Preparation and characterization of stable water soluble hybrid nanostructures of hydrophobic compounds by encapsulation into nanoparticles of amphiphilic N-vinylpyrrolidone copolymers of new generation

Abstract

Abstract The conditions for obtaining stable aqueous solutions of prospective pharmaceutical: a lipophilic aminonitroxyl platinum complex, namely, e-amine-d-(4-amino-2, 2, 6, 6-tetramethylpiperidine 1-oxyl)-a, fbis(octanoato)-b, c-dichloroplatinum(IV) (PNC), and a dye zinc tetraphenylporphyrinate (ZnTPP) by means of their solubilization with polymer particles of N-vinylpyrrolidone with dimethacrylate. Aqueous solutions of PNC and ZnTPP encapsulated into polymer particles were investigated by dynamic light scattering, and the temperature dependence of nanostructure sizes was studied. According to transmission electron microscopy, the hybrid nanostructures are core—shell particles, in which the PtIV complex forms small clusters (∼4 nm). It was established by ESR and voltammetric measurements that the free radical fragment of the aminonitroxyl PtIV complex kept its mobility and the same ESR and redox characteristics as the 4-acetylamino-2, 2, 6, 6-tetramethylpiperidine 1-oxyl radical. The obtained results indicate that biocompatible copolymers of N-vinylpyrrolidone are of interests as carriers and delivery tools for ZnTPP and organic PtIV complexes. Hybrid structures of given dimensions and properties can be created on their basis necessary for biomedical applications.