Search results for "Swell"
showing 10 items of 215 documents
Novel inulin-based mucoadhesive micelles loaded with corticosteroids as potential transcorneal permeation enhancers
2017
In this work a new copolymer of inulin (INU) derivatized with ethylendiamine (EDA) and retinoic acid (RA), named INU-EDA-RA, was synthetized, characterized and employed to produce micelles as carriers for topical administration of corticosteroids for the potential treatment of diseases of posterior eye segment. Spectroscopic analysis confirmed a molar derivatization degree of 11.30 and 4.30% in EDA and RA, respectively. INU-EDA-RA micelles are capable of strong mucoadhesive interactions which result time-independent and stable over time but concentration depending. Moreover micelles are able to encapsulate efficiently from 3 to 13% (w/w) of lipophilic drugs, as dexamethasone, triamcinolone …
In vitro study of N-succinyl chitosan for targeted delivery of 5-aminosalicylic acid to colon
2011
In vitro study on N-succinyl chitosan and chitosan (control) matrices for selective colon delivery of 5-aminosalicylic acid is described. Matrices containing β-cyclodextrin were also prepared. As shown by DSC analyses, the drug was successfully loaded into the matrices reaching up to 95% entrapment efficiency. Swelling and drug release were studied at pH 1.2, pH 7.4, and in a pH gradient medium to simulate the gastro-intestinal transit. Main result of this study was a higher capability of N-succinyl chitosan alone to better control drug release in the simulated gastro-intestinal transit: N-succinyl chitosan gave the lowest release in acid medium (≅15%) and the highest in alkaline environmen…
Do female leaf beetles Galerucella nymphaeae choose their mates and does it matter?
1998
The role of active female choice in sexual selection is frequently difficult to ascertain, and this is particularly the case for many insect species. Also, it is uncertain whether choosing between males would affect offspring viability. We designed an experiment to investigate the presence of female choice in a Coleoptera species (Galerucella nymphaeae). We also estimated whether mate choice would have any effect on offspring performance. Females were first placed with two males in a test arena to see which of the males copulated with the virgin female, and how quickly. Subsequently the loser male was offered a new virgin female to test for any change in latency time until mating. The two-m…
A comprehensive experimental study of the rheological behaviour of HDPE.
1986
Extensional properties of four high density polyethylenes with different molecular weights and molecular weight distributions are presented. The samples have already been well characterized in shear and non-isothermal extensional flow. The data were collected at 180 °C for elongational rates between 3 · 10−1 and 10−4s−1. Some qualitative and quantitative generalizations of the results are given.
Sorption Equilibria of Ethanol on Cork
2013
International audience; We report here for the first time a thermodynamic study of gaseous ethanol sorption on raw cork powder and plate. Our study aims at a better understanding of the reactivity of this material when used as a stopper under enological conditions, thus in close contact with a hydroethanolic solution, wine. Sorption−desorption isotherms were accurately measured by thermogravimetry at 298 K in a large range of relative pressures. Sorption enthalpies were determined by calorimetry as a function of loading. Sorption−desorption isotherms exhibit a hysteresis loop probably due to the swelling of the material and the absorption of ethanol. Surprisingly, the sorption enthalpy of e…
Equilibrium swelling properties of polyampholytic hydrogels
1996
The role of counter ions and ion dissociation in establishing the equilibrium swelling of balanced and unbalanced polyampholytic hydrogels has been investigated experimentally and theoretically. The swelling dependence on both the net charge offset and the external bath salt concentration has been examined using an acrylamide based polyampholytic hydrogels. By careful consideration of the swelling kinetics, we illustrate the effects of ion dissociation equilibria and counter ion shielding in polyampholytic hydrogels near their balance point where both polyelectrolyte and polyampholyte effects are present. The theory considers a Flory type swelling model where the Coulombic interactions betw…
Swellable microparticles containing Suprofen: evaluation of in vitro release and photochemical behaviour
1998
Suprofen, an anti-inflammatory drug was incorporated in polymer networks based on biocompatible macromolecules, such as alpha,beta-polyasparthydrazide (PAHy) and alpha,beta-poly(N-hydroxyethyl)-DL-aspartamide (PHEA) crosslinked by glutaraldehyde or gamma-rays, respectively. Swelling tests carried out in aqueous media showed that pH value affects the swelling degree of the prepared hydrogels. In vitro release tests were performed in simulated gastrointestinal fluids (pH 1/6.8) using the pH variation method and in phosphate-buffered saline, pH 7.4. Experimental data indicated that Suprofen was released in a sustained way both from PAHy and PHEA microparticles. Further, incorporation of Suprof…
Foreign body granulomatous reactions to cosmetic fillers
2012
Introduction: The use of different facial cosmetic fillers has increased in recent years. The introduction of apparently inert substances in the epidermis can give rise to foreign body granulomatous reactions. Objetives: A literature review is made of the foreign body granulomatous reactions to cosmetic fillers. Material and Methods: A PubMed-Medline search was made using the following keywords: “granulomatous reactions”, “foreign body reactions”, “esthetic fillers”, “cosmetic fillers”. The search was limited to articles published in English and Spanish during the last 10 years. A total of 22 articles were reviewed. Results: A great variety of substances have been found to give rise to fore…
Oral manifestations of gastrointestinal disorders
2017
Indexación: Scopus. Backgroud: A considerable number of gastrointestinal disorders (GIDs) of varied nature (inflammatory, infectious, genetic and other etiology) may produce alterations in the hard and soft oral tissues. Among these are Crohn's disease, ulcerative colitis, celiac and gastroesophageal reflux disease. Material and Methods: Article search was done using the National library of medicine (PubMed) database using different search terms and analyzed according to their importance. Results: A large variety of GIDs can give rise to oral lesions, including: RAS like ulceration, mucosal tags, cobblestoning, mucogingivitis, labial and facial swelling, pyostomatitis vegetans, disgeusia an…
Dual Stimuli-Responsive Polysaccharide Hydrogels Manufactured by Radiation Technique
2022
Featured Application Stimuli-responsive hydrogels encompassing biobased polymers are anticipated for utilization in various fields, starting from drug delivery systems through temporal actuators and water reservoirs to biodegradable microelements and nutrient delivery depots. This paper describes the results of the radiation-induced crosslinking of polysaccharides modified with hydroxypropyl and carboxymethyl functional groups, hydroxypropylcellulose (HPC) and carboxymethylcellulose (CMC), respectively, without and with poly(ethylene glycol) diacrylate (PEGDA) as a crosslinking agent, to obtain dual stimuli-responsive hydrogels. The gels were characterized in terms of water uptake and gel f…