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Chitins

A special issue of Materials (ISSN 1996-1944).

Deadline for manuscript submissions: closed (28 October 2010) | Viewed by 17767

Special Issue Editor

Special Issue Information

Dear Colleagues,

The research history on chitin was started around 1970-1980, which was the 1st stage on chitin research. Now is going on the 2nd stage both fundamental and industrial fields.
To overview the recent publications, in my opinion, study on chitin (include chitosan) seems to be saturated or stopped. With opening the special issue “chitin”, I strongly hope the very exciting, break-through, scientific, and industrial valuable works.

Dr. Hitoshi Sashiwa
Guest Editor

Keywords

  • chitin
  • chitosan
  • exciting
  • break-through
  • 2nd stage

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558 KiB  
Article
Different Molecular Weight Chitosan-Based Membranes for Tissue Regeneration
by Rubens M. Freitas, Rubens Spin-Neto, Luiz Carlos Spolidório, Sergio Paulo Campana-Filho, Rosemary Adriana C. Marcantonio and Elcio Marcantonio, Jr.
Materials 2011, 4(2), 380-389; https://doi.org/10.3390/ma4020380 - 10 Feb 2011
Cited by 9 | Viewed by 8417
Abstract
Natural polymers, such as chitosan, obtained from chitin, are been widely studied for use in the tissue regeneration field. This study established a protocol to attain membranes made from this biopolymer, consisting of high or low molecular weight chitosan. The biocompatibility of these [...] Read more.
Natural polymers, such as chitosan, obtained from chitin, are been widely studied for use in the tissue regeneration field. This study established a protocol to attain membranes made from this biopolymer, consisting of high or low molecular weight chitosan. The biocompatibility of these membranes was histologically evaluated, comparing them to collagen membrane surgically implanted in rat subcutaneous tissue. Fifteen Holtzmann rats were divided in three experimental groups: High and Low Molecular Weight Chitosan membranes (HMWC and LMWC) and Collagen membranes (C—control group); each of them with three experimental periods: 7, 15 and 30 days. As a result, after the seven days evaluation, the membranes were present and associated with a variable degree of inflammation, and after the 15 and 30 days evaluations, the membranes were absent in all groups. It is concluded that the chitosan-based membranes were successfully attained and presented comparable resorption times to collagen membranes. Full article
(This article belongs to the Special Issue Chitins)
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1871 KiB  
Article
In vitro Evaluation of Acyclovir/Chitosan Floating Systems
by Roberto Ruiz-Caro and María D. Veiga
Materials 2010, 3(12), 5195-5211; https://doi.org/10.3390/ma3125195 - 6 Dec 2010
Cited by 8 | Viewed by 8684
Abstract
Chitosan (CS) floating lyophilized formulations (L) for gastric drug delivery of acyclovir (ACV) have been developed. The freeze-dried formulations were obtained from acidic aqueous suspensions prepared with different ACV/CS ratios. No changes in ACV crystallinity were observed during X-ray diffraction powder studies as [...] Read more.
Chitosan (CS) floating lyophilized formulations (L) for gastric drug delivery of acyclovir (ACV) have been developed. The freeze-dried formulations were obtained from acidic aqueous suspensions prepared with different ACV/CS ratios. No changes in ACV crystallinity were observed during X-ray diffraction powder studies as a consequence of the manufacturing process. Considering that fed and fasted states modified the intragastric pH, swelling and in vitro dissolution studies were carried out in different acidic media (0.1 M HCl and progressive pH medium) in order to understand the influence of these physiological states on ACV/CS formulations. Swelling behavior of the floating lyophilized formulations was dependent on CS and ACV proportions within L and on medium nature due to pH dependent CS solubility. Furthermore, no interactions between ACV and CS were detected in solid state according to the X-ray studies. In vitro dissolution of ACV from L was influenced by the swelling behavior. However, it is feasible to optimize the ACV/CS ratios to achieve a desired formulation that releases the total quantity of ACV at a specific time. Moreover, floatability was assessed by buoyancy tests. The results demonstrated that the freeze-drying process achieved effective floating systems capable of remaining within the stomach while the total amount of ACV is released from L. Full article
(This article belongs to the Special Issue Chitins)
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