Preparation of low-molecular-weight chitosan using phosphoric acid

Hasegawa, M.; Isogai, Akira; Onabe, Fumihiko

doi:10.1016/0144-8617(93)90100-i

Cited by 100 publications

(45 citation statements)

References 18 publications

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“…The mentioned hydrolysis effects usually take several weeks to proceed significantly. [17] In the present approach, chitinous materials were dissolved in warm concentrated phosphoric acid (85%, 60 8C), and A 210 was used to determine the extent of deacetylation. Sonication was performed to accelerate the dissolution process.…”

Section: Resultsmentioning

confidence: 99%

Spectrophotometric Determination of Deacetylation Degree of Chitinous Materials Dissolved in Phosphoric Acid

Hsiao

Tsai

Chen

et al. 2004

Macromolecular Bioscience

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A simple spectrophotometric method is proposed for determining deacetylation degrees (DD) of chitinous materials using phosphoric acid as the UV-transparent solvent system. Calibrating by the extinction coefficients (A(210)) of D-glucosamine and N-acetyl-D-glucosamine, DD values (24-88%) were computed numerically. The results correlated well (R(2) = 0.9805, n = 50) with those obtained by solid-state (13)C NMR. Comparison of the results obtained by the proposed UV method and solid-state (13)C NMR.

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Section: Resultsmentioning

confidence: 99%

Spectrophotometric Determination of Deacetylation Degree of Chitinous Materials Dissolved in Phosphoric Acid

Hsiao

Tsai

Chen

et al. 2004

Macromolecular Bioscience

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“…(Chitosan was first degraded according to published procedure [43] to render it water soluble before dissolution in water.) The reported values are the mean values of three measurements.…”

Section: Full Papermentioning

confidence: 99%

Cytocompatible Hydrogels Based on Photocrosslinkable Methacrylated O‐Carboxymethylchitosan with Tunable Charge: Synthesis and Characterization

Poon

Zhu

Jin

et al. 2007

Adv Funct Materials

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Ionic hydrogels are attractive for the protection, delivery and controlled release of charged biomacromolecules such as proteins, growth factors or DNA. We have prepared and characterized a series of photocrosslinked anionic hydrogels based on water soluble methacrylated (MA) O‐carboxymethylchitosan (OCMCS) and polyethylene glycol (PEG) diacrylate. OCMCS samples with varying degree of substitution of carboxymethyl group ranging from 0.69 to 1.86 were prepared by reacting native chitosan with different amounts of monochloroacetic acid. The OCMCS products demonstrated differences in solubility, zeta potential (–52.7 to –12.8 mV) and thermal decomposition temperature (260 to 283 °C). The OCMCS products were then reacted with glycidyl methacrylate to make ultra‐violet (UV) crosslinkable OCMCS‐MAs which were blended with PEG diacrylate, a photoinitiator and water and successfully photocrosslinked to create OCMCS‐MA/PEG hydrogels. Water uptake of the hydrogels varied between 226 % to 358 % and the porous structures of the prepared OCMCS‐MA/PEG hydrogels could be modulated by the degree of methacrylation. All the OCMCS‐MA/PEG hydrogel substrates similarly supported attachment and proliferation of Smooth Muscle Cells (SMCs). The in vitro biodegradation of these hydrogels, in the presence of SMCs, could be controlled by the degree of methacrylation; weight loss after 9‐week was (15±1) % and (19±2) % using OCMCS 4‐MA (12.7 % MA) and OCMCS 1‐MA (4.6 % MA), respectively. In addition, the hydrogel based on the most anionic OCMCS 1 showed higher adsorption of basic TGF‐β1 than similarly modified ‐agarose, ‐dextran, and ‐chondroitin sulfate hydrogels.

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“…In addition, two types of chitosan oligomer with DP 7.3 and 16.8 were prepared also by homogeneous hydrolysis of chitosan in 85% phosphoric acid at room temperature, but long reaction times of more than four weeks were required. 15 Fluorohydrolysis of chitosan in anhydrous hydrogen fluoride seemed to afford a more convenient route than conventional chemical depolymerization and produced products of DP of 2-10 in good yield. 16,17 However, this process also had practical limitations because of the necessity to perform an additional step for defluorination.…”

Section: Introductionmentioning

confidence: 99%

Salt-assisted acid hydrolysis of chitosan to oligomers under microwave irradiation

Xing

Liu

et al. 2005

Carbohydrate Research

108

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Preparation of low-molecular-weight chitosan using phosphoric acid

Cited by 100 publications

References 18 publications

Spectrophotometric Determination of Deacetylation Degree of Chitinous Materials Dissolved in Phosphoric Acid

Spectrophotometric Determination of Deacetylation Degree of Chitinous Materials Dissolved in Phosphoric Acid

Cytocompatible Hydrogels Based on Photocrosslinkable Methacrylated O‐Carboxymethylchitosan with Tunable Charge: Synthesis and Characterization

Salt-assisted acid hydrolysis of chitosan to oligomers under microwave irradiation

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