Natural cationic polymers polysaccharides

Nagasaki T, Hojo M, Uno A et al (2004) Long-term expression with a cationic polymer derived from a natural polysaccharide schizophyllan. Bioconjug Chem 15 249-259... 

Chitosan is a cationic polymer, which is the second most abundant polymer in nature after cellulose and biopolymer, the most widely used in drug delivery. Chitosan is a linear copolymer polysaccharide consisting of (3 (l-4)-linked 2-amino-2-deoxy-D-glucose (D-glucosamine) and 2-acetamido-2-deoxy-D-glucose (N-acetyl-D-glucosamine) units (Figure 19.5). Chitin is the primary... 

Polysaccharide Containing Polymers. Chitosan (Table 7.3-1) is composed of 2-amino-2-deoxy p-D-glucan and is prepared from naturally occurring chitin via alkaline deacetylation. Unlike other cationic polymers chitosan is nontoxic and biodegradable, making it an ideal candidate for therapeutic applications. Although the density of positive charges of chitosan is lower than for other cationic polymers. 

PROPERTIES OF SPECIAL INTEREST Natural resources basic polysaccharides nontoxic biodegradability bioactivity biosynthesis interesting derivatives (chitosan) toughness graft copolymerization chelating ability for transition metal cations immobilizes enzymes by chemical linking or adsorption chiral polymer. 

Many PECs are prepared using chitosan as the polycationic component, therefore they will be discussed separately. Chitosan, the product of N-deacetylation of chitin, is one of the most commonly used cationic polymers of pharmaceutical interest due to its biocompatibility, nontoxicity, and mucoadhesivity. It is frequently used to form PECs, often in combination with alginate, carrageenan," hyaluronic acid, chondroitin sulfate (CS)," carboxymethyl cellulose (CMC), or poly(galacturonic acid), since these are natural anionic polysaccharides with favorable pharmaceutical properties. 

Chapter 8 is a review of the use of polysaccharides, perhaps some of the oldest and most well-known ingredients used in personal care. Because polysaccharides are derived from natural sources, the nature of the monosaccharides that comprise these sugar-based polymers and how nature designs the polysaccharides are addressed first. This discussion is followed by greater details of individual cosmetically important polysaccharides based primarily on the ionic nature of the polysaccharide, that is, anionic, cationic, nonionic, or amphoteric, which can be either naturally developed by the polysaccharide source or manipulated by human intervention and invention. The effects of hydrophobic modification of polysaccharides are also discussed. The chapter concludes with a brief discussion of certain polysaccharides that appear to have physiological effects on the human body when applied topically. 

The subject of this review is complexes of DNA with synthetic cationic polymers and their application in gene delivery [1 ]. Linear, graft, and comb polymers (flexible, i.e., non-conjugated polymers) are its focus. This review is not meant to be exhaustive but to give representative examples of the various types (chemical structure, architecture, etc.) of synthetic cationic polymers or polyampholytes that can be used to complex DNA. Other interesting synthetic architectures such dendrimers [5-7], dendritic structures/polymers [8, 9], and hyperbranched polymers [10-12] will not be addressed because there are numerous recent valuable reports about their complexes with DNA. Natural or partially synthetic polymers such as polysaccharides (chitosan [13], dextran [14,15], etc.) and peptides [16, 17] for DNA complexation or delivery will not be mentioned. 

Galactomannans, xanthan and chitosans are thickening linear polysaccharides the first one is neutral, xanthan is an anionic polysaccharide and chitosan is a cationic polymer in acidic conditions. The main physical properties of these different polysaccharides in dependence with the experimental conditions (temperature, ionic concentrations, nature of counterions...) are described. Considering alginates and gellan, a specific behaviour is observed physical gelation for which the mechanisms of gelation are discussed in relation with thermodynamic conditions. 

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