Gelatin phase inversion

As a different approach, preformed hydrophilic polymers in aqueous solution can also be used for the miniemulsification process. In this case, the formulation process should be carried out in an inverse miniemulsion with a hydrophobic continuous phase. In order to obtain microgel nanoparticles, the polymer chains have to be crosslinked in the inverse miniemulsion prior to the transfer to an aqueous continuous phase. As a nice example, gelatin has been used for the formation of microgel nanoparticles [4],... 

Heidel [39] prepared polysaccharide-acrylate graft polymeric absorbents using an inverse emulsion process. A combination of a lipophilic and a hydrophilic nonionic surfactant was used as dispersant. The combination of surfactants allowed both the aqueous monomer and the starch to be finely dispersed in the continuous oil phase, without gelatinization of the starch. Higher monomer concentrations in the aqueous phase were also possible, which helped the efficiency of the grafting reaction. Persulfates were used as the initiators. 

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