Double-phase hydrogel for buccal delivery of tramadol

2011 ◽  
Vol 38 (4) ◽  
pp. 468-483 ◽  
Author(s):  
Rabab Kamel ◽  
Azza Mahmoud ◽  
Gina El-Feky
Keyword(s):  
Buccal Delivery ◽  
Double Phase

Quantitative nano-characterization of heterogeneous catalysts

1995 ◽  
Vol 53 ◽  
pp. 398-399
Author(s):  
P.A. Crozier ◽  
M. Pan
Keyword(s):  
Heterogeneous Catalysts ◽  
Low Dose ◽  
Imaging Techniques ◽  
Structural Features ◽  
Catalyst Characterization ◽  
New Developments ◽  
Double Phase ◽  
Phase Systems ◽  
Dose Imaging

Heterogeneous catalysts can be of varying complexity ranging from single or double phase systems to complicated mixtures of metals and oxides with additives to help promote chemical reactions, extend the life of the catalysts, prevent poisoning etc. Although catalysis occurs on the surface of most systems, detailed descriptions of the microstructure and chemistry of catalysts can be helpful for developing an understanding of the mechanism by which a catalyst facilitates a reaction. Recent years have seen continued development and improvement of various TEM, STEM and AEM techniques for yielding information on the structure and chemistry of catalysts on the nanometer scale. Here we review some quantitative approaches to catalyst characterization that have resulted from new developments in instrumentation.HREM has been used to examine structural features of catalysts often by employing profile imaging techniques to study atomic details on the surface. Digital recording techniques employing slow-scan CCD cameras have facilitated the use of low-dose imaging in zeolite structure analysis and electron crystallography. Fig. la shows a low-dose image from SSZ-33 zeolite revealing the presence of a stacking fault.

Probing the Versatility of Shape-Persistent Tetraphenylmethane Dendrimers by Modification of the Skeleton

2019 ◽  
Author(s):  
Julio Ignacio Urzúa ◽  
Sandra Campana ◽  
Massimo Lazzari ◽  
Mercedes Torneiro
Keyword(s):  
Design Principle ◽  
Focal Point ◽  
Sonogashira Coupling ◽  
Terminal Alkyne ◽  
Double Phase ◽  
Rigid Rod ◽  
Convergent Approach ◽  
First And Second Generation ◽  
Oxidative Homocoupling ◽  
Hypercrosslinked Polymers

Tetraphenylmethane has emerged as a recurrent building block for advanced porous materials such as COFs, PAFs and hypercrosslinked polymers. Guided by a similar design principle, we have previously synthesized shape-persistent dendrimers with tetraphenylmethane nodes and ethynylene linkers. Here we report the generality of our approach by describing new dendritic architectures built from tetraphenylmethane. First, we prepared expanded dendrimers where the tetrahedral units are bonded through larger rigid rod spacers. Among the different synthetic strategies tested, the convergent route, with alternating steps of Pd-catalyzed Sonogashira coupling and alkyne activation by removal of TMS masking groups, efficiently afforded the first- and second-generation dendrimers. A second type of compounds having a linear diyne at the core is also described. The dendrimers of generations 1-2 were also synthesized by a convergent approach, with the diyne being assembled in the last step of the synthesis by a Glaser oxidative homocoupling of the corresponding dendrons bearing a terminal alkyne at the focal point. A third-generation dendrimer was also successfully prepared by a double-phase strategy.<br>

Differentiation of Tuberculous and Pyogenic Spondylitis Using Double Phase F-18 FDG PET

2008 ◽  
Vol 2 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Jung Sub Lee ◽  
Seong-Jang Kim ◽  
Kuen Tak Suh ◽  
In-Ju Kim ◽  
Yong-Ki Kim
Keyword(s):  
Fdg Pet ◽  
Pyogenic Spondylitis ◽  
Double Phase

Development, Characterization and Optimization of Mucoadhesive Tablet for Buccal Delivery of Domperidone

2019 ◽  
Vol 9 (1) ◽  
pp. 37-49
Author(s):  
Jagdale Sachin ◽  
Panbude Aishwarya ◽  
Navasare Priya
Keyword(s):  
Drug Release ◽  
Factorial Design ◽  
Research Work ◽  
Wet Granulation ◽  
Buccal Delivery ◽  
Scanning Calorimetry ◽  
Mucoadhesive Polymers ◽  
First Pass Metabolism ◽  
First Pass ◽  
Pass Metabolism

Background and Objective: Upon oral administration domeperidone is rapidly absorbed, but subjected to the first pass effect which lowers systemic bioavailability to 15%. Mucoadhesive tablet can remain attached to buccal mucosa and becomes capable of bypassing hepatic first-pass metabolism to improve absorption directly into systemic circulation. The present research work was carried with an aim to develop, evaluate and optimize mucoadhesive tablet containing domperidone (DOME) for buccal delivery using different bio-adhesive polymeric combinations. </P><P> Methods: The buccal tablets were formulated by wet granulation method using isopropyl alcohol. The preliminary formulations were prepared using combinations of HPMC K4, HPMC K15, HPMC K100, HPMC E5 as mucoadhesive polymers. 32 full factorial design was applied to determine the effect of independent variables like concentration of mucoadhesive polymers (HPMC K15 and HPMC K100) over dependent variables like mucoadhesive properties (swelling index, bioadhesive strength and in vitro drug release). The prepared mucoadhesive tablets were evaluated for their tablet properties and mucoadhesive properties. The interactions between drug and polymers were studied by Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). </P><P> Results: All formulations of factorial design showed satisfactory physicochemical, mechanical and bioadhesive characteristics. The formulation F9 exhibited maximum cumulative drug release, mucoadhesive strength and swelling index. Conclusion: The developed buccal tablet of domperidone might prove alternative to bypass the hepatic first pass metabolism and to avoid degradation which in turn may result in reducing the frequency of administration. Thus, mucoadhesive tablet of domeperidone may become viable alternative overcoming the side effects; achieving greater therapeutic effectiveness and improving the patient compliance.

scholarly journals Microstructure, Grain Growth and Hardness of Nanostructured Ferritic ODS Steel Powder during Annealing

2021 ◽  
Author(s):  
Krzysztof Nowik ◽  
Zbigniew Oksiuta
Keyword(s):  
Dislocation Density ◽  
Size Distribution ◽  
Hot Isostatic Pressing ◽  
Domain Size ◽  
Oxide Dispersion Strengthened ◽  
Alloy Formation ◽  
Nanocrystalline State ◽  
Ferritic Alloy ◽  
Ods Steel ◽  
Double Phase

AbstractNanocrystalline oxide-dispersion strengthened ferritic alloy formation and its annealing behavior were examined through modern X-ray diffraction pattern analysis and supplemented by microhardness and microscopic measurements. The basic microstructure features, with particular emphasis on evolution of domain size distribution and defect content during mechanical and thermal treatment, were quantified via the whole powder pattern modeling approach. The microstructure of the powdered alloy, formed during mechanical alloying, evolved toward nanocrystalline state consisting of narrow dispersion of very fine crystallites with substantial dislocation density, which exhibited relatively high stability against elevated temperature. It was shown that crystallite size is seriously sustained by the grain-boundary strain, therefore coarsening of grains begins only after the density of dislocations drops below certain level. Obtaining correct results for the annealing-related data at specific temperature range required the incorporation of the “double-phase” model, indicating possible bimodal domain size distribution. The dislocation density and grain size were found not to be remarkably affected after consolidation by hot isostatic pressing.

scholarly journals Symmetry and monotonicity of singular solutions of double phase problems

2021 ◽  
Vol 280 ◽  
pp. 435-463
Author(s):  
Stefano Biagi ◽  
Francesco Esposito ◽  
Eugenio Vecchi
Keyword(s):  
Singular Solutions ◽  
Double Phase

scholarly journals Solutions for parametric double phase Robin problems

2021 ◽  
Vol 121 (2) ◽  
pp. 159-170 ◽  
Author(s):  
Nikolaos S. Papageorgiou ◽  
Calogero Vetro ◽  
Francesca Vetro
Keyword(s):  
Boundary Condition ◽  
Existence Theorems ◽  
Robin Boundary Condition ◽  
Phase Problem ◽  
Double Phase ◽  
Robin Boundary ◽  
Double Phase Problem

We consider a parametric double phase problem with Robin boundary condition. We prove two existence theorems. In the first the reaction is ( p − 1 )-superlinear and the solutions produced are asymptotically big as λ → 0 + . In the second the conditions on the reaction are essentially local at zero and the solutions produced are asymptotically small as λ → 0 + .

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