Nanochemistry and biotechnology 

Double hydrophilic block copolymers for drug delivery
Kunitskaya L.R.1, Zheltonozhskaya T.B1., M. Destarac2, S. Mazieres2
1Taras Shevchenko National University of Kyiv, Faculty of Chemistry, Department of Macromolecular Chemistry, 60 Volodimirska St., 01033 Kyiv, Ukraine 
e-mail: larisa_kunitskaya@ukr.net
2 IMRCP,UMR CNRS 5623 Université deToulouse,118 route de Narbonne, 
31062 Toulouse Cedex 9, France

Polymeric micellar nanocontainers are considered as one of the most promising delivery systems of many hydrophobic drugs into certain cells of living organisms. 
It was shown earlier that asymmetric diblock and triblock copolymers comprised chemically complementary (methoxy)poly(ethylene oxide)/polyacrylamide (DBCMOPEO/PAAm and TBCPEO/PAAm) and partially hydrolyzed triblock copolymer derivative (TBCPEO/P(AAm-co-AAc) form special micellar structures in aqueous solutions. The ability of these micelles to encapsulate a toxic anticancer drug doxorubicin (Dox) and to enhance its cytotoxicity as compared to pure Dox has been discovered. 
Later, two series of analogous asymmetric block copolymers containing blocks of poly(acrylic acid) with constant chain length and polyacrilamide blocks with variable chain length (DBCPAAc/PAAm and TBCPAAc/PAAm) were also synthesized using RAFT/MADIX technique and their special micellar properties in aqueous medium has been proved.
 In the present work, we studied the encapsulation capability of DBCPAAc/PAAm and TBCPAAc/PAAm micelles with respect to Dox by the methods of static light scattering, FTIR, UV-Vis, TEM and examined a biological action of the drug/micelles compositions on cancer cells. The effect of significant reduction in the encapsulation capability of the DBC and TBC micelles with respect to Dox at the increase in PAAm block length was established. It was also found a decrease in the Dox encapsulation degree by the DBC and TBC micelles at the pH lowering that was stipulated by a strong stabilization of micellar structures.
DBCPAAc/PAAm micelles were shown to encapsulate Dox more effectively as compared to TBCPAAc/PAAm ones. The results of biological tests carried out against human T-leukemia cells indicated a high cytotoxicity of both created micellar systems with the drug. Thus, a real prospect for their possible application in the cancer therapy is opened.