Amphiphilic copolymers with terminal alkylthio groups capable of self-assembly at room temperature and nanoparticle formation with increasing temperature have been synthesized. Using the method of dynamic light scattering, it was found that when the critical temperature is exceeded, the size of the aggregates increases and the entrapment of a number of hydrophobic substances, including antitumor drugs, is possible. The patterns of changes in particle size depending on the architecture of amphiphilic copolymers of N-vinyl-2-pyrrolidone have been established, and the key role of molecular weight, copolymer composition, and the structure of the alkylthio group has been shown. By varying these parameters, it is possible to obtain both N-vinyl-2-pyrrolidone copolymers that form micelles at room temperature and those that form micelles at elevated temperatures. The developed approach allows to obtain nano-sized forms of paclitaxel and also allows the co-immobilization of drugs, which may be of interest for combined chemotherapeutic effects. The thermal reversibility of the nanoparticle formation was demonstrated, which allows us to classify the studied N-vinyl-2-pyrrolidone copolymers as smart polymers. Some examples of release kinetics of model substances, including antioxidants and cytostatics, are described. Patterns of changes in the critical concentrations of micelle formation with variation of the structure and molecular weight of N-vinyl-2-pyrrolidone copolymers, which do not exhibit thermotropic effect and are capable of self-assembly even at room temperature, have been determined.

Conflicts of interest:
The authors declare that they have no conflict of interest in the publication of this article. The authors have no conflicts of interest to report in this work. Abstract was not submitted elsewhere and was first published here.

Funding:
This work was supported by the Ministry of Science and Higher Education of the Russian Federation (Contract No. 075-00277-24-00).