Search results for "HYDROGELS"
showing 9 items of 299 documents
Formulation of Different Chitosan Hydrogels for Cartilage Tissue Repair
2014
Different formulations of Chitosan/sulphate and Chitosan/PEGDE were produced by physical and chemical reticulation to obtain hydrogels with better physiochemical properties. The hydrogels were analyzed – in terms of their non-toxicity, proliferative, differentiative, inflammatory and immunology responses. Commercial grade Chitosan (Sigma) was solubilized and purified by progressive filtrations. Then, the polymer was freeze-dried in a water soluble cationic form. A physical hydrogel was prepared by mixing a 3 % w/w water solution of the a.m. polymer with different stoichiometric ratios of (SO4=) 1/0.5;1/0.75;1/1 respectively. The hydrogels were cross-linked in multiwells. The chemical hydrog…
New hydrogel matrices containing an anti-inflammatory agent. Evaluation of in vitro release and photoprotective activity.
2002
In the present work. the preparation and characterization of hydrogels based on alpha,beta-polyaspartylhydrazide (PAHy) chemically crosslinked with ethyleneglycol diglycidylether (EGDGE) containing Tolmetin sodium salt, are reported. In particular, these samples have been prepared both as water swellable microparticles and as gels at two different crosslinking degrees. The incorporation of Tolmetin sodium salt in PAHy-EGDGE microparticles has been performed after the crosslinking reaction by a soaking procedure or during the formation of the network. The influence of drug loading procedure on Tolmetin release has been evaluated by performing in vitro release study in simulated gastrointesti…
Medicated hydrogels of hyaluronic acid derivatives for use in orthopedic field.
2013
Physical hydrogels have been obtained from hyaluronic acid derivatized with polylactic acid in the presence or in the absence of polyethylene glycol chains. They have been extemporarily loaded with antibacterial agents, such as vancomycin and tobramycin. These medicated hydrogels have been used to coat titanium disks (chosen as simple model of orthopedic prosthesis) and in vitro studies in simulated physiological fluid have been performed as a function of time and for different drug loading and polymer concentration values. Sterilization process performed on the hydrogels does not change their rheological behavior and release properties as well as the chemical structure of starting copolyme…
Impact of single-dose application of TGF-β, copper peptide, stanozolol and ascorbic acid in hydrogel on midline laparatomy wound healing in a diabeti…
2012
Despite numerous advances and improvements in surgical techniques the incidence of incisional hernias after laparotomy remains high. The aim of this study was to investigate possible effects of single application of ascorbic acid, stanozolol, a synthetic anabolic steroid, copper peptide and transforming growth factor-β (TGF-β) on laparotomy wound healing in an incisional wound model in diabetic mice. After diabetes induction with streptozotozin in Balb-c mice, midline laparatomies were carried out. Closure of the linea alba was followed by single-dose application of the agents dissolved in a hydrogel before skin closure. The functional outcome was assessed in terms of maximum tensile streng…
A hyaluronic acid/cyclodextrin based injectable hydrogel for local doxorubicin delivery to solid tumors
2020
Localized delivery of anticancer drugs is often the most useful therapeutic approach for the treatment of solid tumors. The use of injectable polymeric systems that maximize drug concentration in the proximal area of the tumor represents an extremely advantageous therapeutic strategy. Here, the development of an injectable in situ forming hydrogel was accomplished by exploiting the azo-type Michael reaction between an amine derivative of hyaluronic and vinylsulfone functionalized -cyclodextrins complexing doxorubicin. This injectable system can be easily prepared and administered with timelines compatible with normal operating room procedures, as demonstrated by rheological tests. In vitro…
Periodically nanostructured hydrogels for ethanol vapors sensing
2013
Chemical sensing using optics has been under extensive research all over the world during last decades and many optical chemical sensors are nowadays finding increasing applications in industry, environmental monitoring, medicine, biomedicine and chemical analysis. These optical sensors can be based on various optical principles, such as absorbance, reflectance or transmittance, luminescence and fluorescence, covering different regions of the spectrum (UV, visible, IR, NIR). Optical chemical sensors have several advantages over conventional electricity-based sensors, in terms of selectivity, immunity to electromagnetic interference, higher sensitivity, and they are also relatively inexpensi…
Feedback and Communication in Active Hydrogel Spheres with pH Fronts: Facile Approaches to Grow Soft Hydrogel Structures
2021
Abstract Compartmentalized reaction networks regulating signal processing, communication and pattern formation are central to living systems. Towards achieving life‐like materials, we compartmentalized urea‐urease and more complex urea‐urease/ester‐esterase pH‐feedback reaction networks into hydrogel spheres and investigate how fuel‐driven pH fronts can be sent out from these spheres and regulated by internal reaction networks. Membrane characteristics are installed by covering urease spheres with responsive hydrogel shells. We then encapsulate the two networks (urea‐urease and ester‐esterase) separately into different hydrogel spheres to devise communication, pattern formation and attracti…
PHOTOCROSSLINKING OF DEXTRAN AND POLYASPARTAMIDE DERIVATIVES: A COMBINATION SUITABLE FOR COLON- SPECIFIC DRUG DELIVERY.
2007
The aim of this study was to prepare and characterize novel hydrogels with polysaccharide–polyaminoacid structure, able to undergo an enzymatic hydrolysis in the colon and potentially useful for treating inflammatory bowel diseases (IBD). Starting materials were methacrylated dextran (DEX-MA) and methacrylated α,β-poly(N-2-hydroxyethyl)-DL-aspartamide (PHM). These polymers were photocrosslinked by exposure of their aqueous solutions at 313 nm without photoinitiators. Different samples, shaped as microparticles, were obtained as a function of polymer concentration and irradiation time. FT-IR analysis confirmed the occurrence of a co-crosslinking between DEX-MA and PHM in all experimental con…