scholarly journals Extensively deacetylated high molecular weight chitosan from the multistep ultrasound-assisted deacetylation of beta-chitin

2016 ◽  
Vol 32 ◽  
pp. 79-85 ◽  
Author(s):  
Anderson Fiamingo ◽  
Jorge Augusto de Moura Delezuk ◽  
Stéphane Trombotto ◽  
Laurent David ◽  
Sergio Paulo Campana-Filho
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Ultrasound Assisted ◽  
High Molecular Weight Chitosan

scholarly journals Physicochemical and Antifungal Properties of Clotrimazole in Combination with High-Molecular Weight Chitosan as a Multifunctional Excipient

Marine Drugs ◽  
2020 ◽  
Vol 18 (12) ◽  
pp. 591
Author(s):  
Bożena Grimling ◽  
Bożena Karolewicz ◽  
Urszula Nawrot ◽  
Katarzyna Włodarczyk ◽  
Agata Górniak
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Weight Ratio ◽  
Scanning Calorimetry ◽  
Minimal Inhibitory Concentrations ◽  
Dissolution Tests ◽  
Effective Combination ◽  
The Impact ◽  
High Molecular Weight Chitosan

Chitosans represent a group of multifunctional drug excipients. Here, we aimed to estimate the impact of high-molecular weight chitosan on the physicochemical properties of clotrimazole–chitosan solid mixtures (CL–CH), prepared by grinding and kneading methods. We characterised these formulas by infrared spectroscopy, differential scanning calorimetry, and powder X-ray diffractometry, and performed in vitro clotrimazole dissolution tests. Additionally, we examined the antifungal activity of clotrimazole–chitosan mixtures against clinical Candida isolates under neutral and acid conditions. The synergistic effect of clotrimazole and chitosan S combinations was observed in tests carried out at pH 4 on Candida glabrata strains. The inhibition of C. glabrata growth reached at least 90%, regardless of the drug/excipient weight ratio, and even at half of the minimal inhibitory concentrations of clotrimazole. Our results demonstrate that clotrimazole and high-molecular weight chitosan could be an effective combination in a topical antifungal formulation, as chitosan acts synergistically with clotrimazole against non-albicans candida strains.

scholarly journals Catalytic Degradation of Chitosan by Supported Heteropoly Acids in Heterogeneous Systems

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1078
Author(s):  
Hang Zhang ◽  
Zhipeng Ma ◽  
Yunpeng Min ◽  
Huiru Wang ◽  
Ru Zhang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Catalytic Activity ◽  
Activated Carbon ◽  
Reaction Time ◽  
High Molecular Weight ◽  
Reaction Temperature ◽  
Water Soluble ◽  
High Catalytic Activity ◽  
High Molecular Weight Chitosan

Several kinds of composite materials with phosphotungstic acid (PTA) as the catalyst were prepared with activated carbon as support, and their structures were characterized. According to the Box–Behnken central combination principle, the mathematical model of the heterogeneous system is established. Based on the single-factor experiments, the reaction temperature, the reaction time, the amount of hydrogen peroxide and the loading capacity of PTA were selected as the influencing factors to study the catalyzed oxidation of hydrogen peroxide and degradation of high molecular weight chitosan. The results of IR showed that the catalyst had a Keggin structure. The results of the mercury intrusion test showed that the pore structure of the supported PTA catalyst did not change significantly, and with the increase of PTA loading, the porosity and pore volume decreased regularly, which indicated that PTA molecules had been absorbed and filled into the pore of activated carbon. The results of Response Surface Design (RSD) showed that the optimum reaction conditions of supported PTA catalysts for oxidative degradation of high molecular weight chitosan by hydrogen peroxide were as follows: reaction temperature was 70 ℃, reaction time was 3.0 h, the ratio of hydrogen peroxide to chitosan was 2.4 and the catalyst loading was 30%. Under these conditions, the yield and molecular weight of water-soluble chitosan were 62.8% and 1290 Da, respectively. The supported PTA catalyst maintained high catalytic activity after three reuses, which indicated that the supported PTA catalyst had excellent catalytic activity and stable performance compared with the PTA catalyst.

Resveratrol encapsulation in high molecular weight chitosan-based nanogels for applications in ocular treatments: Impact on human ARPE-19 culture cells

2020 ◽  
Vol 165 ◽  
pp. 804-821 ◽  
Author(s):  
Florencia Solana Buosi ◽  
Agustina Alaimo ◽  
Mariana Carolina Di Santo ◽  
Fernanda Elías ◽  
Guadalupe García Liñares ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Culture Cells ◽  
High Molecular Weight Chitosan

scholarly journals Changes in the Respiration, Growth, and Vitamin C Content of Soybean Sprouts in Response to Chitosan of Different Molecular Weights

HortScience ◽  
2005 ◽  
Vol 40 (5) ◽  
pp. 1333-1335 ◽  
Author(s):  
Young-Sang Lee ◽  
Yong-Ho Kim ◽  
Sung-Bae Kim
Keyword(s):  
Molecular Weight ◽  
Vitamin C ◽  
High Molecular Weight ◽  
Soybean Seeds ◽  
Hypocotyl Length ◽  
Molecular Weights ◽  
Soybean Sprouts ◽  
High Molecular Weight Chitosan ◽  
Chlorophyll Formation

To study the effects of chitosan on the productivity and nutritional quality of soybean (Glycine max L.) sprouts, soybean seeds were soaked in solutions containing 1,000 ppm chitosan of low (<10 kDa), medium (50 to 100 kDa), or high (>1,000 kDa) molecular weight, and the respiration, growth, and vitamin C content of the sprouts were subsequently evaluated. Sprouts treated with high molecular weight chitosan exhibited a significant increase in respiration, 5%, within 1 day of treatment. Chitosan effectively increased the growth of the sprouts: sprouts treated with high molecular weight chitosan showed increases of 3%, 1%, 3%, 1%, and 12% in the total length, hypocotyl length, root length, hypocotyl thickness, and fresh weight, respectively, as compared to a control. The growth-improving effects of chitosan were proportional to the molecular weight of the molecule used in the treatment. Chitosan treatment did not result in any significant reduction in vitamin C content or postharvest chlorophyll formation, traits that determine the nutritional and marketing values of soybean sprouts. All these results suggest that soaking soybean seeds in a solution of chitosan, especially of high molecular weight, may effectively enhance the productivity of soybean sprouts without adverse effects on the nutritional and postharvest characteristics.

scholarly journals Activity of Chitosan and Its Derivatives against Leishmania major and Leishmania mexicana In Vitro

2019 ◽  
Vol 64 (3) ◽  
Author(s):  
Alaa Riezk ◽  
John G. Raynes ◽  
Vanessa Yardley ◽  
Sudaxshina Murdan ◽  
Simon L. Croft
Keyword(s):  
Nitric Oxide ◽  
Reactive Oxygen Species ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Leishmania Major ◽  
Oxygen Species ◽  
Leishmania Mexicana ◽  
Content Type ◽  
High Molecular Weight Chitosan

ABSTRACT There is an urgent need for safe, efficacious, affordable, and field-adapted drugs for the treatment of cutaneous leishmaniasis, which newly affects around 1.5 million people worldwide annually. Chitosan, a biodegradable cationic polysaccharide, has previously been reported to have antimicrobial, antileishmanial, and immunostimulatory activities. We investigated the in vitro activity of chitosan and several of its derivatives and showed that the pH of the culture medium plays a critical role in antileishmanial activity of chitosan against both extracellular promastigotes and intracellular amastigotes of Leishmania major and Leishmania mexicana. Chitosan and its derivatives were approximately 7 to 20 times more active at pH 6.5 than at pH 7.5, with high-molecular-weight chitosan being the most potent. High-molecular-weight chitosan stimulated the production of nitric oxide and reactive oxygen species by uninfected and Leishmania-infected macrophages in a time- and dose-dependent manner at pH 6.5. Despite the in vitro activation of bone marrow macrophages by chitosan to produce nitric oxide and reactive oxygen species, we showed that the antileishmanial activity of chitosan was not mediated by these metabolites. Finally, we showed that rhodamine-labeled chitosan is taken up by pinocytosis and accumulates in the parasitophorous vacuole of Leishmania-infected macrophages.

scholarly journals Chitosan-based biomaterials used in critical-size bone defects: radiographic study in rat's calvaria

2012 ◽  
Vol 41 (5) ◽  
pp. 312-317 ◽  
Author(s):  
Rubens Spin-Neto ◽  
Felipe Leite Coletti ◽  
Rubens Moreno de Freitas ◽  
Chaíne Pavone ◽  
Sérgio Paulo Campana-Filho ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Bone Density ◽  
High Molecular Weight ◽  
Critical Size ◽  
Bone Defects ◽  
Control Group ◽  
Low Molecular Weight ◽  
Chitosan Hydrochloride ◽  
Low Molecular Weight Chitosan ◽  
High Molecular Weight Chitosan

OBJECTIVE: This study evaluated, using digital radiographic images, the action of chitosan and chitosan hydrochloride biomaterials, with both low and high molecular weight, used in the correction of critical-size bone defects (CSBD's) in rat's calvaria. MATERIAL AND METHOD: CSBD's with 8 mm in diameter were surgically created in the calvaria of 50 Holtzman rats and these were filled with a blood clot (Control), low molecular weight chitosan, high molecular weight chitosan, low molecular weight chitosan hydrochloride and high molecular weight chitosan hydrochloride, for a total of 10 animals, which were divided into two experimental periods (15 and 60 days), for each biomaterial. The radiographic evaluation was made using two digital radiographs of the animal's skull: one taken right after the bone defect was created and the other at the moment of the sacrifice, providing the initial and the final radiographic bone density in the area of the defect, which were compared. RESULT: Analysis of radiographic bone density indicated that the increase in the radiographic bone density of the CSBD's treated with the proposed biomaterials, in either molecular weight, in both observed periods, where similar to those found in control group. CONCLUSION: Tested chitosan-based biomaterials were not able to enhance the radiographic density in the CSBD's made in rat's calvaria.

Effects of Fungal-derived High Molecular Weight Chitosan on 5-Fluorouracil-induced Adverse Reactions

2008 ◽  
Vol 23 (5) ◽  
pp. 458-472 ◽  
Author(s):  
Yih-Huei Uen ◽  
Ying-Jan Wang ◽  
Town-Ming Hsu ◽  
Mei-Huei Chen ◽  
Hing-Yuen Chan ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Adverse Reactions ◽  
High Molecular Weight Chitosan
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