Characterization of Rheological Property of Mucoadhesive Polymeric Sol-Gel in the Presence of Black Ginger Kaempferia parviflora Extract

2020 ◽  
Vol 859 ◽  
pp. 81-86
Author(s):  
Siriporn Taokaew ◽  
Nattanich Wattanaphraya ◽  
Worawut Kriangkrai

The local drug delivery based on mucoadhesion is an effective medical treatment. The mucoadhesive property relies on the formulated gel having optimized rheology. The addition of the drug also showed a major influence towards the sol-gel transition. In this study, compositional effect of Eudragit E100® base polymer, various mucoadhesive polymers, and the black ginger extract on the rheological property of the formulated sol-gel was assessed. It was found that gelling point and gel strength could be tuned mainly based on the concentration of Eudragit E100 limited at 40% w/w due to the viscosity. At Eudragit E100 of 30% w/w, 0.5% w/w herbal extract, and 1%w/w polyvinyl alcohol, the solution reached the gel point at 286 s (tan δ=1) with the gel strength of 1 kPa (G’=G”). For all the formulated sol-gels, the rheological property became better (faster gelling point with the gel strength varying from 100-700 kPa at low strain) a simulated saliva environment.

1989 ◽  
Vol 177 ◽  
Author(s):  
M. A. V. Axelos ◽  
M. Kolb

ABSTRACTRheological measurements have been performed on pectin-calcium systems close to the sol-gel transition. Two different experimental setups - steady state and oscillatory shear measurements - show scaling of the viscoelastic properties. The results of both types of measurements are consistent with each other and with scalar percolation theory.


2005 ◽  
Vol 480-481 ◽  
pp. 355-360
Author(s):  
Nopphawan Phonthammachai ◽  
Morakot Rumruangwong ◽  
Sirirat Jitkanka ◽  
Erdogan Gulari ◽  
Alexander M. Jamieson ◽  
...  

The viscoelastic behavior of different ceria gelling systems prepared through sol-gel transition were investigated by the rheological measurement. The gelation time was observed by the frequency independence of tand, and increased with increasing acid:alkoxide molar ratio. At the gel point, both storage and loss moduli (G’µ wn, G” µ wn)exhibited a power law dependence of applied frequency with n’ = n” = n. The viscoelastic exponents and gel strength parameter were dependent on the composition of system. The increase in HCl:alkoxide molar ratio increased the n value while decreased the S parameter.


2011 ◽  
Vol 399-401 ◽  
pp. 1326-1329
Author(s):  
Dong Ying Xu ◽  
Zheng Fu Liao ◽  
Hui Wang

Konjac glucomannan (KGM) has been widely used in pharmaceutical, chemical engineering, food industry, drug carrier delivery, etc. The sol-gel transition kinetics of KGM dilute solution was studied by steady fluorescence spectroscopy in this article. The results showed that the gel point of KGM solutions depend on the concentration of KGM, pH value and temperature. The sol-gel phase transition activation energy, ΔE, was calculated to be 83.1 kJ/mol based on first reaction kinetic model.


2016 ◽  
Vol 4 (Special-Issue-October) ◽  
pp. 18-25 ◽  
Author(s):  
A.E Labropoulos ◽  
T. H Varzakas

Many naturally-occuring gels exists in the biological systems such as foods. Because of their biodiversibily and delicate nature, their properties can be used by the food industry to achieve a variety of physicochemical functions. The gel utilized in this study, soy protein isolates (SPI) and concentrates (SPC), all have unique rheological properties which play an important role in their strength function of foods. The objective of this study is to gain insights as to how the rheological properties of these bio-gels are designed to control the gel-strength of these materials. The concentration dependence of dynamic moduli G’ and G” of soy protein isolates (SPI) and soy protein concentrates were studied in solutions prepared under different conditions. Three-level preliminary fractional experiments were undertaken to study effects of temperature, pH, and concentration on the gel-strength of these products. Protein concentration, pH and temperature appear to have an impact on the strength of these bio-gels. An investigation of the viscoelastic behavior of SPI solution at the sol-gel transition point was mainly considered by applying a rheological testing procedure. The data demonstrated a power law frequency dependence of the viscoelastic functions G΄(ω) and n*(ω) at the gel point. At low temperatures and high concentrations we get weaker gel-strengths than at high temperatures and low concentrations. Lowering the concentration and keeping the temperature constant seem to have little effect on the gel strength but points towards to becoming stronger gels.


2021 ◽  
Author(s):  
◽  
Rebecca Hudson

Characterisation of viscoelastic materials through exploitation of the frequency independent gel point (GP) can be used to study blood clotting anomalies. Information regarding the sol-gel transition can be obtained for gelling systems by employing small amplitude oscillatory shear (SAOS) measurements over a range of oscillatory shear frequencies. Analysis of the fractal dimension, , at the GP has previously been used as a biomarker for pathologies related to thromboembolic disease. This thesis investigates the potential adverse clotting characteristics induced by the presence of exhaust particulates using rheometric techniques. SAOS experiments conducted using a combined motor transducer (CMT) rheometer are susceptible to inertial artefacts at high frequencies, leading to potentially significant error in the reported GP. Herein, the development and evaluation of an enhanced rheometer inertia correction procedure (ERIC) is shown to allow valid GP data to be obtained post-acquisition at previously inaccessible frequencies. The potential impact of soot particulates on coagulation is likely to be small due to the weakly elastic gelling systems being studied, thus necessitating the use of the ERIC procedure to remove the presence of any inertial artefacts causing miscalculation of the GP. Fibrin gels were studied as model blood clots to assess the effects of the inclusion of soot particulates on the GP. The impact of the inclusion of increasing concentrations of soot solution on the GP proved inconclusive after the application of ERIC. However, in whole blood clots, the post-ERIC GP data indicated an increase in the density of the clot formed with increasing soot concentration, suggesting an elevated health risk as a possible result of interruption of the clotting cascade due to soot particulates.


2012 ◽  
Vol 66 (10) ◽  
Author(s):  
Ivana Chamradová ◽  
Lucy Vojtová ◽  
Lenka Michlovská ◽  
Petr Poláček ◽  
Josef Jančář

AbstractFunctionalised triblock copolymers based on poly((lactic acid)-co-(glycolic acid)) and poly(ethylene glycol) (PLGA-PEG-PLGA) further modified with 3-methylenetetrahydrofuran-2,5-dione (itaconic anhydride; ITA) exhibited sol-gel transition induced by increasing temperature. Rheological properties of a series of ITA/PLGA-PEG-PLGA/ITA copolymer concentrations (6–24 mass %) in deionised Milli-Q water were studied by both the test tube inverting method (TTIM) and rheometer. The gel stiffness increased with the polymer concentration shifting the gel point of the copolymer to the lower temperature. The present study demonstrates that each method describes a sol-gel transition, but the combined method gives comprehensive information about changes in colour, viscosity, elastic and loss moduli. Characterisation of such a gel is necessary for its further use, in order to determine whether the material is appropriate as an injectable biomedical hydrogel.


1990 ◽  
Vol 180 ◽  
Author(s):  
James E. Martin ◽  
Jess Wilcoxon

ABSTRACTNear the gel point, light scattering studies of silica sol-gels reveal fractal clusters whose size diverges as a power law, in accord with the predictions of percolation theory. More surprising is the appearance of a fractal time description of the dynamics of these clusters. This novel dynamics has recently been revealed by quasielastic light scattering from the density fluctuations that occur at the sol-gel transition. Since the relaxation of fluctuations in these branched polymer systems is self-similar, decay processes occur on all time scales (fractal time), and average decay times diverge. An interpretation of this observation will be presented that relies on a length-scale-dependent viscosity and the geometrical self-similarity of the sol-gel transition. The scattering theory is extended to the calculation of time- and frequency-dependent viscoelastic properties, as well as mechanical properties such as the shear modulus, steady state creep compliance, and viscosity. The viscoelastic predictions are found to be in good agreement with experimental data.


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