Chemospecific manipulations of a rigid polysaccharide: syntheses of novel chitosan derivatives with excellent solubility in common organic solvents by regioselective chemical modifications

1991 ◽  
Vol 24 (17) ◽  
pp. 4745-4748 ◽  
Author(s):  
Shinichiro Nishimura ◽  
Osamu Kohgo ◽  
Keisuke Kurita ◽  
Hiroyoshi Kuzuhara
Keyword(s):  
Organic Solvents ◽  
Chemical Modifications ◽  
Chitosan Derivatives

Syntheses of Novel Chitosan Derivatives Soluble in Organic Solvents by Regioselective Chemical Modifications

1990 ◽  
Vol 19 (2) ◽  
pp. 243-246 ◽  
Author(s):  
Shin-Ichiro Nishimura ◽  
Osamu Kohgo ◽  
Keisuke Kurita ◽  
Chidchom Vittavatvong ◽  
Hiroyoshi Kuzuhara
Keyword(s):  
Organic Solvents ◽  
Chemical Modifications ◽  
Chitosan Derivatives

scholarly journals Chitosan Derivatives and Their Application in Biomedicine

2020 ◽  
Vol 21 (2) ◽  
pp. 487 ◽  
Author(s):  
Wenqian Wang ◽  
Qiuyu Meng ◽  
Qi Li ◽  
Jinbao Liu ◽  
Mo Zhou ◽  
...  
Keyword(s):  
Chemical Modification ◽  
Functional Groups ◽  
Organic Solvents ◽  
Chemical Reactions ◽  
Delivery System ◽  
Water Solubility ◽  
Delivery Systems ◽  
Ph Sensitivity ◽  
Chitosan Derivatives ◽  
Application Scope

Chitosan is a product of the deacetylation of chitin, which is widely found in nature. Chitosan is insoluble in water and most organic solvents, which seriously limits both its application scope and applicable fields. However, chitosan contains active functional groups that are liable to chemical reactions; thus, chitosan derivatives can be obtained through the chemical modification of chitosan. The modification of chitosan has been an important aspect of chitosan research, showing a better solubility, pH-sensitive targeting, an increased number of delivery systems, etc. This review summarizes the modification of chitosan by acylation, carboxylation, alkylation, and quaternization in order to improve the water solubility, pH sensitivity, and the targeting of chitosan derivatives. The applications of chitosan derivatives in the antibacterial, sustained slowly release, targeting, and delivery system fields are also described. Chitosan derivatives will have a large impact and show potential in biomedicine for the development of drugs in future.

Chitosan and Its Derivatives - Biomaterials with Diverse Biological Activity for Manifold Applications

2019 ◽  
Vol 19 (9) ◽  
pp. 737-750 ◽  
Author(s):  
Paulina Paul ◽  
Beata Kolesinska ◽  
Witold Sujka
Keyword(s):  
Biological Activity ◽  
Biomedical Applications ◽  
Chemical Properties ◽  
Alkaline Solutions ◽  
Chemical Modifications ◽  
Solubility In Water ◽  
Chitosan Derivatives ◽  
Main Obstacle ◽  
Derivatives Of ◽  
Diverse Biological Activity

Derived from chitin, chitosan is a natural polycationic linear polysaccharide being the second most abundant polymer next to cellulose. The main obstacle in the wide use of chitosan is its almost complete lack of solubility in water and alkaline solutions. To break this obstacle, the structure of chitosan is subjected to modification, improving its physic-chemical properties and facilitating application as components of composites or hydrogels. Derivatives of chitosan are biomaterials useful for different purposes because of their lack of toxicity, low allergenicity, biocompatibility and biodegradability. This review presents the methods of chemical modifications of chitosan which allow to obtain tailor- made properties required for a variety of biomedical applications. Selected pharmaceutical and biomedical applications of chitosan derivatives are also highlighted. Possibility to manage waste from arthropod and crab processing is also emphasized.

New Trends in Bioactive Chitosan Derivatives: Use of “Standardized Intermediates” with Excellent Solubility in Common Organic Solvents

1992 ◽  
pp. 533-542 ◽  
Author(s):  
Shin-Ichiro Nishimura ◽  
Osamu Kohgo ◽  
Shigeru Ishii ◽  
Keisuke Kurita ◽  
Keiko Mochida ◽  
...  
Keyword(s):  
Organic Solvents ◽  
Chitosan Derivatives

UNTERSUCHUNGEN ÜBER DIE EXTRAKTION DES ROTEN KOBER-FARBSTOFFS DURCH ORGANISCHE LÖSUNGSMITTEL ZUR ÖSTROGENBESTIMMUNG IM HARN

1960 ◽  
Vol XXXV (I) ◽  
pp. 34-48 ◽  
Author(s):  
Gerd Ittrich
Keyword(s):  
Menstrual Cycle ◽  
Organic Solvents ◽  
Urine Sample ◽  
Phenol Derivatives ◽  
Organische Lösungsmittel ◽  
Colour Complex

ABSTRACT A series of organic solvents and phenol derivatives have been examined for the extraction of the pink Kober-colour complex. Optimal results could be achieved for fluorimetry by a solution of 2 % (w/v) p-nitrophenol and 1 % (v/v) ethanol in acetylenetetrabromide, when the green mercury line (546 mμ was used as primary light. The sensitivity, stability and specificity have been improved, compared with the previously described reaction. By changing the sequence of purification steps and by reducing the volume of the urine sample (5 ml) the method for the determination of total oestrogens has been simplified. Approximately 10 determinations can be done within 3–4 hours by one person. Recovery experiments and comparative determinations with a previously described method have been carried out. The excretion of total oestrogens in a complete menstrual cycle is determined with the described method.

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