Modified Polysaccharides

Polysaccharide-based CSPs incorporate derivatives of cellulose and amylose adsorbed on silica gel. The selectivity of these CSPs depends upon the nature of the substituents introduced during the derivatization process. The secondary structure of the modified polysaccharide is believed to play a role in selectivity, but the chiral recognition mechanisms have not been fully elucidated [55]. 

The results of the mechanical properties can be explained on the basis of morphology. The scanning electron micrographs (SEM) of fractured samples of biocomposites at 40 phr loading are shown in figure. 3. It can be seen that all the bionanofillers are well dispersed into polymer matrix without much agglomeration. This is due to the better compatibility between the modified polysaccharides nanoparticles and the NR matrix (Fig. 4A and B). While in case of unmodified polysaccharides nanoparticles the reduction in size compensates for the hydrophilic nature (Fig. 3C and D). In case of CB composites (Fig. 3E) relatively coarse, two-phase morphology is seen. 

Polyether-modified polysaccharides mixtures of metal hydroxides polysaccharide partially etherified with hydroxyethyl and/or hydroxypropyl groups [1437]... 

J. G. Batelaan and P. M. van der Horts. Method of making amide modified carboxyl-containing polysaccharide and fatty amide-modified polysaccharide so obtainable. Patent WO 9424169,1994. 

Cationic and hydrophobe modified polysaccharides are preferred excipients for personal care products since they are substantive (adherent) to anionic or hydrophobic substrates (skin, hair, mucosa), hydrophilic, film forming, compatible with many therapeutic agents, nonpenetrating, and nonirritating. Polymer JR and Quatrisoft (Figure 1), are two such materials... 

As a result of heparin s multiplicity of biological activities and its importance as a major pharmaceutical, other polysaccharides and modified polysaccharides have been examined as potential heparin analogues in drug development (1). These heparin analogues include other GAGs, other non-GAGs, sulfated polysaccharides from plant and animal origins such as lam-... 

The chemical-enzymic approach to the synthesis of modified polysaccharides presents a good prospect for the preparation of small quantities of these polymers, which may prove very useful for immunochemical studies. The approach is certainly not limited by the specific case of Salmonella polysaccharides 10-12, and may well be extended to other polymers. The first results from this group322 show that several analogs of O-specific polysaccharides (18) of Salmonella serogroups C2 and C3 may be prepared through this approach. 

For example, it was possible to demonstrate formation of the modified polysaccharides of S. anatum in which a D-galactose residue is replaced by D-fucose, D-gluc-ose, D-talose, or 4-deoxy-D-xylo-hexose residues. 3-Deoxy-D-arabino-hexose or P-glucose residues may substitute for a P-mannose residue. 

All the KDO containing capsular polysaccharides shown in Figure 10 cross react in conventional antisera, mainly due to the fact that O-acetylation is never complete. In comparing native and modified polysaccharides we found that the immunodominant group in all these polysaccharides is KDO, acetylated or not. Closer serological study can be performed with monoclonal antibodies (Soderstrom, T, personal communication). It was found that a monoclonal K13 antibody reacts neither with the K20 nor with the K23 polysaccharides. Evidence was found that this antibody is specific for the P-(4-0-acetyl-KD0)-deter-minant of the K13 polysaccharide. 

Matsumoto T, Numata M, Anada T et al (2004) Chemically modified polysaccharide schizophyllan for antisense oligonucleotides delivery to enhance the cellular uptake efficiency. Biochem Biophys Acta 1670 91-104... 

Na K, Lee ES, Bae YH (2003) Self-assembled nanoparticles of hydrophobically-modified polysaccharide bearing vitamin H as a targeted anti-cancer drug delivery system. Eur J Pharm Biopharm 18(2) 165-173... 

Schacht, E., Ruys, L., Vermeersch, J., and Remon, J.P., Polymer-drug combinations synthesis and characterization of modified polysaccharides containing procainamide moieties, J. Controlled Release, 1, 33 46, 1984. 

Figure 3. Dependence of mass losses of wood samples on amount of applied fire-protecting coverings on the base of modified polysaccharides 1 - oxidized starch (high degree of oxidation), 2 - oxidized rice (high degree of oxidation), 3 - oxidized starch (average degree of oxidation).

Radical polymerization techniques that are for example used for the crosslinking of methacrylate-modified polysaccharides [9] are not included in this chapter. Prepolymer crosslinking through radical polymerization techniques as well as non-covalent microgel formation has recently been reviewed in a number of excellent review articles [2, 4, 10-14] and is thus not discussed within this chapter. 

Additional carbamate-modified polysaccharides, (I), were prepared by Ohnishi [1] and used in separating enantiomeric racemates of both non-aromatic heterocyclics and aromatic derivatives. 

Hydrophobically modified polymers can associate in aqueous media to form micelle-like structures above their critical association concentrations (CACs). The nanosized self-aggregates were prepared using modified natural polysaccharides such as pullulan, curdlan, and glycol chitosan. The modified polysaccharides provide excellent biocompatibility, biodegradability, low immunogenicity, and biological activities. 

Moreira JN, Almeida LM, Geraldes CF, Costa ML (1996) Evaluation of in vitro stability of large unilamellar lipsomes anchored with a modified polysaccharide (O-palmitoyl Pullulan). J Mat Sci Mat Med 7 301-303... 

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