1,720,961 research outputs found
Preparation and in vitro characterization of novel pharmaceutical and cosmetic formulations consisting of urea-crosslinked hyaluronic acid
No full textHyaluronic acid (HA) is widely used in pharmaceutics, medicine and cosmetics, as it is biocompatible, biodegradable, mucoadhesive, moisturizer, viscoelastic and biologically active. To slow down its degradation rate and implement its bioactivity, HA can be chemically modified to develop a number of costumized and more performing derivatives tailored for different applications. The aim of the present PhD thesis was to investigate the possible pharmaceutical and dermatologic/cosmetic applications of the novel urea-crosslinked hyaluronic acid (HA‐CL). First, an in vitro preliminary study showed the safety and the re-ephitelialization efficacy of two prototypes of HA‐CL eye drops, which could represent promising treatments of keratoconjunctivitis sicca. Secondly, HA‐CL actual potentiality to prepare microspheres (MS) for sodium ascorbyl phosphate (SAP) dermal delivery was explored: a physico-chemical study displayed greater encapsulation efficiency and release properties for HA‐CL – SAP MS compared to native HA – SAP MS (reference formulation). Then, in an in vitro study on pulmonary Calu‐3 cells, the combination HA-CL ‐ SAP showed greater anti-inflammatory, antioxidant and wound healing properties compared to the combination native HA – SAP, the single HA‐CL, HA and SAP. This would support its possible use as co-adjuvant treatment of lung inflammatory diseases and encouraged the development and characterization of an inhalable dry powder formulation obtained by co-spray-drying of HA‐CL and SAP. Finally, a freeze-dried powder formulation of HA-CL and SAP was prepared and showed its suitability for nasal delivery in terms of physico-chemical properties, in vitro aerosolization performance and bioactivity on RPMI 2650 nasal cells and brushed nasal epithelial cells. Overall, all these research works proved that the novel HA-CL could have interesting applications, improved the knowdledge on this polymer and opened encouraging perspectives for future studies.L’acido ialuronico (AI) è ampiamente usato in ambito farmaceutico, medico e cosmetico, in quanto è biocompatibile, biodegradabile, mucoadesivo, idratante, viscoelastico e biologicamente attivo. Per rallentarne la velocità di degradazione ed implementarne la bioattività, si può modificare chimicamente l’AI, sviluppando così derivati più performanti e adatti a diverse applicazioni. Lo scopo della presente tesi di dottorato è stato studiare le possibili applicazioni farmaceutiche e dermatologiche/cosmetiche del nuovo acido ialuronico crosslinkato con urea (AI‐CL). Innanzitutto, uno studio preliminare in vitro ha mostato la sicurezza e l’attività riepitelizzante di due prototipi di gocce oculari di AI‐CL, che potrebbero rappresentare promettenti trattamenti per la cheratocongiuntivite secca. In secondo luogo, è stata esplorata la possibilità di preparare microsfere (MS) di AI‐CL per il rilascio dermico di sodio ascorbyl fosfato (SAF): uno studio fisico-chimico ha mostrato una più elevata efficienza di incapsulazione e migliori proprietà di rilascio per le MS di AI‐CL e SAF, rispetto alle MS di AI nativo e SAF (formulazione controllo). Successivamente, in uno studio in vitro su cellule polmonari Calu‐3, la combinazione AI‐CL – SAF ha mostato migliori proprietà antinfiammatorie, antiossidanti e cicatrizzanti rispetto alla combinazione AI – SAP, e ai singoli AI‐CL, AI e SAF. Questo supporterebbe il suo possibile utilizzo come trattamento coadiuvante per i disturbi infiammatori polmonari, e ha incoraggiato lo sviluppo e la caratterizzazione di una formulazione costituita da una polvere secca inalabile ottenuta per co-spray-drying di AI‐CL e SAF. Infine, è stata preparata un’altra formulazione a base di una polvere secca, ottenuta per liofilizzazione di AI‐CL e SAF; essa è risultata adatta per uso nasale in termini di proprietà fisico-chimiche, performance aerodinamica in vitro e bioattività su cellule nasali RPMI 2650 e su cellule nasali epiteliali primarie. Nel complesso, questi lavori sperimentali hanno mostrato che il nuovo AI‐CL può avere interessanti applicazioni, hanno ampliato le conoscenze relativamente all’AI‐CL e hanno aperto incoraggianti prospettive per studi futuri
L’Acido Ialuronico (AI) nei trattamenti estetici, una review critica
No full textDa sempre la chirurgia estetica ha rappresentato la soluzione più efficiente per combattere
i segni dell’invecchiamento, permettendo di correggere i difetti del viso e ridonare
lucentezza ed elasticità alla pelle. Quest’ultima, infatti, è soggetta a cambiamenti nel tempo
dovuti principalmente a fattori quali l’età, l’ambiente, le condizioni di vita, l’alimentazione,
lo stress, le radiazioni solari e le condizioni di microcircolo cutaneo. I risultati di tutti questi
fattori sono la perdita di elasticità e lucentezza della cute e la formazione di rughe e solchi
nelle aree del viso. Negli ultimi anni, tuttavia, l’avvento dei Dermal Fillers (DF) ha
rappresentato l’alternativa per eccellenza alla chirurgia estetica, permettendo di ottenere
ottimi risultati con una percentuale di rischi ed effetti collaterali notevolmente inferiore.
L’applicazione dei DF, infatti, può essere eseguita in ambito ambulatoriale, senza ricorrere
alla sala operatoria, ed è effettuata con aghi di diverse dimensioni che assicurano un
trattamento locale pressochè indolore. Tra i DF attualmente in commercio, quello più
utilizzato è l’Acido Ialuronico (AI) che, grazie alla sua alta biodegradabilità e
biocompatibilità, è perfettamente tollerato dall’organismo e permette una correzione precisa
e poco invasiva. Il grande vantaggio dell’AI, inoltre, è la sua reversibilità che permette di
correggere il suo uso improprio o eccessivo grazie alle ialuronidasi che, iniettate subito dopo
l’AI, ne degradano le molecole. Inizialmente estratto allo stato libero dalle creste del gallo,
l’AI è stato successivamente prodotto in laboratorio per via microbiologica fermentativa a
partire dai batteri Streptococcus Lancefield A e C, Streptococcus equi e zooepidemicus
mediante il cross-linking system che permette di ottenere un gel più resistente e duraturo nel
tempo. Vi sono attualmente in commercio diversi fillers a base di AI che differiscono per le
loro caratteristiche chimico-fisiche, nonché reologiche, quali l’elasticità, la viscosità e la
forza di estrusione. In base a queste stesse caratteristiche, ogni filler di AI è più indicato per
un particolare tipo di difetto e una specifica area del viso come, ad esempio, le rughe della
fronte, della glabella, i solchi nasolabiali e della marionetta. I fillers di AI ad oggi più
utilizzati sono: Restylane® e Perlane® (per rughe e solchi nasolabiali e volumizzazione
delle labbra), Hylaform® e Belotero® (per rughe e solchi di media e severa entità),
Captique® (per rughe di lieve entità), Juvéderm® (per rughe e difetti profondi) ed Elevess®
(per guance, fronte e labbra). L’utilizzo di questi fillers è considerato sicuro in quanto gli
effetti collaterali derivanti dal loro uso sono rari e di lieve entità, quali gonfiore, lividi,
eritema, arrossamento e prurito nella zona di iniezione, destinati comunque a svanire
nell’arco di poche ore.
I DF in medicina estetica sono in continuo sviluppo e sono previste molte nuove
formulazioni di AI attualmente in attesa di approvazione dalla FDA; nel 2014, infatti, il
numero totale di trattamenti estetici ha superato il milione e, di tali interventi, il 76% è
rappresentato da trattamenti con DF. Grazie alla loro elevata popolarità e all’alto grado di
soddisfazione dei pazienti, i DF hanno davanti a sé un brillante futuro come eccellenti
alternative alla chirurgia plastica, in grado di assicurare risultati notevoli e meno invasivi con
minimi effetti collaterali
Hyaluronic Acid Fillers in Soft Tissue Regeneration
No full textAbstractOver the last years, hyaluronic acid (HA) injectable dermal fillers (DFs) have become the most popular agents for soft tissue contouring and volumizing. HA fillers are characterized by most of the properties that an ideal DF should have, due to HA unique chemical-physical properties, biocompatibility, biodegradability, and versatility. Therefore, HA DFs have revolutionized the filler market with a high number of products, which differ in terms of HA source, cross-linkage (agent and degree), HA concentration, hardness, cohesivity, consistency, inclusion or lack of anesthetic, indication, and longevity of correction. The article first provides a general introduction to DF world, and an overview of the different materials is available for fillers. Second, it describes the characteristics and the peculiarities of HA fillers, their differences from the other available materials, and therefore the reasons at the base of their success. Moreover, an update regarding the main Food and Drug Administration (FDA) approved fillers is presented.</jats:p
Hyaluronic Acid in the Third Millennium
No full textSince its first isolation in 1934, hyaluronic acid (HA) has been studied across a variety of research areas. This unbranched glycosaminoglycan consisting of repeating disaccharide units of N-acetyl-d-glucosamine and d-glucuronic acid is almost ubiquitous in humans and in other vertebrates. HA is involved in many key processes, including cell signaling, wound reparation, tissue regeneration, morphogenesis, matrix organization and pathobiology, and has unique physico-chemical properties, such as biocompatibility, biodegradability, mucoadhesivity, hygroscopicity and viscoelasticity. For these reasons, exogenous HA has been investigated as a drug delivery system and treatment in cancer, ophthalmology, arthrology, pneumology, rhinology, urology, aesthetic medicine and cosmetics. To improve and customize its properties and applications, HA can be subjected to chemical modifications: conjugation and crosslinking. The present review gives an overview regarding HA, describing its history, physico-chemical, structural and hydrodynamic properties and biology (occurrence, biosynthesis (by hyaluronan synthases), degradation (by hyaluronidases and oxidative stress), roles, mechanisms of action and receptors). Furthermore, both conventional and recently emerging methods developed for the industrial production of HA and its chemical derivatization are presented. Finally, the medical, pharmaceutical and cosmetic applications of HA and its derivatives are reviewed, reporting examples of HA-based products that currently are on the market or are undergoing further investigations
Novel Artificial Tears Containing Cross-Linked Hyaluronic Acid: An In Vitro Re-Epithelialization Study
No full textDry eye syndrome is a common disease which can damage the corneal epithelium. It is treated with eye drops to stimulate tear production and hydrate the corneal surface. The most prescribed artificial tear remedies contain hyaluronic acid (HA), which enhances epithelial wound healing, improving tissue health. To the best of our knowledge, only a few recent studies have investigated cross-linked HA (HA-CL) in eye drops for human applications. This work consists in an in vitro evaluation of the re-epithelialization ability of two different preparations containing a recently synthetized HA cross-linked with urea: 0.02% (w/v) HA-CL (solution 1, S1), and 0.4% (w/v) HA-CL (solution 2, S2). The study was conducted on both 2D human corneal cells (HCEpiC) and 3D reconstructed tissues of human corneal epithelium (HCE). Viability by 3(4,5-dimethylthiazol-2)2,5-diphenyltetrazolium bromide (MTT) test, pro-inflammatory cytokine release (interleukin-8, IL-8) by ELISA, and morphology by hematoxylin and eosin (HE) staining were evaluated. In addition, to understand the molecular basis of the re-epithelialization properties, cyclin D1 levels were assessed by western blot. The results showed no cellular toxicity, a slight decrease in IL-8 release, and restoration of epithelium integrity when the wounded 3D model was treated with S1 and S2. In parallel, cyclin D1 levels increased in cells treated with both S1 and S2
Co-Spray-Dried Urea Cross-Linked Hyaluronic Acid and Sodium Ascorbyl Phosphate as Novel Inhalable Dry Powder Formulation
No full textThe pathogenesis and progression of several lung disorders is propagated by inflammatory and oxidative processes, which can be controlled by adjunctive inhaled therapies. The present study aimed to develop an inhalable dry powder formulation consisting of co-spray-dried urea-crosslinked hyaluronic acid and sodium ascorbyl phosphate (SD HA-CL-SAP), a novel combination which was recently shown to possess anti-inflammatory, antioxidant, and wound healing properties. Native HA and SAP were co-spray dried (SD HA-SAP) and evaluated as control formulation. Yield (Y%) and encapsulation efficiency (EE%) were 67.0 +/- 4.8% and 75.5 +/- 7.2% for SD HA-SAP, 70.0 +/- 1.5% and 66.5 +/- 5.7% for SD HA-CL-SAP, respectively. Both formulations were shown to be suitable for lung delivery in terms of morphology, particle size (median volumetric diameter similar to 3.4 mm), physical and thermal stability, in vitro aerosol performance - respirable fraction: 30.5 +/- 0.7% for SD HA-SAP and 35.3 +/- 0.3% for SD HA-CL-SAP. SAP release was investigated using Franz cells and air-interface Calu-3 cell model (>90% of SAP transported within 4 h). The innovative SD HA-CL-SAP formulation holds potential as inhalable dry powder for the treatment of inflammatory lung disorders. (c) 2019 American Pharmacists Association (R). Published by Elsevier Inc. All rights reserved
Herbal extracts, lichens and biomolecules as natural photo-protection alternatives to synthetic UV filters. A systematic review
No full textBesides the unquestionable positive effects of solar exposure for human health, UV rays have been widely investigated for toxicology aspects related to excessive UVB and UVA doses, which involve sunburns, skin aging, DNA skin damage and tumorigenesis. At present, synthetic and mineral sunscreens are used to protect against these damages but several natural molecules can provide UV protection, including also synergic effect or enhanced photo stability. Although a large number of herbal extracts and plant origin molecules can deserve potential applications, most of the study reported utilizes different method and different strategies of investigation, making thus difficult to understand the real versus claimed potential. This is possibly one of the reasons why, beside the large body of literature there are no officially approved natural commercial sun-filter but a consistent number of commercially available solar products (sunscreen) on the market that contain herbal derivatives. In this review we have evaluated the papers appeared in the last 15 years and we have critically collected the most significant data. Several databases, namely Scifinder, Pubmed, Google Scholar, ISI-Web of Science and Scopus, were used as literature sources; excluding patents and symposium or congress papers. Only articles in the English language have been selected. New formulation, new skin delivery systems, skin penetration enhancers and boosters are most likely the next frontier of investigation in order to better understand the role of whole herbal extracts in exerting their photo protective activity
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
- …
