115 research outputs found
Synthetic Geopolymers for Controlled Delivery of Oxycodone: Adjustable and Nanostructured Porosity Enables Tunable and Sustained Drug Release
In this article we for the first time present a fully synthetic mesoporous geopolymer drug carrier for controlled release of opioids. Nanoparticulate precursor powders with different Al/Si-ratios were synthesized by a sol-gel route and used in the preparation of different geopolymers, which could be structurally tailored by adjusting the Al/Si-ratio and the curing temperatures. In particular, it was shown that the pore sizes of the geopolymers decreased with increasing Al/Si ratio and that completely mesoporous geopolymers could be produced from precursor particles with the Al/Si ratio 2∶1. The mesoporosity was shown to be associated with a sustained and linear in vitro release profile of the opioid oxycodone. A clinically relevant release period of about 12 h was obtained by adjusting the size of the pellets. The easily fabricated and tunable geopolymers presented in this study constitute a novel approach in the development of controlled release formulations, not only for opioids, but whenever the clinical indication is best treated with a constant supply of drugs and when the mechanical stability of the delivery vehicle is crucial
Zinc and silica are active components to efficiently treat in vitro simulated eroded dentin.
Objectives: Biomaterials for treating dentin hypersensitivity and dentin wear were
evaluated, to efficiently occlude the dentinal tubules and to increase dentin resistance to
abrasion. Materials and Methods: 24 dentin surfaces were treated with EDTA to expose
dentinal tubules, and were: 1) non-brushed, 2) brushed with distilled water, or with pastes
containing 3) Monetite, 4) Brushite, 5) Zn-Monetite, 6) Zn-Brushite, 7) Silica-Brushite
and 8) NovaMin®. Topography, nanomechanical and chemical analysis were assessed on
dentin surfaces (n=3) after artificial saliva immersion for 24 h, and after citric acid
challenge. 21 further dentin specimens were created to evaluate dentin permeability after
brushing, saliva storage and acid application (n=3). ANOVA, Student-Newman-Keuls
(p<0.05) and Student t-test (p<0.001) were used. Results: Particles containing major
proportion of silica attained intratubular occlusion by carbonate crystals (Raman
carbonate peak heights: 15.17 and 19.24 au; complex modulus: 110 and 140 GPa, at
intratubular dentin). When brushing with pastes containing higher proportion of silica or
zinc, phosphate calcium compounds were encountered into tubules and over dentin
surfaces (Raman intratubular phosphate peak heights: 49 to 70 au, and at the intertubular
dentin: 78 to 92). The formed carbonated apatite and calcium phosphate layer were
resistant to citric acid application. Zinc compounds drastically increased tubule occlusion,
decreased dentin permeability (up to 30%) and augmented mechanical properties at the
intertubular dentin (90-130 GPa), it was maintained after acid challenging. Conclusions:
Zinc-containing pastes occluded dentinal tubules and improved dentin mechanical
properties. Clinical Relevance: Using zinc as an active component to treat eroded dentin
is encouraged.Projects RTC-2014-1731-1 and MAT2014-52036-P
supported by the Ministry of Economy and Competitiveness and European Regional
Development Fund
Study by PIXE method of trace elements transferred from prostheses to sift tissues and organs
Quantification de phenomenes de transferts ioniques ou atomiques dans des materiaux implantes par la mise en oeuvre de methodes nucleaires
Proton beams used to study the behaviour of trace elements in gel formed around implant coated with bioactive glass
Etude Des Phenomenes Physiques Dans La Transformation Du Corail Implante 'in Vivo' Par Radioactivation Nucleaire Par Diffraction Des Rayons X Et Par Spectrometrie Infrarouge
Le corail biomateriau de comblement : evolution des proprietes biophysiques apres une implantation
Les hydroxyapatites hybrides et les bioverres;biomateriaux de revetement: evolution des proprietes biophysiques apres une implantation
Quantitative study of the coral transformations in vivo by several physical analytical methods
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