Ionic gelation polymer systems

For instance, Yadav and Ahuja prepared nanoparticles using gum cordia as the polymer and to evaluate them for ophthalmic delivery of fluconazole. A w/o/w emulsion containing fluconazole and gum cordia in aqueous phase, methylene chloride as the oily phase, and dioctyl sodium sulfosuccinate and polyvinyl alcohol as the primary and secondary emulsifiers, respectively, were cross-linked by the ionic gelation technique to produce a fluconazole-loaded nanoreservoir system. The formulation of nanoparticles was optimized using response surface methodology. Multiple response simultaneous optimizations using the desirability approach were used to find optimal experimental conditions. The optimal conditions were found to be concentrations of gum cordia (0.85%, w/v), di-octyl sodium sulfosuccinate (9.07%, w/v), and fluconazole (6.06%, w/v). On comparison of the optimized nanosuspension formulation with commercial formulation, it was found to provide comparable in vitro corneal permeability of... 

Rochas and Rinaudo [569] constructed a phase diagram, where the logarithm of the total ionic concentration is plotted vs the reciprocal transition temperature (see Fig. 221). It characterizes the conformation and gelation of kappa carrageenan in KCl solutions. In domain I (relatively low concentration and high temperatureX only polymer coils are present in domain II (relatively low concentration and low temperature), the kappa carrageenan molecules are in the ordered, helical conformation, whereas in domain in (relatively high concentration and low temperature the system is in the (helical) gel state the boundary between domains II and III is not sharply known and for that reason is indicated by a wavy line. 

---