Structural change and swelling mechanism of pH-sensitive hydrogels based on chitosan andD,L-lactic acid

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

doi:10.1002/(sici)1097-4628(19991220)74:13<3186::aid-app22>3.0.co;2-y

Cited by 112 publications

(67 citation statements)

References 17 publications

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“…11,12 Information about molecular structure of complex mixtures can be obtained from Fourier transform infrared (FTIR) spectroscopic analysis. 13,14 The ease of sample preparation and operation, and nondestructive nature of analyses make FTIR attractive as a characterization technique to analyze gel formulations. Most organic molecules are IR sensitive.…”

Section: Introductionmentioning

confidence: 99%

Fourier transform infrared spectroscopy for the analysis of neutralizer-carbomer and surfactant-carbomer interactions in aqueous, hydroalcoholic, and anhydrous gel formulations

Islam

Rodrı́guez-Hornedo

Ciotti

et al. 2004

AAPS J

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The objective of the present study is to evaluate the polymersurfactant and polymer-neutralizer interactions in topical aqueous, anhydrous, and hydroalcoholic gel formulations using Fourier transform infrared (FTIR) spectroscopy. The gels were prepared by dispersing Carbomer (Carbopol 980) in water and ethanol for aqueous and anhydrous systems, respectively. Glycerol and propylene glycol were also added to ensure that the compositions of gels closely resembled those used in typical topical gel formulations. Comparisons of the spectra of Carbopol dispersions in aqueous, anhydrous, and hydroalcoholic systems, performed for the first time, show Carbopol-neutralizer and Carbopol-surfactant interactions vary depending on the nature of the solvents used for gel formation. Analysis of the spectra of aqueous gel formulations indicates significant presence of ionized carboxyl groups only at higher pH (~8.0). Drying of the aqueous gels causes a shift in the carbonyl stretch band toward higher energy, suggesting changes in polymer-neutralizer interaction. Anhydrous gels exhibit 2 different carbonyl stretch bands: the one at ~1653 cm -1 is related to the carboxyl group that is hydrogen bonded and is akin to hydrous gels; the second one at ~1717 cm -1 is indicative of free carbonyl groups. The carbonyl bands of dried gels appear at different energy levels than the solvated gels. This shift resulting from solvent evaporation, reported for the first time, indicates changes in hydrogen bond characteristics. The results show that FTIR can be a good technique compared with other more time-consuming means of analysis for topical formulations.

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Section: Introductionmentioning

confidence: 99%

Fourier transform infrared spectroscopy for the analysis of neutralizer-carbomer and surfactant-carbomer interactions in aqueous, hydroalcoholic, and anhydrous gel formulations

Islam

Rodrı́guez-Hornedo

Ciotti

et al. 2004

AAPS J

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“…A similar method has been used to coat polypropylene films with chitosan for improving dyeing behavior. 18 As shown previously, 16,17 aqueous solutions of chitosan and lactic acid can form hydrogels after heating. Chitosan is first dissolved in lactic acid solution to form chitosan lactate salt.…”

Section: Discussionmentioning

confidence: 99%

“…The coated films were dried in an oven at 80°C for 1 h. The thickness of the coated films was 31 ± 2 m. The synthesis and characterization of these chitosan hydrogels have been described previously. 16,17 Adsorption of PA by hydrogel layer …”

Section: Surface Modification Of Pet Balloons By Chitosan Hydrogelmentioning

confidence: 99%

Novel ?-emitting poly(ethylene terephthalate) surface modification

Weinberger

2000

J. Biomed. Mater. Res.

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Restenosis after percutaneous interventions in coronary and peripheral arteries leads to repeat procedures and surgery in a significant number of patients. We have previously demonstrated that irradiation of an arterial site using an endovascular source (brachytherapy) is highly effective in preventing the restenotic process. To this end, a novel beta radiation delivery system was developed, based on the adsorption of (32)P (o-phosphoric acid) by pH-sensitive chitosan hydrogel on a poly(ethylene terephthalate) (PET) balloon surface. The PET balloon surface was treated with oxygen plasma and coated with chitosan hydrogel. Covalent bonds, ionic bonds, and hydrogen bonds all contribute to the adhesion between chitosan hydrogel and PET. In the aqueous phosphoric acid (PA) solution, the -NH(2) groups of chitosan were protonated by PA and the adsorption of PA occurred at the same time. The effect of PA concentration and temperature on adsorption efficiency and kinetics were studied. More than 70% PA was adsorbed on the sample surface in 0.2 mM PA solution. The surface of samples was also investigated by attenuated total reflection-Fourier transform infrared spectroscopy and scanning electron microscopy. PET surface may be modified to carry high activity beta emitters; such materials may be useful in a therapeutic setting

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“…The volume change, and hence the degree of swelling of these hydrogels, with acidic or alkaline functionalities would depend on the degree of ionization of the functional groups. Poly(acrylic acid) [113,114], poly(methacrylic acid) [115][116][117], poly(ethylene imine) [118], poly(propylene imine) [119], chitosan [120][121][122][123], poly(L-lysine) [124,125], and poly (L-histidine) [126][127][128][129] are typical examples of pH sensitive polymeric hydrogels.…”

Section: Ph-sensitive Gelsmentioning

confidence: 99%

Smart polymeric gels: Redefining the limits of biomedical devices

Chaterji

Kwon

Park

2007

Progress in Polymer Science

560

364

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This review describes recent progresses in the development and applications of smart polymeric gels, especially in the context of biomedical devices. The review has been organized into three separate sections: defining the basis of smart properties in polymeric gels; describing representative stimuli to which these gels respond; and illustrating a sample application area, namely, microfluidics. One of the major limitations in the use of hydrogels in stimuli-responsive applications is the diffusion rate limited transduction of signals. This can be obviated by engineering interconnected pores in the polymer structure to form capillary networks in the matrix and by downscaling the size of hydrogels to significantly decrease diffusion paths. Reducing the lag time in the induction of smart responses can be highly useful in biomedical devices, such as sensors and actuators. This review also describes molecular imprinting techniques to fabricate hydrogels for specific molecular recognition of target analytes. Additionally, it describes the significant advances in bottom-up nanofabrication strategies, involving supramolecular chemistry. Learning to assemble supramolecular structures from nature has led to the rapid prototyping of functional supramolecular devices. In essence, the barriers in the current performance potential of biomedical devices can be lowered or removed by the rapid convergence of interdisciplinary technologies.

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Structural change and swelling mechanism of pH-sensitive hydrogels based on chitosan andD,L-lactic acid

Cited by 112 publications

References 17 publications

Fourier transform infrared spectroscopy for the analysis of neutralizer-carbomer and surfactant-carbomer interactions in aqueous, hydroalcoholic, and anhydrous gel formulations

Fourier transform infrared spectroscopy for the analysis of neutralizer-carbomer and surfactant-carbomer interactions in aqueous, hydroalcoholic, and anhydrous gel formulations

Novel ?-emitting poly(ethylene terephthalate) surface modification

Smart polymeric gels: Redefining the limits of biomedical devices

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