Formulation and Preliminary in vivo Testing of Rufloxacin-Cyclodextrin Ophthalmic Solutions

Aim of the present work was to investigate the effect of somecyclodextrins (CDs) on the solubility and ocular bioavailability of rufloxacin base (RUF), with theultimate goal of developing an ophthalmic formulation. Phase solubility studies of RUF inpH 7.4 buffer were carried out in the presence of -cyclodextrin (-CD),hydroxypropyl--cyclodextrin (HP--CD) and -cyclodextrin(-CD). The effect of hydroxypropyl methylcellulose (HPMC) on RUF solubility was evaluated after heating the solutionscontaining HP--CD at 120 °C.A significant enhancement of RUF solubility was achieved by associatingthe drug with CDs, particularly HP--CD. This CD formed with RUF a less stablecomplex than that formed by -CD, but did not suffer the solubility limitations ofthe parent CD, and showed a higher solubilizing capacity than -CD. Addition of 0.25%(w/v) HPMC to solutions containing HP--CD increased the solubilizing effect of this CD,thus allowing reduction of the amount necessary for solubilization of 0.3% (w/v) RUF.Preliminary pharmacokinetic data in rabbits indicated that theocular bioavailability of 0.3% (w/v) RUF solubilized by HP--CD was higher when compared witha 0.3% (w/v) RUF suspension used as reference.     

Tandem mass spectrometry in food safety assessment: the determination of phthalates in olive oil

A gas chromatography-tandem mass spectrometry (GC-MS/MS) method for the detection of six phthalates in olive oil was developed. A gel permeation chromatography (GPC) clean-up step with cyclohexane:dichoromethane 7:3 as mobile phase was employed to remove the high-molecular mass species present in oil. Two ionization methodologies, i.e. electron (EI) and isobutane-chemical ionization (CI), were compared, in MS/MS mode, to achieve better analytical performances. An overall evaluation of all analytical parameters shows that the EI-MS/MS approach provides satisfactory results and is to be preferred to CI-MS/MS, at least in the case of the examined analytes. The observed accuracies, ranging from 71.7% to 112.2%, and the RSD values less than 9.7%, confirm the effectiveness of the proposed method in the assay of phthalate content in such a complex matrix as olive oil. The proposed protocol for the identification and assay of phthalates in olive oil might be of interest for the implementation of the QS (quality assurance scheme) for residue monitoring in food safety assessment.     

Synthesis of DnaK and GroEL in Escherichia coli cells exposed to different magnetic field signals

The effects of extremely low frequency magnetic field (ELF-MF)(1 mT, 50 Hz) on the heat shock protein (HSP) synthesis in Escherichia coli were investigated. Two magnetic field signals were studied: sinusoidal (SMF) and pulsed square wave (PMF). It was found that bacteria exposed to SMF showed a significantly higher level of DnaK and GroEL proteins as compared to sham-exposed bacteria as revealed by Western blot, whereas a lower level was observed after PMF exposure. Similar results were obtained when bacterial cells were exposed to heat shock (HS) after ELF-MF exposure: again SMF and PMF resulted in an increase and in a reduction of HSP amount in comparison with sham control, respectively. In conclusion, the MF influences the synthesis of HSPs in E. coli in a way that critically depends on the signal characteristics.     

Polymerizable Ligands as Stabilizers for Nanoparticles

Monomers bearing functional groups that can get chemisorbed on nanoparticles to form polymerizable monolayers have emerged as an interesting class of stabilizer ligands for various nanoparticles. High‐surface coverage, their ability to modify the properties of underlying nanoparticles, capability to form polymers of different molecular weights and possibility to make structural modifications make them attractive for their use as stabilizer ligands for nanoparticles. Both in situ and post‐synthesis grafting methods for attaching polymerizable ligands to nanoparticles are frequently used. The advantage of grafting polymerizable stabilizer on the surface of nanoparticles is that initially the polymerizable molecule acts as a proper stabilizer for the nanoparticles and later their surface polymerization or co‐polymerization with another suitable monomer can be carried out to generate the desired polymer scaffold around the nanoparticles, which ensures the increased stability of the resulting core‐polymerized shell nanoparticles. This review discusses interesting reports from recent literature on grafting of polymerizable ligands and their polymerization on gold, silver, silica, and iron oxide nanoparticles.     

Proficiency testing as an instrument to assess the analytical performance and the methods routinely implemented: the Italian experience for the screening of antibiotic residues in milk in the official control

Accreditation and Quality Assurance - The present work describes the outcome of the second proficiency test (PT) for the routine screening of antibiotic residues in milk, organized in 2016, for the...     

Phytosterols in supplements containing Serenoa repens: an example of variability of active principles in commercial plant based products

Phytosterols are one of the bioactive components responsible for the beneficial effects of Serenoa repens in Benign Prostate Hyperplasia. The aim of this study was to verify the actual variability of the phytosterols content in supplements containing serenoa, in order to provide useful elements to check the effectiveness of these preparations. The amount of campesterol, stigmasterol and β-sitosterol were determined by gas-chromatography in commercial raw materials and supplements containing serenoa in association or not with other botanicals. The experimental data were used to calculate amounts of phytosterols for recommended daily dose. The overall results of this study show an extreme variability in the content and also in the amounts per daily dose of phytosterols of the examined supplements (both mono/multi components). These data confirm that the characterization of serenoa based supplements is insufficient to ensure comparable effects between different products.     

Complete polynomial vector fields on the complex plane

We give a full classification, up to polynomial automorphisms, of complete polynomial vector fields in two complex variables.     

Controlled post‐synthesis grafting of thermoresponsive poly(N‐isopropylacrylamide) on mesoporous silica nanoparticles

Ordered mesoporous silica nanoparticles with pore diameter of 5 nm were synthesized by modification of the sol‐gel synthesis method. Post‐synthesis two‐step grafting of thermoresponsive poly(N‐isopropylacrylamide) inside the mesopores of the nanoparticles was carried out by distillation–precipitation polymerization of the methacryloxy‐functionalized mesoporous nanoparticles with N‐isopropylacrylamide monomer. A precise control on the quantity of the grafted polymer was achieved by changing the ratio of monomer to methacryloxy‐functionalized nanoparticles. The polymer‐grafted hybrid nanoparticles obtained were fully characterized by infrared spectroscopy, X‐ray diffraction, dynamic light scattering, transmission electron microscopy, thermal, and gas‐volumetric analyses, which clearly showed presence and thermoresponsive behavior of the polymer inside the mesopores with the preservation of the characteristic mesoporous structure of the nanoparticles. Copyright © 2015 John Wiley & Sons, Ltd.     

Mesures harmoniques conformes et feuilletages du plan projectif complexe

Résumé. On introduit la notion de mesure harmonique conforme pour les feuilletages holomorphes des surfaces complexes. Dans le cas d'un feuilletage du plan projectif, de degré d, on démontre que l'exposant (ou dimension transverse) d'une telle mesure est majoré par .