Chitosans tripolyphosphate complexes

Mi FL, Shyu SS, Lee ST et al (1999) Kinetic study of chitosan-tripolyphosphate complex reaction and acid-resistive properties of the chitosan-tripolyphosphate gel beads prepared by in-liquid curing method. J Polym Sci Pol Phys 37 1551—1564... 

A simple example of gel formation is provided by chitosan tripolyphosphate and chitosan polyphosphate gel beads the pH-responsive swelling abihty, drug-release characteristics, and morphology of the gel bead depend on polyelectrolyte complexation mechanism and the molecular weight. The chitosan beads gelled in pentasodium tripolyphosphate or polyphosphoric acid solution by ionotropic cross-hnking or interpolymer complexation, respectively. 

Mi FL, Shyu SS, Wong TB et al (1999) Chitosan-polyelectrolyte complexation for the preparation of gel beads and controlled release of anticancer drug. II. Effect of pH-dependent ionic crosslinking or interpolymer complex using tripolyphosphate or polyphosphate as reagent. J Appl Polym Sci 74 1093-1107... 

Another approach to reach delayed release from chitosan matrices are ionic interactions with polyanions. The formation of a polyelectrolyte complex membrane prevents early drug release. Via this method microcapsules can be formed between chitosan and alignate or even nanoparticles can be derived upon the complexation of chitosan with the polyanion tripolyphosphate. 

Shu, X. Z. and Zhu, K. J. A novel approach to prepare tripolyphosphate/chitosan complex beads for controlled release drug delivery. Int. J. Pharm. 201 (2000), 51-58. 

Agglomeration of chitosan microspheres was used as a technique for fabrication of bone scaffolds by a complex process of chitosan spheres extrusion, scaffold formation by compression followed by the spheres agglomeration and bonding with crosslinking agent (STPP, sodium tripolyphosphate) [117]. 

Chitosan as the cationic polysaccharide has been used with the anionic polysaccharides, carrageenan, and alginate for ionic complexation. Chitosan-carrageenan nanoparticles cross-linked with tripolyphosphate were prepared by corporation of polyelectrolyte complexation and ionic gelation (Grenha et al., 2010). 

---