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Cotton gauze was inserted into a hydrogel network composed of acrylamide, sodium methacrylate, and polyethylene glycol dimethacrylate to fabricate an electroresponsive delivery system for wound dressing. The composite was characterized by swelling measurements, showing that shrinking or swelling depend on the applied voltage. The release profile of incorporated diclofenac sodium salt shows the possibility to modulate the kinetics by changes in the amplitude and duration of applied electric pulses. Mathematical models allow a characterization of release profiles, which are slower when an external voltage of 6, 12, and 18 V is applied, and faster at 24 V. [ABSTRACT FROM AUTHOR]

The present article reports the preparation, characterization and performance evaluation of solid lipid nanoparticles (SLNs) based on polyoxyethylene-40 stearate (PEG-40 stearate) for the administration of antifungal agents such as ketoconazole and clotrimazole. These nanoparticles could be useful in the treatment of vaginal infections sustained byCandida albicans. In particular, PEG-40 stearate was made to react with acryloyl chloride in order to introduce an easily polymerizable moiety for the creation of a second shell and to ensure a slow drug release. In addition, the differences on the release profiles between PEG-40 stearate-based nanoparticles, PEG-40 stearate acrylate based and polymerized ones, were analyzed under conditions, simulating the typical environment ofCandida albicansinfection. Then, the antifungal activity of nanoparticles was also evaluated in terms of minimal inhibitory concentration. Moreover, the nanoparticles were submitted toin vitrostudies for evaluating the drug permeability at the site of action. Results indicated that the obtained particles are potentially useful for the treatment of vaginal infections sustained byCandida albicans. [ABSTRACT FROM AUTHOR]

In recent years, antioxidants have gained great importance because of their potential use in food, pharmaceutical, and cosmetic industries. This interest is rooted in the cumulative evidence connecting active oxygen and free radicals with numerous human degenerative disorders, such as cardiovascular diseases, cancer, aging, and atherosclerosis. Polyphenols are the major class of antioxidant able to reduce the oxidative damages of lipids, proteins, enzymes, carbohydrates, and DNA in living cells and tissues. Among the realm of polyphenol compounds, polyphenol conjugates have been proposed as innovative materials which, by combining the advantageous properties of both the components, can increase the efficiency of antioxidants and their range of application in nutritional and biomedical fields. This work is an overview of the different class of polyphenol conjugates, which will be analyzed in terms of nutritional and biological properties, showing how these bio-conjugates will positively affect the human health. [ABSTRACT FROM AUTHOR]

Biodegradable casein nanospheres for the sustained release of bioactive molecules in the gastro-intestinal tract were prepared by precipitation polymerization using sodium methacrylate (NaMA) and N,N′-methylene bis-acrylamide (MEBA) as pH-responsive monomer and cross-linker. Three materials with different casein amount were obtained and characterized by scanning electron microscopy, dimensional analysis, water uptake, cytotoxicity and enzymatic degradation experiments. Nanospheres biodegradability was tuned by coating with polyacrylic acid. Coated and uncoated materials were investigated as delivery vehicles for diclofenac sodium salt. For un-coated samples, the release raise 100% in 30 h, while for coated specimens these values were lower than 70%, due to the diffusional constraints of polymer layer. [ABSTRACT FROM AUTHOR]

Cocoa contains many compounds such as biogenic amines (BAs), known to influence consumer health. Spermidine, spermidine, putrescine, histamine, tyramine, β-phenylethylamine, cadaverine and serotonine have been found in several cocoa-based products using HPLC with UV detection after derivatisation with dansyl-chloride. Once optimised in terms of linearity, percentage recovery, LOD, LOQ and repeatability, this method was applied to real samples. Total concentrations of BAs ranged from 5.7 to 79.0 µg g−1with wide variations depending on the type of sample. BAs present in all samples were in decreasing order: histamine (1.9–38.1 µg g−1) and tyramine (1.7–31.7 µg g−1), while putrescine (0.9–32.7 µg g−1), spermidine (1.0–9.7 µg g−1) and spermidine (0.6–9.3 µg g−1) were present in most of the samples. Cadaverine, serotonine and β-phenylethylamine were present in a few samples at much lower concentrations. Organic samples always contained much lower levels of BAs than their conventional counterparts and, generally speaking, the highest amounts of BAs were found in the most processed products. [ABSTRACT FROM PUBLISHER]

With the aim to modulate the flavonoid antioxidant properties, catechin and quercetin were covalently inserted into hydrogel networks by free radical grafting procedure. The effective conjugation of both flavonoids into the polymer chains was checked by FT-IR analyses. Water uptake measurements and calorimetric analyses proved the pH- and thermo-responsiveness. The effect of temperature on antioxidant properties were evaluated as scavenging ability and redox performance, while the determination of the ability to preserve folic acid from UV degradation proved the pH responsiveness. Data show that the matrices are more effective in the swollen than in the shrunken state. [ABSTRACT FROM PUBLISHER]

In this study, pH-responsive hydrogels, synthesized by the coupling reaction of polyacrylic acid and catechin, are proposed as carriers of oxidable drugs toward the GI tract. The presence of polyphenolic moieties in the network gives the polymers properties suitable for the release of unstable drugs in oxidative conditions. The characterization of the hydrogels is obtained by means of morphological and physico-chemical analyses, antioxidant assays and evaluation of the swelling behavior in media simulating the gastric (pH 1.0) and the intestinal (pH 7.4) tracts. The hydrogels are tested as pH-responsive carriers in in vitro release studies of folic acid and thiamine, two model drugs easily degraded by oxidative conditions simulated by UV irradiation and t-butyl hydroperoxide treatment, respectively. Results show that catechin-based carriers are able to control the release of drugs at different pH values, giving a remarkable improvement in the stability of the therapeutics. [ABSTRACT FROM AUTHOR]

Hybrid materials with enhanced antibacterial activity were prepared by incorporation of carbon nanotubes within gelatin-fluoroquinolones bioconjugates. Gelatin bioconjugates were characterized by UV-Vis, FT-IR, and calorimetric analyses, nanohybrids by morphological analyses. Biocompatibility was evaluated on human mesenchymal stem cells, and antibacterial performance againstKlebsiella pneumoniaeandEscherichia coli. Minimun inhibitory concentrations from 0.025 to 0.05 µg mL−1and from 0.025 to 0.10 µg mL−1, and MBC from 0.025 to 0.10 µg mL−1and from 0.05 to 0.20 µg mL−1were detected forEscherichia coliandKlebsiella pneumoniae, respectively, showing that nanotubes increase antimicrobial activity comparing to both free and gelatin-conjugated drugs. [ABSTRACT FROM AUTHOR]

Thermo-responsive polysaccharidic hydrogels were designed and synthesized by a free radical induced grafting procedure. Chitosan was chosen as biopolymer to impart biocompatibility and biodegradability to the macromolecular systems, while N-isopropylacrylamide (NIPAAm) was selected as co-monomer responsive for the thermo-sensitive properties. Ammonium persulfate was the initiator system and different polymeric networks have been synthesized by modulating the amount of NIPAAm in the polymerization feed. The resulting hydrogels were proposed as drug delivery devices and their performance was evaluated by using Diclofenac sodium salt as a model drug. Hydrogels were carefully characterized by FT-IR spectrophotometry, calorimetric analyses and swelling behavior in a temperature range of 15-45°C. Finally, to verify the suitability of these hydrogels as thermo-responsive devices, the drug release profiles were studied performing in vitro experiments around the swelling-shrinking transition temperatures of the macromolecular systems. [ABSTRACT FROM AUTHOR]

Context: Flavonoids preservation and release. Objective: Synthesis of a polymeric material able to prevent thermal and photo degradation of a flavonoid model compound, such as (+)-catechin, and suitable for a controlled/sustained delivery of this molecule in gastro-intestinal simulating fluids. Materials and methods: Methacrylic acid (MAA) was grafted onto poly( N-vinyl-pyrrolidone) (PVP) by a free radical grafting procedure involving a single-step reaction at room temperature. For this purpose, hydrogen peroxide/ascorbic acid redox pair was employed as water-soluble and biocompatible initiator system. Results and discussion: FT-IR spectra confirmed the insertion of MAA onto the polymeric chain. Stability studies, performed under various conditions, such as freeze-thaw cycles, exposure to strong light, thermal stability studies under constant humidity and with light protection at different temperatures, showed the preservative properties of the polymeric material towards flavonoids. Furthermore, the biocompatibility was highlighted by Hen's Egg Test-Chorioallantoic Membrane assay and in vitro release studies demonstrated the possibility to employ PVP-MAA copolymer as a device for gastro-intestinal release of flavonoids. Conclusion: The coupling of good preservative properties together with biocompatibility and the usefulness as carrier in controlled release make this kind of material very interesting from an industrial point of view for different applications in food, pharmaceutical, and cosmetic fields. [ABSTRACT FROM AUTHOR]

A novel flavonoid-polysaccharide conjugate was synthesized by free radical grafting of quercetin on starch. The covalent insertion of quercetin in the polymeric chain was confirmed by FT-IR, DSC and fluorescence analyses, while an estimation of the amount of quercetin bound per g of polymer was obtained by the Folin-Ciocalteu assay. The conjugate shows improved UV stability and retains the antioxidant properties of free quercetin, such as scavenging activity towards free radicals (DPPH and peroxynitrite); inhibition of the free radical formation (peroxidation of linoleic acid) and total antioxidant activity. The conjugate also prevented drug degradation and shows potential health functionality in the treatment of Alzheimer disease, diabetes and as skin-whitening agent. [ABSTRACT FROM AUTHOR]

Phospholipids (PLs), the most important class of polar lipids in foods, are ubiquitous compounds because they are the major components of animal and plant cell membranes. Their technological and biological properties therefore make them important in human nutrition. The efficient separation and accurate quantification of PLs can be achieved with high-performance liquid chromatography–evaporative light scattering detection (HPLC-ELSD) because ELSD is a quasi-universal detector for liquid, countercurrent, and supercritical fluid chromatography and can detect any analyte less volatile than the mobile phase. In this article, the principles of ELSD operation (i.e., nebulization of the chromatographic effluent, evaporation of the mobile phase, and measurement of the scattered light) as well as the application of LC-ELSD to determine the amount of PLs in different food matrices are reviewed. Food matrices containing PLs include milk and dairy products, meat, fish, eggs, cereals, and oils. Both the technological aspects and analytical parameters affecting the concentration and quantitative determination of PLs in food matrices are evaluated. In particular, different extraction, purification, and chromatographic conditions were extensively investigated; moreover, wherever possible, the results obtained are reported and compared with other detection methods. [ABSTRACT FROM PUBLISHER]

Thermal and dual stimuli-responsive microspheres (pH and temperature) were prepared by free radical polymerization of methacrylate bovine serum albumin (BSA-MA) as cross-linker and sodium methacrylate (NaMA) and/or N-isopropylacrylamide (NIPAAm), as hydrophilic/pH-sensitive and thermo-responsive monomers, respectively. Microgels were characterized by infrared spectroscopy, morphological analysis, particle size distribution and determination of swelling properties. The network density and the shape of the microgels were found to depend on the concentration of the reactive species in the polymerization feed. Thermal analyses were performed to determine lower critical solution temperature values, which become close to the body temperature by increasing the content of the hydrophilic moieties in the network. In order to test the preformed materials as drug carriers, in vitro release studies of Diclofenac diethyl ammonium salt were performed. For all the co-polymers, a predominant drug release in the collapsed state was observed, while below the microgel transition temperature, a drug release through the swollen network occurs. The data recorded during the release tests demonstrated that the pH of the surrounding environment influences the drug release more than the temperature of the imbibing medium. [ABSTRACT FROM AUTHOR]

In this work, the possibility to employ molecularly imprinted polymers as base excipients for controlled drug delivery devices was demonstrated. As template molecule, our attention was focused on phytic acid, a water soluble antioxidant compound. The possibility to raise a controlled/sustained release of an antioxidant agent is very useful from an application point of view; in recent years, indeed, biomedical applications of antioxidants have greatly grown because the link between human diseases and oxidative stress were proved. Polymers were synthesized using methacrylic acid as functional monomer and N,N′-Ethylenebis(acrylamide) as crosslinker. After the evaluation of the imprinting efficiency of the synthesized materials by binding experiments in which the percentage of phytic acid bounded by the molecularly imprinted polymers was found to be remarkably higher compared to the non-imprinted ones, MIP were tested as a controlled release device for the antioxidant in gastrointestinal simulating fluids. [ABSTRACT FROM AUTHOR]

In this study, we report the results of our investigations on the percutaneous permeation profiles of Diclofenac sodium, Paracetamol, Propanolol hydrochloride, and α-Tocopherol from the different lyotropic liquid crystalline phases obtained by Pluronic P105/water mixtures, in order to understand if the particular assembly shown in the formulations could influence the delivery across the skin. Recent studies have focused on the Pluronic liquid crystalline phases to evaluate the potential use of these phases in drug delivery, but no comparative investigation has been yet performed on the drug permeation from the different liquid crystalline phases obtained by the same Pluronic surfactant. The cubic, hexagonal, and lamellar mesophases (loading the above-mentioned drug) were characterized by Deuterium Nuclear Magnetic Resonance spectroscopy and Polarized Optical Microscopy observations. Results revealed that the liquid crystalline gel microscopic structure obtained in the different formulations drastically affects the drug percutaneous availability. As a consequence these systems could be proposed as novel transdermal drug delivery systems. [ABSTRACT FROM AUTHOR]

Biomedical applications of antioxidants have increased dramatically since the link between human diseases and oxidative stress was established. This paper focuses on α -tocopherol and on the possibility of employing molecularly imprinted polymers as a controlled release device for α -tocopherol in gastrointestinal simulating fluids. Polymers were synthesized using methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross-linker. Considerable differences in recognition characteristics between imprinted and non-imprinted polymers, both in organic and in aqueous media, were observed. Imprinted polymers bound much more α -tocopherol and showed a controlled/sustained drug release capacity in gastrointestinal simulating fluids. [ABSTRACT FROM AUTHOR]

The synthesis, characterisation, helical pitch and electro-optical response of new ferroelectric liquid crystals, 4'-(ω-acryloxyalkoxy)-, 4'-(ω-alkanoyloxyalkoxy)- or 4'-(ω-perfluoroalkanoyloxy)alkoxybiphenyl-4-yl (S)-4-(1-octyloxy)benzoates, bearing either polymerisable or non-polymerisable terminal groups, are described. The synthesised liquid crystals exhibit both a chiral smectic C phase and a chiral nematic phase. The helical pitch and electro-optical properties of the new compounds were determined as a function of temperature. [ABSTRACT FROM AUTHOR]

Antineoplastic methotrexate has been loaded through different soaking procedures on silica-based mesoporous materials and, successively, released mimicking an oral administration. The materials were prepared using a self-assembly mechanism in the presence of cationic surfactants with alkyl chain of 16, 12, and 10 carbon atoms in the synthesis mixture to obtain different pore diameter in the porous structure. Mesoporous materials were prepared as pure silica sample and in the presence of Al(OH)3 in the synthesis mixture. Only alumina-silica samples were able to load methotrexate. The amounts of drug loaded and the in vitro release kinetics are a function of the pore size of the materials. [ABSTRACT FROM AUTHOR]

Reverse-mode operation films can be achieved with polymer dispersed liquid crystals by many methods. One method consists in the use of either rough or polyimide treated supports in order to induce homeotropic alignment of the initial mixture that will separate in liquid crystal and polymer rich phases. The major disadvantage is the need for mesogenic monomers to keep a good alignment of the liquid crystal after the polymerization process. In this paper we present results concerning the use of an anisometric, non-mesogenic, tailor-made monomer for the preparation of excellent reverse-mode polymer dispersed liquid crystal shutters cast on rough surfaces. The combined use of rough surfaces and non-mesogenic monomers allows us to exceed earlier limits in physical and chemical properties, cost, and device dimensions by the use of a wider class of monomer molecules. [ABSTRACT FROM AUTHOR]