(ethylene oxide) (PEO) hydrophilic matrix tablets without any additives for matrixes with different molecular weight polydispersities. A wide range of "mixed" polydisperse PEO tablets were obtained by mixing two PEO batches with average molecular weights of 105 and 2,×,106, respectively. These were compared with "single-batch" tablets with narrower mono-modal molecular weight distributions. A texture analyzer (TA) was used to determine, during the entire dissolution process, the thickness of the "gel" layer, the height of the dry tablet core and the total height of the tablet. The release of polymer from the tablet was also measured using a chromatographic method. Both the swelling histories and the polymer release rates varied strongly with molecular weight and agitation rate, whereas the rate of dissolution of the solid core varied much less with molecular weight. For single-batch and mixed tablets, tuned to give the same release rate, the swelling process was found to be very similar, regardless of the molecular polydispersity (between 1.2 and 8.8). These results support a previously proposed dissolution model with the key assumption of a constant critical viscosity, independent of time or polymer molecular weight, at the surface of the gel layer of a dissolving tablet. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99: 1225,1238, 2010 [source]


Supramolecular Structures Generated by Spherical Polyelectrolyte Brushes and their Application in Catalysis

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 9-10 2009
Yan Lu
Abstract We survey recent studies on composite particles made from spherical polyelectrolyte brushes (SPB) and catalytically active nanoparticles or enzymes. SPB consist of a solid core (diameter: ca. 100 nm) onto which long chains of anionic or cationic polyelectrolyte (PE) are densely grafted ("PE brush"). Immersed in water the PE layer affixed to the colloidal core will swell due to the enormous osmotic pressure of the confined counterions ("osmotic brush"). This confinement of the counterions can be used to generate metal nanoparticles on the surface of the SPB. Moreover, enzymes can be immobilized within the PE layer. In both cases, the resulting composite particles are stable against coagulation and can be easily handled and filtered off. The catalytic activity of both systems is largely preserved in case of the enzymes, in case of the metal nanoparticles it is even enhanced. Thus, the SPB present an excellent carrier system for applications in catalysis. [source]