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Modern pharmaceutics are actively developing towards the design of targeted drugs. The development of selectively acting formulations requires the creation of smart delivery systems based on carriers that would first find the target cells and enter them and then release the active substance locally. Nanoparticles of biocompatible and biodegradable polymers can be effectively used as such carriers. Flexible regulation of the molecular structure and architecture of polymers, as well as the modification of nanoparticles with vector molecules, allows one to construct carrier particles for the development of nanoformulations for active agents of various nature. This review presents the main approaches to the design of nanoformulations for targeted delivery, describes the methods for the preparation and study of nanoparticles based on hydrophobic and amphiphilic biodegradable lactide polymers, and discusses the effect of the molecular structure and preparation conditions on the characteristics of nanoparticles in detail. Some results of research in this area of the Kurchatov complex of NBIСS nature-like technologies are also presented.

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The kinetic of D,L‐lactide polymerization in presence of biocompatible zirconium acetylacetonate initiator was studied by differential scanning calorimetry in isothermal mode at various temperatures and initiator concentrations. The enthalpy of D,L‐lactide polymerization measured directly in DSC cell was found to be ΔH=−17.8±1.4 kJ mol−1. Kinetic curves of D,L‐lactide polymerization and propagation rate constants were determined for polymerization with zirconium acetylacetonate at concentrations of 250–1000 ppm and temperature of 160–220 °C. Using model or reversible polymerization the following kinetic and thermodynamic parameters were calculated: activation energy Ea=44.51±5.35 kJ mol−1, preexponential constant lnA=15.47±1.38, entropy of polymerization ΔS=−25.14 J mol−1 K−1. The effect of reaction conditions on the molecular weight of poly(D,L‐lactide) was shown.

Aqueous dispersions of gold and silver nanoparticles (NPs) stabilized with sodium citrate, as well as polymeric NPs based on poly(lactide-co-glycolide) (70 : 30 mol %) stabilized with poly(vinyl alcohol) have been obtained. The sizes of NPs have been determined by transmission electron microscopy (TEM), dynamic light scattering (DLS), and analytical ultracentrifugation (AUC). It has been shown that the diameter of both metallic and polymeric particles measured by TEM is significantly lower than their hydrodynamic diameter Dh determined by DLS. Moreover, it has been found that the Dh value obtained for the studied particles from DLS distributions is overestimated compared to that determined by AUC, because the AUC method is less sensitive to the particle size polydispersity and the presence of large objects in a dispersion.