Dry coating of solid dosage forms: an overview of processes and applications

Dry coating techniques enable manufacturing of coated solid dosage forms with no, or very limited, use of solvents. As a result, major drawbacks associated with both organic solvents and aqueous coating systems can be overcome, such as toxicological, environmental, and safety-related issues on the one hand as well as costly drying phases and impaired product stability on the other. The considerable advantages related to solventless coating has been prompting a strong research interest in this field of pharmaceutics. In the article, processes and applications relevant to techniques intended for dry coating are analyzed and reviewed. Based on the physical state of the coat-forming agents, liquid- and solid-based techniques are distinguished. The former include hot-melt coating and coating by photocuring, while the latter encompass press coating and powder coating. Moreover, solventless techniques, such as injection molding and three-dimensional printing by fused deposition modeling, which are not purposely conceived for coating, are also discussed in that they would open new perspectives in the manufacturing of coated-like dosage forms.     

Modeled Microgravity Affects Fibroblast Functions Related to Wound Healing

Wound healing is crucial for the survival of an organism. Therefore, in the perspective of space exploration missions, it is important to understand if and how microgravity conditions affect the behavior of the cell populations involved in wound healing and the evolution of the process. Since fibroblasts are the major players in tissue repair, this study was focused on the behavior of fibroblasts in microgravity conditions, modeled by a RCCS. Cell cytoskeleton was studied by immunofluorescence microscopy, the ability to migrate was assessed by microchemotaxis and scratch assay, and the expression of markers of fibroblast activation, angiogenesis, and inflammation was assessed by western blot. Results revealed that after cell exposure to modeled microgravity conditions, a thorough rearrangement of microtubules occurred and α-SMA bundles were replaced by a tight network of faulty and disorganized filaments. Exposure to modeled microgravity induced a decrease in α-SMA and E-CAD expressions. Also, the expression of the pro-angiogenic protein VEGF decreased, while that of the inflammatory signal COX-2 increased. Fibroblast ability to adhere, migrate, and respond to chemoattractants (PRP), closely related to cytoskeleton integrity and membrane junctions, was significantly impaired. Nevertheless, PRP was able to partially restore fibroblast migration.     

Integrin-targeting with peptide-bioconjugated semiconductor-magnetic nanocrystalline heterostructures

Binary asymmetric nanocrystals (BNCs), composed of a photoactive TiO₂ nanorod joined with a superparamagnetic γ-Fe₂O₃ spherical domain, were embedded in polyethylene glycol modified phospholipid micelle and successfully bioconjugated to a suitably designed peptide containing an RGD motif. BNCs represent a relevant multifunctional nanomaterial, owing to the coexistence of two distinct domains in one particle, characterized by high photoactivity and magnetic properties, that is particularly suited for use as a phototherapy and hyperthermia agent as well as a magnetic probe in biological imaging. We selected the RGD motif in order to target integrin expressed on activated endothelial cells and several types of cancer cells. The prepared RGD-peptide/BNC conjugates, comprehensively monitored by using complementary optical and structural techniques, demonstrated a high stability and uniform dispersibility in biological media. The cytotoxicity of the RGD-peptide/BNC conjugates was studied in vitro. The cellular uptake of RGD-peptide conjugates in the cells, assessed by means of two distinct approaches, namely confocal microscopy analysis and emission spectroscopy determination in cell lysates, displayed selectivity of the RGD-peptide-BNC conjugate for the αvβ3 integrin. These RGD-peptide-BNC conjugates have a high potential for theranostic treatment of cancer.

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Mixed Fluorinated/Hydrogenated Self‐Assembled Monolayer‐Protected Gold Nanoparticles: In Silico and In Vitro Behavior

Gold nanoparticles (AuNPs) covered with mixtures of immiscible ligands present potentially anisotropic surfaces that can modulate their interactions at complex nano–bio interfaces. Mixed, self‐assembled, monolayer (SAM)‐protected AuNPs, prepared with incompatible hydrocarbon and fluorocarbon amphiphilic ligands, are used here to probe the molecular basis of surface phase separation and disclose the role of fluorinated ligands on the interaction with lipid model membranes and cells, by integrating in silico and experimental approaches. These results indicate that the presence of fluorinated amphiphilic ligands enhances the membrane binding ability and cellular uptake of gold nanoparticles with respect to those coated only with hydrogenated amphiphilic ligands. For mixed monolayers, computational results suggest that ligand phase separation occurs on the gold surface, and the resulting anisotropy affects the number of contacts and adhesion energies with a membrane bilayer. This reflects in a diverse membrane interaction for NPs with different surface morphologies, as determined by surface plasmon resonance, as well as differential effects on cells, as observed by flow cytometry and confocal microscopy. Overall, limited changes in monolayer features can significantly affect NP surface interfacial properties, which, in turn, affect the interaction of SAM‐AuNPs with cellular membranes and subsequent effects on cells.     

High‐Density Sb2Te3 Nanopillars Arrays by Templated,Bottom‐Up MOCVD Growth

Sb₂Te₃ exhibits several technologically relevant properties, such as high thermoelectric efficiency, topological insulator character, and phase change memory behavior. Improved performances are observed and novel effects are predicted for this and other chalcogenide alloys when synthetized in the form of high‐aspect‐ratio nanostructures. The ability to grow chalcogenide nanowires and nanopillars (NPs) with high crystal quality in a controlled fashion, in terms of their size and position, can boost the realization of novel thermoelectric, spintronic, and memory devices. Here, it is shown that highly dense arrays of ultrascaled Sb₂Te₃ NPs can be grown by metal organic chemical vapor deposition (MOCVD) on patterned substrates. In particular, crystalline Sb₂Te₃ NPs with a diameter of 20 nm and a height of 200 nm are obtained in Au‐functionalized, anodized aluminum oxide (AAO) templates with a pore density of ≈5 × 10¹⁰ cm^?2. Also, MOCVD growth of Sb₂Te₃ can be followed either by mechanical polishing and chemical etching to produce Sb₂Te₃ NPs arrays with planar surfaces or by chemical dissolution of the AAO templates to obtain freestanding Sb₂Te₃ NPs forests. The illustrated growth method can be further scaled to smaller pore sizes and employed for other MOCVD‐grown chalcogenide alloys and patterned substrates.     

Anisotropies of the g-factor tensor and diamagnetic coefficient in crystal-phase quantum dots in InP nanowires

Nano Research - Crystal-phase low-dimensional structures offer great potential for the implementation of photonic devices of interest for quantum information processing. In this context, unveiling...     

Dispersion and survival of Escherichia coli O157:H7 and Salmonella Typhimurium during the production of marinated beef inside skirt steaks and tri-tip roasts

To determine the depth of pathogen dispersion and the ability of pathogens to survive in enhanced beef products and spent marinade, beef inside skirt steaks and tri-tip roasts were vacuum tumbled with two commercial marinades. The marinades were inoculated with Escherichia coli O157:H7 and Salmonella Typhimurium, resulting in an approximate count of 5.2 log CFU/ml. Both inside skirt steaks and tri-tip roasts were vacuum tumbled for 1 h and sampled immediately after tumbling (day 0), or were vacuum packaged, stored (ca. 4°C), and sampled on days 7 and 14. Samples of the spent marinade were taken after tumbling (day 0) and on days 3 and 7. For both marinades, Salmonella Typhimurium and E. coli O157:H7 were dispersed throughout the inside skirt steaks during vacuum tumbling. Although Salmonella Typhimurium and E. coli O157:H7 for the skirt steaks were still detectable after 14 days of storage, the log values were lower than those on days 0 and 7. For the tri-tip roasts, the pathogen distribution varied, depending on the thickness of the roasts, and pathogens were detectable on days 0, 7, and 14. The spent marinade sampled on days 0, 3, and 7 showed that the pathogens survived at refrigerated temperatures. Because pathogens can transfer to the interior of beef inside skirt steaks and tri-tip roasts when vacuum tumbled with contaminated marinade and survived during refrigerated storage, establishments should consider the potential food safety risks associated with reuse of marinade during the production of vacuum-tumbled beef products.     

氢醌化合物对针叶木硫酸盐纸浆氧脱木素的影响

研究了具有氧化还原性的氢醌类化合物作为氧脱木素过程的添加物.结果表明,氢醌的加入可以降低纸浆的卡伯值,提高氧脱木素的选择性.其原因是氢醌的存在可以提高O2转化成为含氧的活性反应产物,加速木素中甲氧基的脱除,有利于破坏木素的结构和脱除木素.     

Immunohistochemical detection and quantification of T cells in the small intestine of Isospora suis-infected piglets--influence of fixation technique and intestinal segment

Quantification of immunohistochemical results constitutes an important tool in the analysis of cells and tissue that is not readily replaced by other techniques. For reliable quantification, it is essential to consider factors such as tissue fixation and tissue sampling. We report a study on the model of the intestine of Isospora suis‐infected piglets, in which we addressed (1) whether the quantity of detectable T cells in the intestinal mucosa is the same in formalin‐, HOPE®‐, and cryo‐conserved material or whether the amounts of T cells at least correlate with one another; and (2) whether single jejunal segments differ in regard to the quantity of mucosal T cells and variability of lymphocyte infiltration. Quantification of T cells in histological sections of different parts of the jejunum of 15‐22 day old piglets infected with I. suis was performed using an anti‐CD3‐antibody and stereological point counting. Area fractions of T‐cell profiles per intestinal mucosa profile were higher in cryo‐conserved samples than in HOPE®‐ and formalin‐conserved material but no correlation between different fixations could be found. The proximal part of the jejunum contained fewer T cells compared with mid‐ and end‐jejunum. Coefficients of variation did not differ between the intestinal segments. For quantification of T cells in the gut mucosa of piglets infected with I. suis, the cryo‐conserved mid jejunum seems most suitable in cases when unbiased sampling of the complete intestine is not feasible. It is generally not possible to compare quantitative results of immunostaining in samples conserved by different methods. Microsc. Res. Tech., 2011. © 2011 Wiley‐Liss, Inc.