Novel pH-sensitive chitosan hydrogels: swelling behavior and states of water

Qu, Xin; Wirsén, Anders; Albertsson, Ann‐Christine

doi:10.1016/s0032-3861(99)00685-0

Cited by 353 publications

(192 citation statements)

References 29 publications

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“…Three types of water are known to be present in the hydrogels and are referred to as nonfreezing bound water, intermediate freezing water and free freezing water [17,18]. Nonfreezing bound water refers to immobilized water molecules which are bound to the hydrophilic sites of the polymer chains and shows no melting peak.…”

Section: Resultsmentioning

confidence: 99%

Characterization of Genipin Crosslinked Hydrogels Composed of Chitosan and Partially Hydrolyzed Poly(vinyl alcohol)

2007

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Chitosan and 80 % hydrolyzed poly(vinyl alcohol) (PVA) were used to prepare semi-interpenetrating networks of varying ratios of the constituents. The hydrogels were crosslinked using genipin, a naturally occurring nontoxic crosslinking agent. The swelling behavior of these hydrogels was studied in deionized water at 25, 35 and 45 o C and in media of different pH at 25 o C. The swelling behavior of the gels was found to be dependent on temperature, pH of the medium and the amount of PVA present in the gel. States of water in the hydrogels swollen at 25 o C and pH 7 were determined using Differential Scanning Calorimetry (DSC). The amount of freezing water in the swollen hydrogels increased whereas the amount of nonfreezing bound water decreased with the increase in PVA concentration in the gels. The gelation behaviour of the pregel solutions were also studied.

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Section: Resultsmentioning

confidence: 99%

Characterization of Genipin Crosslinked Hydrogels Composed of Chitosan and Partially Hydrolyzed Poly(vinyl alcohol)

2007

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“…1). Responsive hydrogels, i.e., hydrophilic polymers embedded and cross-linked into hydrophilic structures [4], can respond to a broad range of stimuli, e.g., pH [5][6][7][8][9][10][11][12][13], temperature [14,15], individual molecules (chemically driven) [16][17][18][19], shear stress [20][21][22][23][24][25], etc., that trigger a change of material properties. In pHinduced responses, hydrogel swelling and deswelling occurs when polymers are ionized by the dynamically changing environmental pH [5].…”

Section: Flows In Active Porous Mediamentioning

confidence: 99%

Transient flows in active porous media

Kosmidis

Jensen

2017

Phys. Rev. E

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Stimuli-responsive materials that modify their shape in response to changes in environmental conditions-such as solute concentration, temperature, pH, and stress-are widespread in nature and technology. Applications include micro-and nanoporous materials used in filtration and flow control. The physiochemical mechanisms that induce internal volume modifications have been widely studied. The coupling between induced volume changes and solute transport through porous materials, however, is not well understood. Here, we consider advective and diffusive transport through a small channel linking two large reservoirs. A section of stimulus-responsive material regulates the channel permeability, which is a function of the local solute concentration. We derive an exact solution to the coupled transport problem and demonstrate the existence of a flow regime in which the steady state is reached via a damped oscillation around the equilibrium concentration value. Finally, the feasibility of an experimental observation of the phenomena is discussed.

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“…The swelling index of medicated mucoadhesive films was determined using two aqueous vehicles; namely, distilled water and simulated saliva solution (2.38g NaR 2RHPOR4R, 0.19g KHR 2RPOR4R and 8g NaCl/liter of distilled water adjusted with phosphoric acid to pH 6.8±0.05) [16]. Films (1x1 cm) were weighed alone and placed on a pre-weighed wire mesh (49 openings/cm 2 The Swelling Index was calculated using the formula [17][18][19].…”

Section: Water Uptake Of the Filmsmentioning

confidence: 99%

Chitosan Mucoadhesive Buccal Films: Effect of Different Casting Solvents on Their Physicochemical Properties

Abouhussein

El-Bary

Shalaby

et al. 2016

Int J Pharm Pharm Sci

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Objective: The aim of this work is to investigate the influence of different casting solvents on the physicochemical properties of cetylpyridinium chloride (CPC) chitosan mucoadhesive buccal films.Methods: Screening formulations were prepared by casting solvent technique using organic acids; 1% acetic acid (AA), 1% lactic acid (LA) and inorganic acid; 0.1N HCl (FS1-FS3). Then, 2P 1 P X3P 1 P factorial design study was done using 2 factors; solvent type (AA, LA, Mixture of 0.1N HCl and LA) and solvent concentration (AA and LA; 1%, 2% and mixture of 0.1N HCl: 1% LA; 2:1, 1:2). Films were evaluated for their physicochemical properties through, mechanical properties, mucoadhesion, in vitro release of CPC and antimicrobial activity. Results:The studied factors showed a significant effect on both mucoadhesion and tensile strength. Film casted from 0.1 N HCl was brittle and did not show any elasticity, so it was used in further studies mixed with LA to improve physicochemical properties of the prepared films. Films casted from LA showed swelling for an initial period of 15 min then no more swelling occurred while swelling of those casted from AA occurred throughout approximately 2 h. A film containing 2:1 HCl: LA (F5) dissolved in both media while 1:2 HCl: LA (F6) showed swelling properties. This was reflected on the in vitro release of CPC in which F5 gave higher % released (DER 300 min R54.37%) than the other formulations. Conclusion:Casting solvent was proved to have a significant effect on the physicochemical properties of chitosan CPC mucoadhesive films.

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Novel pH-sensitive chitosan hydrogels: swelling behavior and states of water

Cited by 353 publications

References 29 publications

Characterization of Genipin Crosslinked Hydrogels Composed of Chitosan and Partially Hydrolyzed Poly(vinyl alcohol)

Characterization of Genipin Crosslinked Hydrogels Composed of Chitosan and Partially Hydrolyzed Poly(vinyl alcohol)

Transient flows in active porous media

Chitosan Mucoadhesive Buccal Films: Effect of Different Casting Solvents on Their Physicochemical Properties

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