1,720,982 research outputs found
Electrospun Plasma-assisted Functionalized Ocular Inserts for Triamcinolone Acetonide Delivery
Full text linkTopically administered ocular Drug Delivery Systems are the most desirable formulations for the treatment of ocular chronic diseases, being the most simple, convenient and patient-friendly ocular route of administration, despite it requires prolonged and continuous treatment over time. At this regard, ocular insert represent an innovative and effective strategy. Ocular inserts are solid/semisolid sterile preparations characterized by dimensions and shape specifically designed for topical ocular administration. They are able to rapidly adhere on the ocular surface and remain in situ for prolonged period while assuring a controlled drug release and potentially increasing drug transcorneal absorption. Based on these assumptions, the aim of this work was to opportunely design and characterize novel useful polymeric inserts based on a 3D scaffold. Poly-butylene succinate (PBS) scaffolds were prepared by electrospinning, functionalized with biopolymers (inulin, poly(hydroxyethyl)aspartamide [PHEA], heparin) by plasma-assisted reaction and loaded with triamcinolone acetonide (TA). The obtained products were evaluated in terms of physico-chemical, technological-applicative and biological properties. Ocular inserts resulted non-bioerodible, with a very low swelling degree and a high drug loading ability, cytocompatible and extremely mucoadhesive. Moreover, inserts are also able to slowly release TA after firmly adhering on the corneal tissue. This translates into a significant increase of transcorneal permeation and penetration (enhancement of both Kp and Ka values up to an order magnitude). In conclusion, inserts can be an effective strategy to increase patient compliance by reducing the frequency of administration and avoiding pulsatile drug entry into the eye
Mucoadhesive PEGylated inulin-based self-assembling nanoparticles: In vitro and ex vivo transcorneal permeation enhancement of corticosteroids
No full textAs transcorneal drug delivery is still a challenge, the scope of the present study was to prepare useful nanosystems able to enhance transcorneal permeation/penetration of drugs. Moreover, this work aims to evaluate the effectiveness of inulin-based nanosystems in the specific field of ocular drug delivery and the effect of PEG chains to promote mucoadhesion, stability and transcorneal penetration/permeation enhancer effect of self-assembling nanoparticles in vitro (transwell systems and HCE) and ex vivo (Franz cells and bovine cornea). In particular, inulin was chosen as the starting natural polysaccharide polymer to design a novel amphiphilic derivative named INU-EDA-RA-PEG capable of self-assembling to form self-assembling nanoparticles and corticosteroids-loaded self-assembling nanoparticles. As observed, self-assembling nanoparticles show appropriate particle size values, mucoadhesivity and cytocompatibility. Moreover, self-assembling nanoparticles are able to act efficiently as permeation/penetration enhancer. Additionally, the presence of PEG has positive influence. Thus, the developed inulin-based nanosystems represent a promising tool to improve transcorneal delivery of corticosteroids
HYALURONIC ACID BASED-MICELLES FOR OFF-LABEL USE OF IMATINIB IN RETINOPATHIES TREATMENT
No full textThe aim of this work was to obtain polymeric micelles able to cross corneal barrier and to improve the permeation of imatinib free base. Micelles were prepared by using hyaluronic acid (HA) derivatives containing ethylenediamine (EDA), chains of hexadecyl (C16), polyethylene glycol (PEG) and/or L-carnitine (CRN). The resulting samples, named as HA-EDA-C16, HA-EDA-C16-PEG and HA-EDA-C16-CRN micelles, were designed to allow a non-invasive way of administration, i.e. topical ocular instillation. These nanocarriers showed an optimal particle size in aqueous media and mucoadhesive properties. Imatinib-loaded micelles were able to interact with corneal barrier and to promote imatinib transcorneal permeation and penetration. An interesting in vitro study was conducted to investigate imatinib inhibitory effect on a choroideal neovascularization process (1). Imatinib was able to inhibit endothelial cell sprouting and to reduce the formation of functional vessels. In addition, imatinib released from polymeric micelles was able to inhibit cell tube formation and to promote cell tube disruption. Obtained results suggested that prepared micelles could represent optimal candidates for off-label use of imatinib in the treatment of retinopathies
Preliminary Studies for the Preparation of Casein-loaded Liposomes to Inhibit Aβ1-40 Fibrillogenesis
Full text linkαs1-Casein is a natural protein which constitutes the most prevalent form of casein in bovine milk. αs1-Casein is amphiphilic, almost unfolded, and consist of two highly hydrophobic zones separated by an hydrophilic region. Previous studies have demonstrated the ability of αs1-Casein to inhibit in vitro the nucleation phase of amyloid β-peptide (Aβ) fibrillogenesis by sequestering Aβ species on its surface. One of the main hallmark for Alzheimer Disease (AD) is the extracellular deposition in brain tissues of proteinaceous plaques, rich of well-ordered Aβ peptide amyloid aggregates. Although such an evidence, oligomeric intermediates in the fibrillogenesis have been discovered to be the most toxic species able to interfere with membranes and disturbing the cell functioning. In this context, a challenging therapeutic approach could target such early toxic oligomeric species. In order to exploit the inhibiting action of αs1-Casein as a possible AD treatment, it is crucial to define a controlled method to efficiently load, protect and deliver the protein to the brain. Liposomes are spherical phospholipids-based vesicles characterized by excellent biocompatibility and biodegradability, low toxicity, ability to incorporate and protect both hydrophilic and hydrophobic drugs as well as to cross the Blood Brain Barrier in order to access the Central Nervous System. Based on all these considerations, novel proteoliposomes composed by phospholipids, cholesterol and αs1-Casein were prepared and characterized. The proteoliposome preparation protocol was optimized in order to obtain the best results. Nanosystems were characterized by different biophysics techniques, such as light scattering, zeta-potential, laurdan fluorescence, chromatography and AFM imaging
Imatinib-Loaded Micelles of Hyaluronic Acid Derivatives for Potential Treatment of Neovascular Ocular Diseases
No full textIn this work, new micellar systems able to cross corneal barrier and to improve the permeation of imatinib free base were prepared and characterized. HA-EDA-C16, HA-EDA-C16−PEG, and HA-EDA-C16−CRN micelles were synthesized starting from hyaluronic acid (HA), ethylenediamine (EDA), hexadecyl chains (C16), polyethylene glycol (PEG), or L-carnitine (CRN). These nanocarriers showed optimal particle size and mucoadhesive properties. Imatinibloaded micelles were able to interact with corneal barrier and to promote imatinib transcorneal permeation and penetration. In addition, a study was conducted to understand the in vitro imatinib inhibitory effect on a choroidal neovascularization process. Imatinib released from polymeric micelles was able to inhibit endothelial cell sprouting and to promote cell tube disruption
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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