Biological chitosan

Micro emulsions based on a heparin-chitosan complex suitable for oral administration based on ingredients acceptable to humans were studied with or without biologically active ingredients. Appropriate mixing and modifications of these microemulsions lead to nanometer-sized heparin-chitosan complexes [108]. 

Chitosan acetate and lactate salt films have been tested as wound-healing materials. Mechanical, bioadhesive and biological evaluation of the films were carried out. The results were compared to Omiderm . Chitosan lactate exhibited a lower tensile strength, however, it was more flexible and bioadhesive than chitosan acetate. Chitosan lactate and Omiderm did not cause any allergic reactions in contrast, chitosan acetate produced skin irritation clearly due to the anion. Nevertheless, no sign of toxicity was encountered when the extracts of three preparations were administered parenterally [244]. 

The biological significance of chitosan biomaterials in the hiunan body depends largely on the actions that certain hydrolases exert on them. The resulting chitoohgomers stimulate various cells, while the released monomers are phosphorylated and incorporated into hyaluronan, keratan sulphate and chondroitin sulphate, components of the intracellular matrix and connective tissue [348]. 

Chen R.H., Tsaih M.L. 1998. Effect of temperature on the intrinsic viscosity and conformation of chitosans in dilute HCl solution. International Journal of Biological Macromolecules 23,135-141. 

Similar structures were later employed to create original dendronized polymers 485 and 486, based on a chitosan backbone and using such sialodendrons as 484 (Fig. 50).328 Chitosan itself is nontoxic, biodegradable, and has widespread biological activities, but major intrinsic drawbacks such as low solubility in both organic solvents and water have hampered its development as a bioactive polymer. Thus, the synthesis of water-soluble... 

Kang HS, Park SH, Lee YG et al (2007) Polyelectrolyte complex hydrogel composed of chitosan and poly(y-glutamic acid) for biological application Preparation, physical properties, and cytocompatibility. J Appl Polym Sci 103 386-394... 

Methods were described for the incorporation of proteins in the form of noncovalent complexes with polycationic reagents, into sustained release systems where the polycation stabilizes the protein against inactivation while it resides in the delivery device, and retards release of the protein from the delivery device [469,470]. A variety of polycations have been used, including simple polyamino acids such as polylysine or polyarginine, protamine and chitosan. The end result was the release of the active agent with retention of biological activity, with a high cumulative field and over a sustained period of time. 

Kim, S. K. (2010). Chitin, Chitosan, Oligosaccharides and Their Derivatives Biological Activities and Applications. CRC Taylor Francis, USA (pp. 666). 

Kim, S. K. and Rajapakse, N. (2005). Enzymatic production and biological activities of chitosan oligosaccharides (COS) A review. Carbohydr. Polym. 62, 357-368. 

Chitosan, the most abundant marine mucopolysaccharide, is derived from chitin by alkaline deacetylation, and possesses versatile biological properties such as biocompatibility, biodegradability, and a non-toxic nature. Due to these characteristics, considerable attention has been given to its industrial applications in the food, pharmaceutical, agricultural, and environmental industries. Currently, chitosan can be considered as a potential marine nutraceutical because its remarkable biological activities have been investigated and reported, in order to exploit its nutraceutical... 

Because the biological properties of chitosan are dependent on its physico-chemical properties such as molecular weight (MW) and degree of deacetylation (DD), uniform physico-chemical properties are a prerequisite to specific industrial applications. As an alternative method, fermentation technology for chitosan preparation from fungal cell walls has received much attention as an eco-friendly pathway. Rane and... 

Because it has a variety of biological activities such as antioxidant, antimicrobial, anti-inflammatory, anticancer, and immune-stimulating effects, chitosan offers a number of uses in food, cosmetic, biomedical, and pharmaceutical industries. In this section, the nutraceutical properties of chitosan and its derivatives are discussed. 

Singla AK, Chawla M. Chitosan some pharmaceutical and biological aspects—an update. J Pharm Pharmacol 2001 53(8) 1047. 

Chitosan has been the focus of reasearch as a pharmaceutical excipient due to its specific chemically and biologically favorable features [6-8]. As chitosan is soluble in acidic aqueous solutions, it can be processed under acidic conditions. By contrast, as the product made by chitosan is insoluble at neutral or basic pH, it behaves as a delivery system under such conditions. These chemical properties allow chitosan to control drug delivery. Further,... 

Specific Physicochemical and Biological Characteristics of Chitosan Useful for Improvement of Drug Action or Enhancement of Drug Absorption... 

Carreno-Gomez, B., and R. Duncan. 1997. Evaluation of the biological properties of soluble chitosan and chitosan microspheres. Int J Pharm 148 231. 

Abstract Carbohydrates have been investigated and developed as delivery vehicles for shuttling nucleic acids into cells. In this review, we present the state of the art in carbohydrate-based polymeric vehicles for nucleic acid delivery, with the focus on the recent successes in preclinical models, both in vitro and in vivo. Polymeric scaffolds based on the natural polysaccharides chitosan, hyaluronan, pullulan, dextran, and schizophyllan each have unique properties and potential for modification, and these results are discussed with the focus on facile synthetic routes and favorable performance in biological systems. Many of these carbohydrates have been used to develop alternative types of biomaterials for nucleic acid delivery to typical polyplexes, and these novel materials are discussed. Also presented are polymeric vehicles that incorporate copolymerized carbohydrates into polymer backbones based on polyethylenimine and polylysine and their effect on transfection and biocompatibility. Unique scaffolds, such as clusters and polymers based on cyclodextrin (CD), are also discussed, with the focus on recent successes in vivo and in the clinic. These results are presented with the emphasis on the role of carbohydrate and charge on transfection. Use of carbohydrates as molecular recognition ligands for cell-type specific dehvery is also briefly... 

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