Nanochemistry and biotechnology
Development of polymeric micellar system for targeted delivery of antitumor drugs 
Kunitskaya L.R.1, Zheltonozhskaya T.B.1, Klepko V.V.1, Gerda V.I.2
1 Institute of Macromolecular Chemistry of the NAS of Ukraine. 48 Kharkivske shosse, Kyiv-02160, Ukraine. 
E-mail: larisa_kunitskaya@ukr.net
2 Taras Shevchenko National University of Faculty of Chemistry 60 Volodimirska St., 01033 Kyiv, Ukraine.

Recently, in search of the more effective micellar nanocontainers for poorly soluble and/or toxic drugs, we synthesized  block copolymers comprised poly(acrylic acid) and polyacrylamide: PAAc-b-PAAm (DBCs) and PAAm-b-PAAc-b-PAAm (TBCs) using RAFT/MADIX controlled radical polymerizations and studied their encapsulation capability with respect to Dox [1].
In the present work, we examined the role of external factors, in particular time, pH of solution, the presence of NaCl at СNaCl = 0.9 kg·m-3 on the behavior of micellar systems Dox/DBCs or Dox/TBCs and investigate the processes of Dox release from the DBC and TBC micelles under the influence of the drug’s concentration gradient and various surrounding medium.
For the most DBC and TBC samples, increasing the pH to 9, the addition of NaCl and the action of NaCl at pH = 9 practically did not affect the state of dispersions, that testified the high stability of their micelles under conditions close to physiological. 
The previously established tendency to significantly reduce the Dox encapsulation degree by the DBC and TBC micelles at the increase of the size of their “corona” was fully confirmed. Noticed that PAAm block’s lengthening complicated the Dox release against all environments under study. It was revealed that micelles which easily and effectively encapsulate Dox as easily "give away" the drug during dialysis.
Increasing pH of the DBC and TBC solutions to 9 prevented drug release. It can be stipulated by enhancing interaction between Dox and micellar “core” caused by the ionization of –COOH groups contained in PAAc blocks.

1.	Kunitskaya L., Zheltonozhskaya T., Destarac M., Mazieres S.,Klymchuk D. Micellar structures of PAAc/PAAm block copolymers in the processes of doxorubicin encapsulation // Mol. Cryst.& Liq.Cryst.-2018.-624:1.- P. 89-98.