Ionotropic gelation

Femandez-Urrusuno et al. (1999) investigated the potential of chitosan (MW <50,000-130,000 DD 70-87%) nanoparticles as a system for improving the systemic absorption of insulin following nasal instillation. Nanoparticles prepared by ionotropic gelation with tripolyphosphate... 

Tsai, M.-L., Bai, S.-W., and Chen, R.-H. (2008). Cavitation effects versus stretch effects resulted in different size and polydispersity of ionotropic gelation chitosan-sodium tripolyphosphate nanoparticle. Carbohydr. Polym. 71, 448-457. 

Another technique for the preparation of chitosan hollow fibers consists of the coagulation of the chitosan fiber in an ionotropic gelation bath followed by forced extrusion of the noncoagulated core [62, 63]. 

From detailed cell cultural studies these chitosan derivatives were shown to promote chondrogenesis. Chitosan nanoparticles are shown to enhance oral bioavailability and intestinal absorption of peptide and protein formulations. By ionotropic gelation of chitosan with tripolyphophate anions insulin-loaded nanoparticles have been prepared [230]. 

Appropriate polymeric carriers can be obtained from polymeric, oligomeric, and monomeric precursors. Due to unwanted chemical Interaction of such chemicals with the cell material larger size of these precursors Is favorable. The Ionotropic gelation, starting from polyelectrolytes and the polycondensation, starting from oligomeric epoxy resins, are typical problem solutions. 

Figure 1. Summary of polymer-counterion systems to be used in ionotropic gelation for whole cell entrapment. Reprinted, with permission, from Ref. 13. Copyright 1982, Plenum Publishing Corp.

Figure 2. Scheme for catalyst bead formation by ionotropic gelation, including... 

The radius R The radius of particles obtained from ionotropic gelation is usually controlled within very narrow limits and the size can easily be determined by microscopic measurements. 

Hot-melt extrusion process In situ polymerization Interfacial cross-linking/reaction Interfacial polymerization Ionotropic gelation... 

The vibration system is theoretically based on liquids with Newtonian flnid dynamics however, it was reported by Serp et al. that it can be applied to non-Newtonian liquids such as alginate, to make uniform drops and therefore microspheres by ionotropic gelation." The different equations can thereby be used as an approximation of the frequency and flow rates needed to break up the polymer into particles, however, it was suggested by Serp et al. and by Whelehan and Marison to determine the required values for a given nozzle diameter with an empirical approach for each system in which the calculated value is used as a starting (reference) point." It must also be noted that the size of the droplet does not necessarily equal the size of the produced bead/sphere. ... 

Modified Ionotropic Gelation under a High-Voltage Electrostatic Field.282... 

Merits of Ionotropic Gelation and Polyelectrolyte Complexation Technique...287... 

Common Laboratory Method of Encapsulation via Ionotropic Gelation.288... 

KCl by microencapsulation. In this chapter, a comprehensive attempt has beenmade to discuss the different aspects of ionotropic gelation and polyelectrolyte complexation approaches by considering these techniques as great promising tools for the development of encapsulation process. 

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