Search results for "emulsion"

TiO2 nanocrystalline powders by W/O microemulsion synthesis

2012

PHEA-graft-polybutylmethacrylate copolymer microparticles for delivery of hydrophobic drugs.

2012

Abstract Polymeric microparticles encapsulating two model hydrophobic drugs, beclomethasone dipropionate (BDP) and flutamide (FLU) were prepared by using the high pressure homogenization-solvent evaporation method starting from a oil-in-water emulsion. For the preparation of polymeric microparticles a α,β-poly(N-2-hydroxyethyl)- d , l -aspartamide (PHEA) graft copolymer with comb like structure was properly synthesized via grafting from atom transfer radical polymerization (ATRP) technique, by using two subsequent synthetic steps. In the first step a polymeric multifunctional macroinitiator was obtained by the conjugation of a proper number of 2-bromoisobutyryl bromide (BIB) residues to the…

Prostaglandin E(2)-loaded microspheres as strategy to inhibit phagocytosis and modulate inflammatory mediators release.

2008

PGE(2), an arachidonic acid metabolite produced by various type of cells regulates a broad range of physiological activities in the endocrine, cardiovascular, gastrointestinal, and immune systems, and is involved in maintaining the local homeostasis. In the immune system, PGE(2) is mainly produced by APCs and it can suppress the Th1-mediated immune responses. The aim of this study was to develop PGE(2)-loaded biodegradable MS that prolong and sustain the in vivo release of this mediator. An o/w emulsion solvent extraction-evaporation method was chosen to prepare the MS. We determined their diameters, evaluated the in vitro release of PGE(2), using enzyme immunoassay and MS uptake by periton…

Development of accurate mass spectrometric routine and reference methods for the determination of trace amounts of iridium and rhodium in photographi…

1999

For the determination of trace amounts of iridium and rhodium in photographic emulsions different sample treatment procedures were coupled with inductively coupled plasma mass spectrometry (ICP-MS) and, for iridium, also with negative thermal ionisation isotope dilution mass spectrometry (NTI-IDMS) and ICP-IDMS. IDMS determinations of iridium were carried out using an enriched 191Ir spike solution. Elimination of the silver matrix was established for both mass spectrometric methods, which prevents corresponding memory effects in the ICP-MS system and is essential for the formation of IrO2 - thermal ions, respectively. For NTI-MS measurements, the gelatine matrix of the emulsion must also be…

Caffeic acid skin absorption: Delivery of microparticles to hair follicles

2019

Graphical abstract: Emulsions containing CA were prepared, one of which contain free CA and the other microencapsulated CA. They were applied to delimited area of skin. Subsequently the tape stripping and differential striping methods were applied.

Acid Catalysis with Alkane/Water Microdroplets in Ionic Liquids

2021

Ionic liquids are composed of an organic cation and a highly delocalized perfluorinated anion, which remain tight to each other and neutral across the extended liquid framework. Here we show that n-alkanes in millimolar amounts enable a sufficient ion charge separation to release the innate acidity of the ionic liquid and catalyze the industrially relevant alkylation of phenol, after generating homogeneous, self-stabilized, and surfactant-free microdroplets (1–5 μm). This extremely mild and simple protocol circumvents any external additive or potential ionic liquid degradation and can be extended to water, which spontaneously generates microdroplets (ca. 3 μm) and catalyzes Brönsted rather …

Emulsions based on fatty acid from vegetable oils for cosmetics

2022

Vegetable oils are sources of saturated, monounsaturated and polyunsaturated fatty acids. In this work, we studied the suitability of a mixture of vegetable oils and some fatty acids (similar to the those of the human skin) as a cosmetic emulsion. Hypericum (Hypericum perforatum L.) – 1 %, thistle (Silybum marianum (L.) Gaertn.) – 42 %, linen (Línum usitatíssimum L.) – 1.1 %, wheat germ (Triticum aestivum L.) – 1 %, sesame (Sésamum índicum L.) – 1 %, mustard (Sinápis álba L.) – 2%, pumpkin (Cucúrbita p é po L.) – 5 %, – were selected as vegetable oils. The emulsion based on the proposed mixture of vegetable oils has a higher antioxidant activity (1.623 OD) compared with that based on minera…

Physico-chemical properties of dense water/copper(II) bis(2-ethylhexyl) sulfosuccinate/CCl4 microemulsions

2007

Measurements of some physico-chemical properties (density, viscosity, conductance, infra-red spectra) of water/copper(II) bis(2-ethylhexyl) sulfosuccinate (Cu(DEHSS)2)/CCl4 microemulsions, as a function of the volume fraction O of the dispersed phase (0 < O < 0.6) and of the molar ratio R (R = [water]/[DEHSS−]), have been performed at 25 °C. At each value of R, the density of the micellar phase is practically independent of O whereas the viscosity of microemulsions diverges above threshold O values. A divergent behavior for the electrical conductivity has also been observed but only at certain R values. These results, together with those from infra-red spectra, suggest that in percolated mi…

Hydroxypropyl Cellulose Films Filled with Halloysite Nanotubes/Wax Hybrid Microspheres

2021

The design of novel nanocomposite films based on hydroxypropyl cellulose (HPC) and wax/halloysite hybrid microspheres has been reported. In particular, we first prepared wax/clay Pickering emulsions which were characterized by thermogravimetric analysis and microscopy. SEM images allowed more detailed insights on the nanotubes disposition at the wax/water interface, acting as an outer stabilizing shell. Therefore, the cellulosic biopolymer was added, and it was found that HPC enhances the colloidal stability of the particles, preventing their coalescence and sedimentation. The preparation of the composite films was carried out by the solvent casting method, which enabled the development of …

Transfer of aroma compounds in water-lipid systems: binding tendency of beta-lactoglobulin.

1998

Interactions of volatile aroma compounds with protein in aqueous solutions, especially whey proteins, have received significant attention in recent years. This work attempts to improve our understanding of the mass transfer in multiphasic systems, such as emulsions at the lipid−water interface, and to reveal the role of β-lactoglobulin in the release rate of solutes. For this purpose the rotating diffusion cell has been used. From a practical point of view it enables evaluation of the transfer through the aqueous phase, through the oil and the interfacial transfer. The effect of β-lactoglobulin, medium pH, and solute concentration has been investigated. Benzaldehyde and 2-nonanone have been…