Polysaccharides drug-linked

Molteni, L. 1982. Effects of the polysaccharidic carrier on the kineticfate of drugs linked to dextran and inulin in macromolecular compounds. Optimization of Drug Delivery, edited by H. Bundgaard.A. B. Hansen, and H. Kofod, 285-300. Copenhagen Munksgaard. 

Nishi et al. [110] used dextran and dextrin as chiral selectors in capillary-zone electrophoresis. Polysaccharides such as dextrins, which are mixtures of linear a-(l,4)-linked D-glucose polymers, and dextrans, which are polymers of D-glucose units linked predominantly by a-(l,6) bonds, have been employed as chiral selectors in the capillary electrophoretic separation of enantiomers. Because these polymers are electrically neutral, the method is applicable to ionic compounds. The enantiomers of basic or cationic drugs such as primaquine were successfully separated under acidic conditions. The effects of molecular mass and polysaccharide concentration on enantioselectivity were investigated. 

A special group of carrier-linked prodrugs are the site-specific chemical delivery systems [23], Macromolecular prodrugs are synthetic conjugates of drugs covalently bound (either directly or via a spacer) to proteins, polypeptides, polysaccharides, and other biodegradable polymers [24],... 

Further examples of enzymatically degradable drug formulation wrappings are capsule shells made of the polysaccharides chitosan [65,66] or cross-linked dextran [67]. 

This data demonstrate that amino-type drugs can be easily linked in high yield onto succinoylated polysaccharides. However this only holds for polysaccharide derivatives having all hydroxyls esterified. When a similar reaction sequence as described before was carried out using a partially succinoylated inulin (approx. 50% esterified) a considerable amount of crosslinked product was obtained. The remaining free hydroxyl functions apparently compete with the amino compounds for reaction with the imidazolide derivative. Hence the above described method is only attractive provided the polysaccharide is succinoylated quantitatively. 

The procedure for the preparation of cross-linked chitosan microspheres coated with polysaccharide or lipid for intelligent drug delivery systems is illustrated in Fig. 11 [230]. 

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