Characterisation of alginate gels using quasi-static and dynamic methods

Moresi, Mauro; Bruno, M.C.

doi:10.1016/j.jfoodeng.2007.02.040

Cited by 41 publications

(48 citation statements)

References 31 publications

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“…The liberated Ca +2 ion reacted with the carboxyl groups of CMXG in situ and thus cross-linked the free carboxyl group of CMXG. Similar ionic cross-link between Ca +2 ion and alginate (25,26), carboxymethyl guar (6,27), and pectin (11,28) have been reported. The cross-link restricts the mobility of the polymer chains and results in the formation of a true gel layer in contact with water around the MDT mean dissolution time, SD standard deviation tablet surface (29).…”

Section: Drug Releasesupporting

confidence: 75%

Development and Evaluation of Ca+ 2 Ion Cross-Linked Carboxymethyl Xanthan Gum Tablet Prepared by Wet Granulation Technique

Maity

2014

AAPS PharmSciTech

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Abstract. The objective of this work was to study the release behavior of prednisolone from calcium-crosslinked carboxymethyl xanthan gum (CMXG) tablets in dissolution medium having different pH values prevailing in the gastrointestinal lumen. Xanthan gum (XG) was derivatized to CMXG which was then cross-linked in situ with Ca +2 ion during wet massing step of tablet preparation. Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry studies did not show any drug-polymer interaction although the drug underwent solid-state transformation during compression as evident from X-ray diffraction analysis. In vitro release study demonstrated that increase in the amount of Ca +2 ion decreased the drug release, and beyond a certain amount, the drug release increased. While increase in both drug load and tablet crushing strength decreased the drug release, increase in exposure time in acid solution of pH 1.2 increased the overall release of the drug. The mechanism of drug release was nonFickian/anomalous. The results indicated that variation in the amount of Ca +2 ion can modulate the drug release from CMXG matrix tablets as needed.

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Section: Drug Releasesupporting

confidence: 75%

Development and Evaluation of Ca+ 2 Ion Cross-Linked Carboxymethyl Xanthan Gum Tablet Prepared by Wet Granulation Technique

Maity

2014

AAPS PharmSciTech

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“…For in situ gelation, negative normal stress with an approximate value of 500 Pa developed during the gelation process. This was likely due to the shrinkage of the sample during the crosslinking reaction between Ca 21 and alginate chains as the sol to gel transition takes place. 40 Such normal force was removed prior to the rheological investigations by manually reducing the gap between the plates (gap reduction is on the order of 0.5-1%).…”

Section: Resultsmentioning

confidence: 99%

“…Alginate stock solution with polymer concentration of 10 mg mL 21 was prepared by mixing alginate powder in deionized water using an overhead mixer (Troemner LLC) at 1000 rpm for 20 min. The desired amount of CaHPO 4 powder was introduced in the alginate stock solution and was then mixed for 5 min at 1000 rpm.…”

Section: Preparation Of Alginate Hydrogelsmentioning

confidence: 99%

“…The geometry inertia calibration was conducted with sand paper. Time sweep tests were conducted at a strain of 0.1% and frequency of 0.5 rad s 21 to capture the increase of shear modulus resulted from gelation. Gelation time was varied between 6 and 10 h depending on the Ca 21 concentration used.…”

Section: Preparation Of Alginate Hydrogelsmentioning

confidence: 99%

“…15 In presence of multivalent cations, such as Ca 21 18,19,37 Here, for rheological investigations, alginate hydrogels were prepared by in situ gelation technique with sand paper coated fixtures. As a result, the samples were strongly attached to the rheometer plates and the interfacial slippage during large-strain deformation was largely avoided.…”

mentioning

confidence: 99%

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Strain stiffening and negative normal stress in alginate hydrogels

Hashemnejad

Kundu

2016

J Polym Sci B Polym Phys

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Alginate hydrogels are polysaccharide biopolymer networks widely useful in biomedical and food applications. Here, we report nonlinear mechanical responses of ionically crosslinked alginate hydrogels captured using large amplitude oscillatory shear experiments. Gelation was performed in situ in a rheometer and the rheological investigations on these samples captured the strain-stiffening behavior for these gels as a function of oscillatory strain. In addition, negative normal stress was observed, which has not been reported earlier for any polysaccharide networks. The magnitude of negative normal stress increases with the applied strain amplitude and can exceed that of the shear stress at large-strain. Fitting a constitutive relationship to the stress-strain curves reveals that the mode of deformation involves stretching of the alginate chains and bending of both the chains and the junction zones. The contribution of bending increases near saturation of G blocks as Ca 21 concentration was increased. The results presented here provide an improved understanding of the deformation behavior of alginate hydrogels and such understanding can be extended to other crosslinked polysaccharide networks. V C 2016

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Behavior of alginate–gelatin blended gel with embedded macrovoids: Stress‐induced changes and the solute release characteristics

Banerjee

Ganguly

2020

J of Applied Polymer Sci

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Blending of gelatin to alginate promote cell–material interaction. However, the changes in diffusive and mechanical properties need to be ascertained. This study shows that the presence of two superposed polymer networks, where gelatin is not additionally crosslinked resulted in higher uptake and slower release of vitamin B12. In the presence of gelatin, the stress is found higher for the same level of compressive deformation, and the permeability of the pore fluid during expulsion under compressive stress is found significantly lower. Also, a large residual strain at the end of each cycle in case of cyclic compression is observed, when gelatin is present. A microfluidic device is used to introduce voids uniformly across the blended gel with an objective to increase compressibility, permeability (for faster equilibration of pore pressure), and uptake of bioactive species. The results showing lower permeability and higher uptake in the presence of gelatin are discussed.

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Characterisation of alginate gels using quasi-static and dynamic methods

Cited by 41 publications

References 31 publications

Development and Evaluation of Ca+ 2 Ion Cross-Linked Carboxymethyl Xanthan Gum Tablet Prepared by Wet Granulation Technique

Development and Evaluation of Ca+ 2 Ion Cross-Linked Carboxymethyl Xanthan Gum Tablet Prepared by Wet Granulation Technique

Strain stiffening and negative normal stress in alginate hydrogels

Behavior of alginate–gelatin blended gel with embedded macrovoids: Stress‐induced changes and the solute release characteristics

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