Abstract: A polyion Complex (PIC) polymeric micelle is formed by interaction between a bioactive protein and a dendritic block copolymer of opposite charge. The conventional low stability of PIC micelles with bioactive proteins vis-à-vis ionic strength is offset by the stability provided by the dendritic block. The overall process for preparing the micelles is facilitated by the simplicity of the drendritic block copolymer synthesis.

Abstract: The present invention relates to a pH-sensitive PIC (polyion complex) type polymeric micelle formed by electrostatic interaction between a dendritic block copolymer and another polymer of opposite charge. The presence of a dendritic block copolymer confers high stability to the micelles in physiological conditions, while in the acid medium of tumor tissues (pH 6.5) or cell compartments, such as the endosome/lysosome (pH 5.0-5.5), the micelles tend to become destabilized, being able to selectively release drugs or macromolecules encapsulated therein. The micelles are characterized by high stability against ionic strength, dilution and temperature. They can further be lyophilized and conserved in solid state.