1,720,993 research outputs found
Recenti applicazioni della tecnologia spray congealing: produzione di sistemi microparticellari per il miglioramento delle proprietà biofarmaceutiche di APIs BCS classe II.
No full textTra le numerose strategie tecnologiche che possono essere utilizzate per migliorare le proprietà biofarmaceutiche di molecole appartenenti alla classe II del Biopharmaceutic Classification System (BCS), negli ultimi anni si è assistito ad un crescente interesse per l’impiego della tecnologia spray congealing. Brevemente, la tecnologia spray congealing (anche conosciuta come spray chilling o spray cooling) si basa sull’atomizzazione di un fluido costituito da un eccipiente bassofondente (< 90 °C) allo stato fuso in cui è disperso o disciolto un farmaco. L’atomizzazione porta alla formazione di gocce che solidificano per raffreddamento durante la caduta, portando alla formazione di microparticelle. E’ un processo veloce, one-step e solvent-free, potenzialmente adatto per il continuous manufacturing.
Da anni il mio gruppo di ricerca studia le applicazioni in campo farmaceutico e nutraceutico di questa tecnologia. Ricerche precedenti hanno evidenziato che, studiando opportunamente la formulazione, lo spray congealing permette di produrre microparticelle in grado di controllare il rilascio di farmaci, mascherare sapori sgradevoli, proteggere dalla degradazione sostanze attive o, infine, aumentare la solubilità e/o la velocità di dissoluzione di molecole.
In questa comunicazione verranno presentati recenti sviluppi ottenuti impiegando un nuovo eccipiente (Gelucire 48/16), testando come APIs modello alcune molecole appartenenti alla classe II BCS con caratteristiche chimico-fisiche diverse (punto di fusione, pKa, ecc). I sistemi microparticellari prodotti sono stati caratterizzati per quanto riguarda le dimensioni, la morfologia (SEM), l’efficienza di incapsulazione e le proprietà dello stato solido (analisi DSC, XRD, FT-IR). Inoltre è stata valutata la solubilità dei farmaci e sono stati effettuati tests di dissoluzione a diversi pH. Infine sono stati eseguiti studi di stabilità. Tutti i sistemi microparticellari ottenuti hanno forma regolare e sferica e dimensioni medie intorno ai 200 μm (molto scorrevoli ed adatti alla somministrazione orale). L’efficienza di incapsulazione è sempre superiore al 95%. I tests in vitro hanno evidenziato per tutti i farmaci esaminati un significativo aumento della loro solubilità in acqua e della velocità di dissoluzione. Dati preliminari (6 mesi) suggeriscono la stabilità dei sistemi in condizioni normali.
I risultati ottenuti hanno confermato la potenzialità della tecnologia spray congealing per migliorare significativamente la solubilità e la velocità di dissoluzione di molecole BCS classe II
Polymer films comprising material secreted by gastropods
No full textThe present invention refers to a film, comprising at least one polymer and a material
secreted by a gastropod, in particular snail slime. The present invention also relates to a
5 procedure for the preparation and to uses of such film, in particular medical and cosmetic
uses, including veterinary uses. Further objects of the present invention include kits, films
for the storage and/or packaging of food, patches, masks and similar cosmetic products
comprising such film
FILM POLIMERICI COMPRENDENTI MATERIALE SECRETO DA GASTEROPODI
No full textLa presente invenzione si riferisce ad una pellicola o film, comprendente un polimero ed un materiale secreto da un gasteropode, in particolare bava di lumaca. La presente invenzione riguarda inoltre il procedimento di preparazione e gli usi, in particolare gli usi medici e gli usi cosmetici, anche veterinari, di tale composizione. Sono altresì oggetto della presente invenzione kit, pellicole per la conservazione e/o il confezionamento di cibi, cerotti, maschere e prodotti cosmetici simili comprendenti tale composizione
CHAPTER 3 - Nanomaterials for oral drug administration
No full textIn the last decade, a wide variety of oral nano-scaled drug delivery systems have been developed. This book chapter first gives a background on the challenges associated with the design of oral drug formulations, in relation to the well-known barriers presented by the gastrointestinal tract. Then, the most common nanomaterials used for oral formulations, which are classified as nanocrystals and nanosuspensions, polymeric, lipid and inorganic-based nanocarriers are described, plus a view on the most advanced nanomaterials, such as hybrid, protein and stimuli-responsive nanocarriers. Specifically, the properties, advantages and disadvantages of the different nanomaterials are reported. The design aspects of nanosystems for the targeting of specific gastrointestinal regions are also highlighted. Finally, critical considerations on the approaches to convert nanocarriers into final dosage forms suitable for oral administration, which are crucial to make these nanocarriers clinically and commercially available, are provided
Multi-composite system for the delivery of alendronate to bone tissue
No full textBakground
The bisphosphonate (BPs) class drug, is widely employed for the treatment of a variety of bone disorders. In this work Sodium
Alendronate (AL) was utilised as model Bisphosphonate drug. AL is often administered orally or via injection showing many side
effects. Recently different release approaches have been evaluated in order to targeted AL delivery to bone. In particular calcium
phosphate cements (CPCs) have been investigated as potential carries of BPs [1, 2]. The CPCs are bioactive and biodegradable
grafting materials made of powders of suitable composition which, when mixed with a liquid phase, give a modulable paste which
stiffens during the setting reaction and sets as primarily calcium-deficient hydroxyapatite. Unfortunately, the loading of AL interferes
with the conversion of pristine powders (like alfa-tricalcium phosphate, alfa-TCP) into hydroxyapatite, increasing the setting times
and worsening the mechanical properties. Therefore, the amount of AL that can be directly loaded is limited (1.8 mg / g) [1, 2].
Consequently, the drug encapsulation might overcome this drawback.
The aim of this work was to develop an innovative drug delivery system potentially useful for the delivery of AL to bone tissue. In
particular, we propose the use of Solid Lipid Microparticles (MPs), up to now mainly used for oral and topical drug delivery, as
carrier for AL, due to the favourable biocompatibility and lower toxicity of the lipids compared with many polymers. Thus a multicomposite
delivery platform consisted of a biomimetic-tricalcium phosphategelatin cement (CPCs) enriched with alendronate-loaded
MPs (MPs-AL) was developed.
Main results
For the preparation of the MPs, the spray congealing technology was employed [3]. In particular six different excipient were
considered: Stearic acid, Stearyl alcohol, Cutina® HR, Precirol® ATO 5 and Tristearin. In order to screen the effect of types,
dimensions and amount of unloaded MPs on the CPCs most important mechanical properties a Design of Experiment (DoE) was
employed. Then, MPs loaded with 10 % w/w of AL were produced using the different carriers. All MPs-AL exhibited a spherical
shape, encapsulation efficiency higher than 90% and prevalent particle size ranging from 100-150 micron. Solid state
characterization by means of DSC, HSM and X-ray powder diffraction demonstrated that encapsulation of the drug into MPs did not
alter its crystal structure. MPs-AL addition to the cement provoked a modest lengthening of the setting times and of the hardening
reaction leading to the complete transformation of alfa-TCP into calcium-deficient hydroxyapatite, without significantly affect the
cement mechanical properties. Then MPs loaded with different concentration of AL (10%, 20% and 30%) were embedded into the
CPC. The in vitro AL release studies from the multi-composite system (carried out in PB buffers at pH 7.4 at 37°C) showed that all
the system allowed a controlled release of the drug over time.
Therefore the results of this study demonstrated that it was possible to increase the amount of AL into the CPCs up to 10 time
compared to the value previously reported [1,2]. Moreover, the use of MPs as carriers to enrich bone cement formulation with AL
was a successful strategy to develop a system for the controlled local delivery of the drug.
Future and prospective
To value the effect of the AL release from CPCs-MPs system on cellular proliferation and differentiation, in vitro studies using
osteoblasts and osteoclasts cell cultures are in progress.
The obtain results suggest that this designed composite system could be useful for the delivery of other drugs (i.e. antibiotic, antiinflammatory
agents and anticancer drugs) to bone tissue
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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