Search results for "carrier"

PHEA-PLA biocompatible nanoparticles by technique of solvent evaporation from multiple emulsions

2015

Nanocarriers of amphiphilic polymeric materials represent versatile delivery systems for poorly water soluble drugs. In this work the technique of solvent evaporation from multiple emulsions was applied to produce nanovectors based on new amphiphilic copolymer, the α,β-poly(N-2-hydroxyethyl)-DL-aspartamide-polylactic acid (PHEA-PLA), purposely synthesized to be used in the controlled release of active molecules poorly soluble in water. To this aim an amphiphilic derivative of PHEA, a hydrophilic polymer, was synthesized by derivatization of the polymeric backbone with hydrophobic grafts of polylactic acid (PLA). The achieved copolymer was thus used to produce nanoparticles loaded with α toc…

Buccal drug delivery: what's new and what does the future hold?

2014

The buccal mucosa is the stratified squamous epithelial tissue inside lining of the cheeks. It is a favorable site of drug absorption since the tissue is non-keratinized, relatively immobile and strongly supplied with blood by a dense capillary-vessel network; moreover, it is highly tolerant to allergens, resistant to potentially harmful agents and has a relatively low enzymatic activity. The tissue consents quick onset of effect, offers an easily accessible and generally well-accepted site for drug delivery, is a useful route of administration in patients in an unconscious state (e.g., when swallowing is impaired), and is suitable for retentive dosage forms of administration. Buccal mucosa…

COMBINATION OF ARGAN OIL AND PHOSPHOLIPIDS FOR THE DEVELOPMENT OF AN EFFECTIVE LIPOSOME-LIKE FORMULATION ABLE TO IMPROVE SKIN HYDRATION AND ALLANTOIN…

2016

Allantoin is traditionally employed in the treatment of skin ulcers and hypertrophic scars. In the present work, to improve its local deposition in the skin and deeper tissues, allantoin was incorporated in conventional liposomes and in new argan oil enriched liposomes. In both cases, obtained vesicles were unilamellar, as confirmed by cryo-TEM observation, but the addition of argan oil allowed a slight increase of the mean diameter (∼130nm versus ∼85nm). The formulations, especially those containing argan oil, favoured the allantoin accumulation in the skin, in particular in the dermis (∼8.7μg/cm(2)), and its permeation through the skin (∼33μg/cm(2)). The performances of vesicles as skin d…

Gold nanostar–polymer hybrids for siRNA delivery: Polymer design towards colloidal stability and in vitro studies on breast cancer cells

2017

To overcome the low bioavailability of siRNA (small interfering RNA) and to improve their transfection efficiency, the use of non-viral delivery carriers is today a feasible approach to transform the discovery of these incredibly potent and versatile drugs into clinical practice. Polymer-modified gold nanoconstructs (AuNCs) are currently viewed as efficient and safe intracellular delivery carriers for siRNA, as they have the possibility to conjugate the ability to stably entrap and deliver siRNAs inside cells with the advantages of gold nanoparticles, which can act as theranostic agents and radiotherapy enhancers through laser-induced hyperthermia. In this study, AuNCs were prepared by coat…

9-cis-Retinoic acid enhances fatty acid-induced expression of the liver fatty acid-binding protein gene

1997

The role of retinoic acids (RA) on liver fatty acid- binding protein (L-FABP) expression was investigated in the well differentiated FAO rat hepatoma cell line. 9-cis-Retinoic acid (9-ci's-RA) specifically enhanced L-FABP mRNA levels in a time- and dose-dependent manner. The higher induction was found 6 h after addition of 10 -6 M 9-CK-RA in the medium. RA also enhanced further both L-FABP mRNA levels and cytosolic L-FABP protein content induced by oleic acid. The retinoid X receptor (RXR) and the peroxisome proliferator-activated receptor (PPAR), which are known to be activated, respectively, by 9-c/s-RA and long chain fatty acid (LCFA), co-operated to bind specifically the peroxisome prol…

VALUTAZIONE DELL' EFFICACIA DI DERIVATI ANFIFILICI DEL PEG COME " SURFACE MODIFIERS" DI NANOCARRIER DI FARMACI

2011

Light-induced transmission nonlinearities in gallium selenide

1999

The intensity of a He–Ne laser (633 nm, 5 mW) transmitted by different GaSe samples is observed to change in correlation with a Nd-yttrium–aluminum–garnet laser pulse (532 nm, 7.8 ns, 3 mJ) which excites them. Such time response has been attributed to a nonlinear optical effect, i.e., a decrease in the refractive index due to the exciton screening by the photogenerated carriers. A calculation of the absorption coefficient and refractive index at different carrier concentrations has led to a reconstruction of transmittance transients which fully agree with the experimental data at different incident intensities and temperatures. Chantal.Ferrer@uv.es ; Jaqueline.Bouvier@uv.es ; Miguel.Andres@…

1H NMR methodologies applied in the thermodynamic and structural characterization of organic supramolecular complexes

2021

Orientador: Anita Jocelyne Marsaioli Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química Resumo: Nesta tese consiste no estudo de interações supramoleculares utilizando diferentes metodologias de Ressonância Magnética Nuclear de hidrogênio (RMN de 1H), tais como ROESY 1D, RMN-DOSY e RMN-STD. Os sistemas supramoleculares foram abordados em dois casos de estudo diferentes. O Capítulo I tem como objeto de estudo interações do fármaco Dapsona com diferentes carreadores de fármacos (ß-CD, SBE-ß-CD e lipossoma de EPC), com a finalidade de encontrar formulações nas quais a Dapsona seja mais solúvel. Os complexos binários e ternário formados foram determinadas por medidas de …

Different pathways for the nuclear import of yeast RNA polymerase II

2015

Recent studies suggest that RNA polymerase II (Pol II) has to be fully assembled before being imported into the nucleus, while other reports indicate a distinct mechanism to import large and small subunits. In yeast, Iwr1 binds to the holoenzyme assembled in the cytoplasm and directs its nuclear entry. However, as IWR1 is not an essential gene, Iwr1-independent pathway(s) for the nuclear import of Pol II must exist. In this paper, we investigate the transport into the nucleus of several large and small Pol II subunits in the mutants of genes involved in Pol II biogenesis. We also analyse subcellular localization in the presence of drugs that can potentially affect Pol II nuclear import. Our…

Trehalose-hydroxyethylcellulose microspheres containing vancomycin for topical drug delivery.

2001

Abstract A new formulation, in which vancomycin is entrapped into trehalose and hydroxyethylcellulose (Natrosol ® ) spherical matrices, is described. Microspheres were produced by the solvent evaporation method. The entrapped drug was fully recovered following microspheres dissolution. Differential scanning calorimetry analyses proved that Natrosol maintains trehalose in its amorphous form. The stabilizing effects of trehalose on vancomycin were evaluated even after long storage and heating of microspheres. Calorimetric data indicated no decomposition of the entrapped drug. In vitro drug release, already performed by using a general two-compartment linear time-invariant open model, suggests…