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Elisabetta Esposito,1 Elena Pozza,2 Catia Contado,1 Walter Pula,1 Olga Bortolini,3 Daniele Ragno,1 Sofia Toldo,3 Fabio Casciano,4 Agnese Bondi,1 Enrico Zauli,2 Paola Secchiero,4 Giorgio Zauli,3 Elisabetta Melloni4 1Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, Ferrara, I-44121, Italy; 2Department of Translational Medicine, University of Ferrara, Ferrara, I-44121, Italy; 3Department of Environmental Sciences and Prevention, University of Ferrara, Ferrara, I-44121, Italy; 4Department of Translational Medicine and LTTA Centre, University of Ferrara, Ferrara, I-44121, ItalyCorrespondence: Elisabetta Esposito; Elisabetta Melloni, Tel +39 0532 455230 ; +39 0532 455936, Email ese@unife.it; elisabetta.melloni@unife.itPurpose: Proliferative vitreoretinal diseases (PVDs) represent a heterogeneous group of pathologies characterized by the presence of retinal proliferative membranes, in whose development retinal pigment epithelium (RPE) is deeply involved. As the only effective treatment for PVDs at present is surgery, we aimed to investigate the potential therapeutic activity of Nutlin-3a, a small non-genotoxic inhibitor of the MDM2/p53 interaction, on ARPE-19 cell line and on human RPE primary cells, as in vitro models of RPE and, more importantly, to formulate and evaluate Nutlin-3a loaded liposomes designed for ophthalmic administration.Methods: Liposomes were produced using an innovative approach by a microfluidic device under selection of different conditions. Liposome size distribution was evaluated by photon correlation spectroscopy and centrifugal field flow fractionation, while the liposome structure was studied by transmission electron microscopy and Fourier-transform infrared spectroscopy. The Nutlin-3a entrapment capacity was evaluated by ultrafiltration and HPLC. Nutlin-3a biological effectiveness as a solution or loaded in liposomes was evaluated by viability, proliferation, apoptosis and migration assays and by morphological analysis.Results: The microfluidic formulative study enabled the selection of liposomes composed of phosphatidylcholine (PC) 5.4 or 8.2 mg/mL and 10% ethanol, characterized by roundish vesicular structures with 150– 250 nm mean diameters. Particularly, liposomes based on the lower PC concentration were characterized by higher stability. Nutlin-3a was effectively encapsulated in liposomes and was able to induce a significant reduction of viability and migration in RPE cell models.Conclusion: Our results lay the basis for a possible use of liposomes for the ocular delivery of Nutlin-3a. Keywords: Nutlin-3a, liposomes, microfluidic, PVDs, CFFF

Diesel particulate matter is one of the most dangerous environmental stressors affecting human health. Many plant-derived compounds with antioxidant and anti-inflammatory properties have been proposed to protect the skin from pollution damage. Curcumin (CUR) has a plethora of pharmacological activities, including anticancer, antimicrobial, anti-inflammatory and antioxidant. However, it has low bioavailability due to its difficult absorption and rapid metabolism and elimination. CUR encapsulation in nanotechnological systems and its combination with biopotentiators such as piperine (PIP) can improve its pharmacokinetics, stability and activity. In this study, ethosomes (ETs) were investigated for CUR and PIP delivery to protect the skin from damage induced by diesel particulate matter. ETs were produced by different strategies and characterized for their size distribution by photon correlation spectroscopy, for their morphology by transmission electron microscopy, and for their drug encapsulation efficiency by high-performance liquid chromatography. Franz cells enabled us to evaluate in vitro the drug diffusion from ETs. The results highlighted that ETs can promote the skin permeation of curcumin. The studies carried out on their antioxidant activity demonstrated an increase in the antioxidant power of CUR using a combination of CUR and PIP separately loaded in ETs, suggesting their possible application for the prevention of skin damage due to exogenous stressors. Ex vivo studies on human skin explants have shown the suitability of drug-loaded ETs to prevent the structural damage to the skin induced by diesel engine exhaust exposure.

This work is dealing with the use of polystyrene (PS) nanoparticles as substrates for bioanalytical specific interactions. Different techniques were used for the accurate characterization of the PS nanoparticles of 100 nm and 196 nm before coating them with a layer of antibodies against immunoglobulins of type E (aIgE), giving to the particle a specific functionality. The formation of the aIgE adsorbed layer was monitored using centrifugal particle separation (CPS) and centrifugal field flow fractionation (CF3) experiments, which allowed to determine the size changes and the adsorbed mass. Particle sizes were also measured with DLS, used both as stand-alone instrument and coupled to CF3 (CF3-DLS). The complementary information obtained from the CPS and CF3-DLS measurements allowed the estimation of the density of the aIgE shell. The proteins immobilized at the surface fully retained their activity, as proven by the reactions between the functionalized PS-aIgE particles and immunoglobulins of type E (IgE) dispersed in suspensions prepared on purpose., (Copyright © 2019. Published by Elsevier B.V.)

We report the use of inverse supercritical fluid extraction (SFE) and miniaturized asymmetrical flow field-flow fractionation (mAF4) for the preparation and subsequent analysis of titanium dioxide nanoparticles in model and commercial sunscreens. The approach allows for the fast and reliable fractionation and sizing of TiO 2 nanoparticles and their quantitation in commercial products. This new method represents a powerful and efficient tool for the verification of nanoparticle content in a wide range of matrixes, as demanded by recently introduced regulatory requirements. Furthermore, the use of carbon dioxide as an environmentally friendly solvent is in line with the increasing need for ecologically compatible analytical techniques.

The dimensional characterization of insoluble, inorganic particles, such as zinc oxide ZnO, dispersed in cosmetic or pharmaceutical formulations, is of great interest considering the current need of declaring the possible presence of nanomaterials on the label of commercial products. This work compares the separation abilities of Centrifugal- and Asymmetrical Flow Field-Flow Fractionation techniques (CF3 and AF4, respectively), equipped with UV-vis, MALS and DLS detectors, in size sorting ZnO particles, both as pristine powders and after their extraction from cosmetic matrices. ZnO particles, bare and superficially modified with triethoxycaprylyl silane, were used as test materials. To identify the most suitable procedure necessary to isolate the ZnO particles from the cosmetic matrix, two O/W and two W/O emulsions were formulated on purpose. The suspensions, containing the extracted particles ZnO, were separated by both Field-Flow Fractionation (FFF) techniques to establish a common analysis protocol, applicable for the analysis of ZnO particles extracted from three commercial products, sold in Europe for the baby skin care. Key aspects of this study were the selection of an appropriate dispersing agent enabling the particles to stay in stable suspensions (>24h)and the use of multiple detectors (UV-vis, MALS and DLS) coupled on-line with the FFF channels, to determine the particle dimensions without using the retention parameters. Between the two FFF techniques, CF3 revealed to be the most robust one, able to sort all suspensions created in this work., (Copyright © 2017 Elsevier B.V. All rights reserved.)

This study describes the preparation, characterization and in vitro release of monoolein aqueous dispersions (MAD) encapsulating quercetin (QT). As emulsifier, sodium cholate was employed at two different concentrations, namely 0.15% and 0.25% with respect to the total weight of the formulation. Cryogenic Transmission electron microscopy and X-ray analysis indicated that MAD015 are a mixture of vesicles and cubic structures, whilst MAD025 are mainly characterized by unilamellar vesicular structures. Photon correlation spectroscopy (PCS) and Sedimentation Field Flow Fractionation (SdFFF) showed a MAD size higher than 300 nm that over 100 days from analysis reduces up to 200 nm. In vitro Franz cell experiments showed that the two systems had a similar behaviour in the release of QT. Experiments on antioxidant activity of MAD containing QT demonstrated that their activity parallel with the content of encapsulated QT within the MAD formulations produced. Taken together these results allow us to conclude that MAD can be potentially proposed for the delivery of QT.

Field flow fractionation (FFF) techniques are used to successfully characterize several nanomaterials by sizing nano-entities and producing information about the aggregation/agglomeration state of nanoparticles. By coupling FFF techniques to specific detectors, researchers can determine particle-size distributions (PSDs), expressed as mass-based or number-based PSDs. This review considers FFF applications in the food, biomedical, and environmental sectors, mostly drawn from the past 4 y. It thus underlines the prominent role of asymmetrical flow FFF within the FFF family. By concisely comparing FFF techniques with other techniques suitable for sizing nano-objects, the advantages and the disadvantages of these instruments become clear. A consideration of select recent publications illustrates the state of the art of some lesser-known FFF techniques and innovative instrumental set-ups.

This study describes the preparation, characterisation and in vitro activity of nanostructured lipid carriers (NLCs) encapsulating natural molecules with antimicrobial activity, such as plumbagin, hydroquinon, eugenol, alpha-asarone and alpha-tocopherol. NLCs were prepared by melt and ultrasonication method, characterised by Cryo-TEM for morphology and SdFFF for dimensional distribution and active encapsulation yields. In vitro tests were conducted on bacteria, fungi and human cell cultures. In vitro tests demonstrated that plumbagin is strongly toxic towards F. oxysporum especially when active molecules are loaded on NLC. Plumbagin was completely non toxic on cyanobacterial model strain up to a threshold over which cell viability was completely lost. NLC loaded with active molecules showed a lower toxicity as compared to their free form on human cultured cells. Although further studies need to be performed, these systems can be potentially proposed to control phytopathogenic organisms.

Many advanced industrial and biomedical applications that use silver nanoparticles (AgNPs), require that particles are not only nano-sized, but also well dispersed, not aggregated and not agglomerated. This study presents two methods able to give rapidly sizes of monodispersed AgNPs suspensions in the dimensional range of 20-100nm. The first method, based on the application of Mie's theory, determines the particle sizes from the values of the surface plasmon resonance wavelength (SPR MAX ), read from the optical absorption spectra, recorded between 190nm and 800nm. The computed sizes were compared with those determined by transmission electron microscopy (TEM) and dynamic light scattering (DLS) and resulted in agreement with the nominal values in a range between 13% (for 20nm NPs) and 1% (for 100nm NPs), The second method is based on the masterly combination of the Sedimentation Field Flow Fractionation (SdFFF - now sold as Centrifugal FFF-CFFF) and the Optical Absorption Spectroscopy (OAS) techniques to accomplish sizes and quantitative particle size distributions for monodispersed, non-aggregated AgNPs suspensions. The SdFFF separation abilities, well exploited to size NPs, greatly benefits from the application of Mie's theory to the UV-vis signal elaboration, producing quantitative mass-based particle size distributions, from which trusted number-sized particle size distributions can be derived. The silver mass distributions were verified and supported by detecting off-line the Ag concentration with the graphite furnace atomic absorption spectrometry (GF-AAS)., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Specific information about the particle size distribution, agglomeration state, morphology, and chemical composition of four silica samples, used as additives in food and in personal care products, were achieved with a combination of analytical techniques. The combined use of differential centrifugal sedimentation (DCS), sedimentation field flow fractionation (SdFFF), and scanning and transmission electron microscopy (SEM and TEM) allows to classify the water dispersed samples as "nanomaterials" according to the EC definition. The mechanical stirring and the ultrasound treatment were compared as dispersion methods. The particle surface chemical composition, determined by particle-induced X-ray emission (PIXE) and X-ray photoelectron spectroscopy (XPS), assessed the different levels of purity between the pyrogenic and the precipitated silica and highlighted particle surface chemical composition modifications in the outer shell when dispersed by mechanical stirring. The potential toxic effects of silica on intestinal Caco-2 cells were investigated using MTS assay and by measuring lactate dehydrogenase (LDH) release and caspases 3/7 activity after 24 h of incubation. No or limited decrease of cell viability was observed for all particles regardless of dispersion procedure, suggesting a relative innocuity of these silica samples.

Many products used in everyday life are made with the assistance of nanotechnologies. Cosmetic, pharmaceuticals, sunscreen, powdered food are only few examples of end products containing nano-sized particles (NPs), generally added to improve the product quality. To evaluate correctly benefits vs. risks of engineered nanomaterials and consequently to legislate in favor of consumer's protection, it is necessary to know the hazards connected with the exposure levels. This information implies transversal studies and a number of different competences. On analytical point of view the identification, quantification and characterization of NPs in food matrices and in cosmetic or personal care products pose significant challenges, because NPs are usually present at low concentration levels and the matrices, in which they are dispersed, are complexes and often incompatible with analytical instruments that would be required for their detection and characterization. This paper focused on some analytical techniques suitable for the detection, characterization and quantification of NPs in food and cosmetics products, reports their recent application in characterizing specific metal and metal-oxide NPs in these two important industrial and market sectors. The need of a characterization of the NPs as much as possible complete, matching complementary information about different metrics, possible achieved through validate procedures, is what clearly emerges from this research. More work should be done to produce standardized materials and to set-up methodologies to determine number-based size distributions and to get quantitative date about the NPs in such a complex matrices.

This paper describes the production, characterization and in vivo activity of lipid nanocarriers (LN) containing a levodopa prodrug (LD-PD) with therapeutic potential in Parkinson's disease. LD is the mainstay of the pharmacotherapy of Parkinson's disease. However, after a good initial response, motor fluctuations, dyskinesia and loss of efficacy, develop over time, partly due to oscillations in plasma and brain levels of the drug. LD-PD was produced with the aim of prolonging the pharmacological activity of LD. To improve solubility, and simultaneously provide a long lasting release and therapeutic efficacy, the prodrug was formulated in tristearin/lecithin LN. The obtained formulation was homogeneous in particle size and remained stable for up to 2months from preparation. For the three different tested LD concentrations, namely 1.25, 2.5 and 5.0mg/ml, the morphological characterization revealed no substantial differences between unloaded and LD-PD loaded LN. The calorimetric test showed an interaction between the lipid phase and the loaded prodrug. In vitro studies using the dialysis method and enzymatic degradation procedure showed that the LD-PD loaded LN provided a controlled prodrug release. Finally, two behavioural tests specific to akinesia (bar test) or akinesia/bradykinesia (drag test) performed in 6-hydroxydopamine hemilesioned mice (a model of Parkinson's disease) demonstrated that the LD-PD loaded LN attenuated parkinsonian disabilities, showing a slightly reduced maximal efficacy but a longer lasting action (up to 24h) than an equal dose of LD. We conclude that LD-PD loaded LN may represent a future LD formulation useful in Parkinson's disease therapy., (Copyright © 2014 Elsevier B.V. All rights reserved.)

This study describes the preparation, characterization, and in vivo evaluation in rats of nanostructured lipid carriers (NLCs) encapsulating rimonabant (RMN) as prototypical cannabinoid antagonist. A study was conducted in order to optimize NLC production by melt and ultrasonication method. NLCs were prepared by alternatively adding the lipid phase into the aqueous one (direct protocol) or the aqueous phase into the lipid one (reverse protocol). RMN-NLCs have been characterized by cryogenic transmission electron microscopy (cryo-TEM), X-ray, photon correlation spectroscopy (PCS) and sedimentation field flow fractionation (SdFFF). Reverse NLCs were treated with polysorbate 80. RMN release kinetics have been determined in vitro by dialysis method. In vivo RMN biodistribution in rats was evaluated after intranasal (i.n.) administration of reverse RMN-NLC. The reverse protocol enabled to prevent the lost of lipid phase and to achieve higher RMN encapsulation efficacy (EE) with respect to the direct protocol (98% w/w versus 67% w/w). The use of different protocols did not affect NLC morphology and dimensional distribution. An in vitro dissolutive release rate of RMN was calculated. The in vivo data indicate that i.n. administration of RMN by reverse NLC treated with polysorbate 80 increased RMN concentration in the brain with respect to the drug in solution. The nanoencapsulation protocol presented here appears as an optimal strategy to improve the low solubility of cannabinoid compounds in an aqueous system suitable for in vivo administration., (Copyright © 2014 Elsevier B.V. All rights reserved.)

This study describes the preparation, characterization, and biodistribution of radiolabelled nanostructured lipid carriers (NLCs) especially designed for in vivo tomographic study. A preliminary formulative study was conducted in order to incorporate (99m)Tc based tracer in NLCs. At this aim a (99m)Tc complex containing a terminal (99m)Tc ≡ N multiple bond ([(99m)Tc]N-DBODC2) has been synthesized and included in NLCs produced by a stirring and ultrasonication method. The morphological and dimensional characteristics of the produced NLCs have been accurately investigated by a number of specific techniques, including: cryogenic transmission electron microscopy, X-ray, photon correlation spectroscopy and sedimentation field flow fractionation. The obtained NLCs were employed for achieving in vivo tomographic images of the rat body by small-animal SPECT scanner that enabled the investigation of NLC biodistribution after intraperitoneal, intravenous, intranasal and oral administration. NLC production protocol allowed to firmly encapsulate the radiotracer within the nanoparticles. In vivo studies evidenced that NLC remained stable in vivo, suggesting their suitability as controlled release system for drugs and radiochemical for therapeutic and diagnostic purposes. Moreover the high resolution images obtained by the SPECT technique allowed to detect NLC presence in brown fat tissue, suggesting NLC therapeutic application for treating human obesity and related metabolic disorders., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Different analytical techniques, sedimentation flow field fractionation (SdFFF), asymmetrical flow field flow fractionation (AF4), centrifugal liquid sedimentation (CLS) and dynamic light scattering (DLS) have been used to give complementary size information about suspensions of silver nanoparticles (AgNPs) in the size range of 20-100 nm by taking advantage of the different physical principles on which are based. Particle morphology was controlled by TEM (Transmission Electron Microscopy). Both SdFFF and AF4 were able to accurately size all AgNPs; among sedimentation based techniques, CLS underestimated the average sizes of larger samples (70 and 100 nm), but it produced the best separation of bimodal mixtures Ag40/60 and Ag40/70 mix compared to SdFFF. On the contrary, DLS overestimated the average sizes of the smallest samples (20 and 30 nm) and it was unable to deal with bimodal mixtures. Quantitative mass and number particle size distributions were also calculated starting from UV-vis signals and ICP-MS data and the results evaluated as a means to address the issue of determining nanoparticle size distributions as required for implementation of European regulations relating to labeling of nanomaterials in consumer products. The results are discussed in light of possible particle aggregation state, analysis repeatability, size resolution and quantitative recoveries.

Context: Zidovudine (AZT) is employed against AIDS and hepatitis; its use is limited by active efflux transporters (AETs) that induce multidrug resistance for intracellular therapies and hamper AZT to reach the brain. Ursodeoxycholic acid (UDCA) conjugation with AZT (prodrug UDCA-AZT) allows to elude the AET systems., Objective: To investigate the effect of the Pluronic F68 coating on the loading, release and stability of poly(D,L lactide-co-glicolide) nanoparticles (NPs) embedded with UDCA-AZT., Materials and Methods: The mean diameter of the NP prepared by nanoprecipitation or emulsion/solvent evaporation methods was determined using both photon correlation spectroscopy and sedimentation field-flow fractionation; particle morphology was detected by scanning electron microscope. The stability of the free and encapsulated UDCA-AZT was evaluated in rat liver homogenates by high-performance liquid chromatography analysis., Results and Discussion: The mean diameter of the NPs was found to be ∼ 600 nm with a relatively high polydispersity. The NPs obtained by emulsion/solvent evaporation were not able to control the prodrug release, differently from NPs obtained by nanoprecipitation. The presence of the Pluronic coating did not substantially modify the kinetics of the drug release, or the extent of the burst effect that were instead only influenced by the preparation parameters. UDCA-AZT incorporated in the NPs was more stable in the rat liver homogenates than the free prodrug and no influence of the Pluronic coating was observed., Conclusions: Considering the different potential applications of nanoparticles coated and uncoated with Pluronic (brain and macrophage targeting, respectively), both of these nanoparticle systems could be useful in the therapies against HIV.

The present study describes the production and characterization of monoolein aqueous dispersions (MAD) as drug delivery systems for curcumin (CR). MAD based on monoolein and different emulsifiers have been produced and characterized. Morphology and dimensional distribution have been investigated by Cryogenic Transmission Electron Microscopy (cryo-TEM), X-ray and Photon Correlation Spectroscopy (PCS). Monoolein in different mixtures with sodium cholate, sodium caseinate, bentonite and poloxamer resulted in heterogeneous dispersions constituted of unilamellar vesicles, cubosomes and sponge type phases, depending on the employed components, as found by cryo-TEM and X-ray studies. CR was encapsulated with entrapment efficiencies depending on the MAD composition, particularly the highest was reached in the case of monoolein/poloxamer/sodium cholate mixture. The same mixture was able to maintain CR stability also after 6 months. CR release modalities were in vitro investigated in order to mimic a possible subcutaneous administration of MAD. It was found that MAD constituted of monoolein/poloxamer and monoolein/poloxamer/sodium cholate mixtures were able to sustain CR release. MAD viscous vehicles were produced by xanthan gum. CR percutaneous absorption has been studied in vitro using excised human skin membranes [stratum corneum epidermis (SCE)] mounted into Franz cells. It was found that fluxes (Fn) of CR incorporated in MAD are influenced by the presence of monoolein based nanosystems. In particular xanthan gum based MAD better control CR diffusion from MAD., (© 2013.)

Four types of SiO2, available on the market as additives in food and personal care products, were size characterized using Sedimentation Field Flow Fractionation (SdFFF), SEM, TEM and Photon Correlation Spectroscopy (PCS). The synergic use of the different analytical techniques made it possible, for some samples, to confirm the presence of primary nanoparticles (10 nm) organized in clusters or aggregates of different dimension and, for others, to discover that the available information is incomplete, particularly that regarding the presence of small particles. A protocol to extract the silica particles from a simple food matrix was set up, enriching (0.25%, w w(-1)) a nearly silica-free instant barley coffee powder with a known SiO2 sample. The SdFFF technique, in conjunction with SEM observations, made it possible to identify the added SiO2 particles and verify the new particle size distribution. The SiO2 content of different powdered foodstuffs was determined by graphite furnace atomic absorption spectroscopy (GFAAS); the concentrations ranged between 0.006 and 0.35% (w w(-1)). The protocol to isolate the silica particles was so applied to the most SiO2-rich commercial products and the derived suspensions were separated by SdFFF; SEM and TEM observations supported the size analyses while GFAAS determinations on collected fractions permitted element identification., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Poly(lactic-co-glycolic acid) particles in the 200-400-nm size range were formulated through nanoprecipitation and solvent evaporation methods. Different concentrations of the polymer and stabilizer (Pluronic® F 68) were tested in order to identify the best conditions for making poly(lactic-co-glycolic acid) particles of suitable size, stable in time, and to be used as carriers for brain-targeting drugs. The particles with the best characteristics for delivery system design were those formulated by nanoprecipitation with an organic/water phase ratio of 2:30, a polymer concentration of 25 mg/mL, and a surfactant concentration of 0.83 mg/mL; their surface charge was reasonably negative (approximately -27 mV) and the average size of the almost monodisperse population was roughly 250 nm. Particle characterization was obtained through ζ-potential measurements, scanning electron microscope observations, and particle size distribution determinations; the latter achieved by both photon-correlation spectroscopy and sedimentation field flow fractionation. Sedimentation field flow fractionation, which is considered more reliable than photon-correlation spectroscopy in describing the possible particle size distribution modifications, was used to investigate the effects of 3 months of storage at 4 °C had on the lyophilized particles. Figure Particle size ditribution from the SdFFF and the PCS techniques.

In this study a formulation suitable to be applied on oral and/or vaginal mucosa has been developed for the treatment of fungal infections. The aim of the research is a comparison between clotrimazole (CLO) containing semisolid formulations based on monoolein aqueous dispersion (MAD) or nanostructured lipid carrier (NLC). MAD and NLC have been characterized in terms of morphology and dimensional distribution by cryogenic Transmission Electron Microscopy (cryo-TEM) and Photon Correlation Spectroscopy (PCS). CLO was encapsulated with high entrapment efficiency both in MAD and in NLC, according to Sedimentation Field Flow Fractionation (SdFFF) combined with HPLC. CLO recovery in MAD and NLC has been investigated by time. In order to obtain formulations with suitable viscosity for mucosal application, MAD was diluted with a carbomer gel, while NLC was directly viscosized by the addition of poloxamer 407 in the dispersion. The rheological properties of MAD and NLC after viscosizing have been investigated. Franz cell has been employed to study CLO diffusion from the different vehicles, evidencing diffusion rates from MAD and NLC superimposable to that obtained using Canesten(®). An anticandidal activity study demonstrated that both CLO-MAD and CLO-NLC were more active against Candida albicans with respect to the pure drug., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Nine cheap eye shadow products were analyzed through graphite furnace atomic absorption spectrometry (GF-AAS) to quantify their Cr, Co and Ni contents, all known to be skin sensitizers. In many cases, the concentrations were higher than 1 or 5 ppm (μg/g), i.e. the limits recommended in the scientific literature to minimize the risk of reaction in particularly sensitive subjects. In most cases, the concentration of Cr was higher than that of Ni and Co, up to a limit case of 150 mg/g. In this particular sample, the potential amount of Cr that could be released in ionic form was determined in sweat simulating solutions by GF-AAS and confirmed through a specific spectrofluorimetric method; the results indicated the presence of approximately 80-90 ppb (ng/g) of Cr(3+). The water dispersible particles were isolated from the eye shadow powders through a simple solvent extraction procedure. The aqueous suspensions were then sorted through sedimentation field flow fractionation (SdFFF) and the particles sizes were calculated from experimental fractograms using theory. For the most part, the computed sizes were in the micron range, as confirmed by some SEM photographs taken on fractions collected during the separations. The SdFFF coupled off-line with the GFAAS enabled elemental characterization of pigment particles as a function of size. This finding reduces the concern that the ingredients of such makeup formulations may contain nanoparticles., (Copyright © 2012 Elsevier B.V. All rights reserved.)

The physico-chemical properties and in vivo efficacies of two nanoparticulate systems delivering the antiparkinsonian drug bromocriptine (BC) were compared in the present study. Monoolein Aqueous Dispersions (MADs) and Nanostructured Lipid Carriers (NLCs) were produced and characterized. Cryogenic transmission electron microscopy (cryo-TEM) and X-ray diffraction revealed the morphology of MAD and NLC. Dimensional distribution was determined by Photon Correlation Spectroscopy (PCS) and Sedimentation Field Flow Fractionation (SdFFF). In particular, BC was shown to be encapsulated with high entrapment efficiency both in MAD and in NLC, according to SdFFF combined with HPLC. Two behavioral tests specific for akinesia (bar test) or akinesia/bradykinesia (drag test) were used to compare the effects of the different BC formulations on motor disabilities in 6-hydroxydopamine hemilesioned rats in vivo, a model of Parkinson's disease. Both free BC and BC-NLC reduced the immobility time in the bar test and enhanced the number of steps in the drag test, although the effects of encapsulated BC were longer lasting (5h). Conversely, BC-MAD was ineffective in the bar test and improved stepping activity in the drag test to a much lower degree than those achieved with the other preparations. We conclude that MAD and NLC can encapsulate BC, although only NLC provide long-lasting therapeutic effects possibly extending BC half-life in vivo., (Copyright © 2011 Elsevier B.V. All rights reserved.)

WO₃ colloidal suspensions obtained through a simple sol-gel procedure were subjected to a controlled temperature aging process whose time evolution in terms of particle mass and size distribution was followed by sedimentation field flow fractionation (SdFFF) and flow field flow fractionation (FlFFF). The experiments performed at a temperature of 60 °C showed that in a few hours the initially transparent sol of WO₃ particles, whose size was less than 25 nm, undergoes a progressive size increase allowing nanoparticles to reach a maximum equivalent spherical size of about 130 nm after 5 h. The observed shift in particle size distribution maxima (SdFFF), the broadening of the curves (FlFFF) and the SEM-TEM observations suggest a mixed mechanism of growth-aggregation of initial nanocrystals to form larger particles. The photoelectrochemical properties of thin WO₃ films obtained from the aged suspensions at regular intervals, were tested in a biased photoelectrocatalytic cell with 1M H₂SO₄ under solar simulated irradiation. The current-voltage polarization curves recorded in the potential range 0-1.8 V (vs. SCE) showed a diminution of the maximum photocurrent from 3.7 mA cm⁻² to 2.8 mA cm⁻² with aging times of 1h and 5h, respectively. This loss of performance was mainly attributed to the reduction of the electroactive surface area of the sintered particles as suggested by the satisfactory linear correlation between the integrated photocurrent and the cyclic voltammetry cathodic wave area of the W(VI)→W(V) process measured in the dark., (Copyright © 2010 Elsevier B.V. All rights reserved.)

The present study concerns the percutaneous absorption of naproxen (NPX), as model anti-inflammatory drug, included in liposome formulations constituted of different lipids: stratum corneum lipids (SCL) and phosphatidylcholine/cholesterol (PC/CHOL). Liposome dispersions were produced using two different methods: reverse-phase evaporation (REV) and thin layer evaporation (TLE). Morphology and dimensions of the disperse phase were characterized by cryo-transmission electron microscopy (cryo-TEM) and photon correlation spectroscopy, respectively. X-ray diffraction was employed to determine the structural organization of the vesicles. In vitro diffusion was studied by Franz cell on liposome dispersions viscosized by carbomer. Tape stripping was performed to investigate in vivo the performance of differently composed liposomes as NPX delivery system. Cryo-TEM showed spherical vesicles and bigger irregular elongated nanoparticles for TLE SCL liposomes. REV resulted in spherical and elongated multilamellar vesicles. Also X-ray diffraction evidenced L alpha or L beta multilamellar vesicles for PC/CHOL and SCL liposome respectively. The in vitro study showed a lower NPX flux for SCL with respect to PC/CHOL liposome. Tape stripping corroborate the in vitro findings regarding SCL, suggesting that liposomes create a drug reservoir mixing with SC lipids, whilst PC/CHOL liposome promoted NPX permeation through the skin. Liposome lipid composition seems to affect NPX permeation through the skin., ((c) 2009 Wiley-Liss, Inc. and the American Pharmacists Association)

Gold nanoparticles (GNPs) have been synthesized through the citrate reduction method; the citrate/gold(III) ratio was changed from 1:1 up to 10:1 and the size of the resulting nanoparticles was measured by sedimentation field-flow fractionation (SdFFF). Experimental data showed that the GNPs size decreases in the ratio range 1:1-3:1 and then increases from 5:1 to 10:1 passing through a plateau region in between, and is almost independent of the precursor solution concentrations. In the zone of minimum diameters the synthetic process does not produce monodispersed GNPs but often multiple distributions, very close in size, are observed as evidenced by the particle size distributions (PSDs) derived from the SdFFF fractograms. UV-vis spectrophotometry, being the most common technique employed in the optical characterization of nanoparticles suspensions, was used throughout this work. A confirmation of the nucleation-aggregation-fragmentation mechanism was inferred from the cross-correlation between UV-vis and SdFFF results.

A new method for determining the size of titanium dioxide particles is proposed and assayed in a commercial sunscreen product. Today many sun protection cosmetics incorporate physical UV filters as active ingredients, and there are no official methods for determining these compounds in sunscreen cosmetics. Here flow field-flow fractionation (FlFFF) has been tested, first to sort two different types of TiO2 nano- and microstandard materials (AeroxideTiO2 Degussa P-25 and TiO2 rutile 0.1-0.2-microm size) and then to fractionate TiO2 particles, extracted from a commercial sunscreen lotion. All the TiO2 FlFFF separations were detected by UV but during elution fractions were collected and their Ti content measured by inductively coupled plasma-atomic emission spectrometer (ICP-AES); the Ti concentration profiles obtained by ICP-AES were well correlated with the UV signals. The TiO2 particle mass-size distribution were calculated from the UV profiles. This methodology is relatively simple and rapid, and the sample treatment is as a whole easy and low cost.

In the present paper, the capabilities of differential field-flow fractionation, i. e., the determination of an incremental quantity of a colloidal species, e. g., an uptake adsorbed mass, determined by the joint use of two independent FFF measurements, over a species and the same modified species respectively, are considered. The different error types, those related to the retention time determinations and those coming from the operating parameter fluctuations were considered. The different components were computed with reference to SdFFF determinations of bare polystyrene (PS) submicronic particles and the same PS particles covered by IgG. Comparison was made between theoretically computed precision and experiments. The error coming from the experimental measurement of retention times was identified to be the main source of errors. Accordingly, it was possible to make explicit the detection limits and the confidence intervals of the adsorbed mass uptake, as a function of experimental quantities such as the retention ratio, the detector calibration ratio, the injected quantity, the baseline noise, and the void time relative error. An experimentally determined and theoretically foreseen dependence of both the experimental detection and confidence limits (approximately +/- 10(-17) g) on the square root of the injected concentration, for constant injected volume, was found.

The amount of immunoglobulin A (IgA) adsorbed on the surface of two different samples of polystyrene (PS) microbeads was evaluated using differential sedimentation field flow fractionation (SdFFF) analyses. For the first time, the SdFFF separations obtained by using, as mobile phase, solutions common to many biochemical procedures and applications have been compared and discussed. Good separation results were achieved in the different carriers, and the SdFFF gave equivalent mass per particle values in all carriers provided that the pH and ionic strength conditions of the eluents were well controlled. The IgA adsorption process onto PS occurred by maintaining unaltered the capacity of the PS-IgA substrate to selectively recognize anti-IgA (aIgA), as proven by elution of the ternary complex PS-IgA-aIgA and from the monitored lack of reaction when the PS-IgA was placed in contact with aIgE.

Poly(lactic acid) (PLA) nanoparticles were synthesized using a modified evaporation method, testing two different surfactants (sodium cholate and Pluronic F68) for the process. During their formulation the prodrug 5'-octanoyl-CPA (Oct-CPA) of the anti-ischemic N(6)-cyclopentyladenosine (CPA) was encapsulated. Three different purification methods were compared with respect to the influence of surfactant on the size characteristics of the final nanoparticle product. Flow and sedimentation field-flow fractionation techniques (FlFFF and SdFFF, respectively) were used to size characterize the five poly(lactic acid) particle samples. Two different combinations of carrier solution (mobile phase) were employed in the FlFFF analyses, while a solution of poly(vinyl alcohol) was used as mobile phase for the SdFFF runs. The separation performances of the two techniques were compared and the particle size distributions (PSDs), derived from the fractograms, were interpreted with the support of observations by scanning electron microscopy. Some critical aspects, such as the carrier choice and the channel thickness determination for the FlFFF, have been investigated. This is the first comprehensive comparison of the two FFF techniques for characterizing non-standard particulate materials. The two FFF techniques proved to be complementary and gave good, congruent and very useful information on the size distributions of the five poly(lactic acid) particle samples.

Purpose: The present study concerns the production and characterization of monooleine (MO) dispersions as drug delivery systems for indomethacin, taken as model anti-inflammatory drug., Methods: Dispersions were produced by emulsification and homogenization of MO and poloxamer in water. Morphology and dimensional distribution of the disperse phase have been characterized by cryo-transmission electron microscopy and photon correlation spectroscopy, respectively. X-ray diffraction has been performed to determine the structural organization of the disperse phase. Sedimentation field flow fractionation (SdFFF) has been performed to investigate drug distribution in the dispersion. An in vitro diffusion study was conducted by Franz cell associated to stratum corneum epidermis membrane on cubosome dispersions viscosized by carbomer. In vivo studies based on skin reflectance spectrophotometry and tape stripping were performed to better investigate the performance of cubosome as indomethacin delivery system., Results: Microscopy studies showed the coexistence of vesicles and cubosomes. X-ray diffraction revealed the presence of a bicontinuous cubic phase of spatial symmetry Im3m (Q229). SdFFF demonstrated that no free drug was present in the dispersion. Indomethacin incorporated in viscosized MO dispersions exhibited a lower flux with respect to the analogous formulation containing the free drug in the aqueous phase and to the control formulation based on carbomer gel. Reflectance spectroscopy demonstrated that indomethacin incorporated into MO dispersions can be released in a prolonged fashion. Tape-stripping experiments corroborated this finding., Conclusions: MO dispersions can be proposed as nanoparticulate systems able to control the percutaneous absorption of indomethacin.