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BACKGROUND : Chitosan, derived from chitin, has a poor solubility which limits its application greatly. For improving its dissolubility, according to the feature that intramolecular hydroxy and amino group in chitosan are easy to be chemically modified, and functional groups are introduced to improve its solubility and functionality to widen the range of its application, which has become one of the new trend of development for investigating the application of chitosan. OBJECTIVE: To sum up the research advancements in the application and modification of chitosan in carboxylation,acylation, alkylation, etherification, etc.RETRTEVE STRATEGY: The relevant articles published in English between 1998 and 2007 were searched for in Pubmed database with the key words of "chitosan, modification", and the relevant articles published between 1998 and 2007 were searched for in Elsevier Science database with the key words "chitosan, modification" and search "derivate" within search results in English. Articles closely related to the structural modification and application of chitosan were involved, and repetitive and old studies were excluded.LTTERATURE EVALUATION: Totally 154 articles were selected, and 30 of them are accorded with the inclusive criteria,including 5 are reviews, and the others are clinical or experimental studies.DATA SYNTHESTS: The intramolecular hydroxy and amino groups in chitosan are mostly modified because they are easy to be chemically modified. Recently, reports lay particular emphasis on the modification in carboxylation, acylation,alkylation, etherification, etc. Functional groups are introduced to improve its solubility and functionality to widen the range of its application.CONCLUSTON: The water-solubility of chitosan can be improved through structural modification and introducing multifunctional group, which can also bring about much more special efficacies.
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This article introduces the progress about study of lipid mdeiating action of chitosan. It was found that chitosan could mediate blood lipids and modification of chitosan could improve its lipid mediating activity in animal and human.
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Objective To study the absorption and distribution of low molecular N-trimethyl chitosan chloride in mice.Methods Using tritium marking method to determine the concentrations of low molecular N-trimethyl chitosan chloride in serum after oral administration.Its pharmacokinetics were analysed by DAS ver1.0 program and the distributions in tissues were examined. Results The pharmacokinetics of low molecular N-trimethyl chitosan chloride were consistent with two-compartment model.The radioactive concentrations in liver,kidney,lung and spleen were higher than those in other tissues.And the radioactive concentration in cancer was higher. Conclusion Low molecular N-trimethyl chitosan chloride could be absorbed after oral administration.It was easily conjugate with cancer surface and could be developed as an anticancer drug for oral use in the future.