Physicochemical properties of zinc oxide nanoparticles modified with betulin diphosphate

Relevance. Zinc oxide nanoparticles (ZnO NPs) are a promising component of drugs in the treatment of various dermatological diseases, due to the fact that they exhibit high antioxidant, prooxidant, and immunomodulatory properties. ZnO NPs are able to act on the bacterial cell membrane, causing apoptosis, and they are also capable of acting as a delivery vector for active pharmaceutical ingredients, because they are highly permeable through the skin. Immobilization of lupan triterpenoids on the surface of zinc oxide nanoparticles makes it possible to solve the main problem in creating wound dressings with ZnO NPs based on polymeric materials, such as the instability of nanoparticles, their aggregation, and the possibility of a "protein corona" forming when penetrating through the skin. As a triterpenoid of the lupane series, betulin diphosphate (BDP) was chosen, which exhibits wound healing, antioxidant, antitumor and anti-burn properties. BDP is a potential active pharmaceutical ingredient for the treatment of skin diseases. The aim of the work was to develop a method for the synthesis of stable ZnO NPs with immobilized betulin diphosphate, study their physicochemical properties, standardize and validate the procedure for the quantitative determination of ZnO NPs modified with betulin diphosphate (ZnO NPs-BDP). Material and methods. The physicochemical properties of the obtained ZnO NPs-BDP were studied by methods such as IR, UV, and photoluminescent spectroscopy, determination of the hydrodynamic diameter, zeta potential, and specific surface area. The identification of the studied nanoparticles was carried out using these methods. Results. Using powder X-ray diffraction and scanning electron microscopy, it was shown that the immobilization of BDP on the surface of ZnO NPs did not change the structure and practically did not affect the size of the nanoparticles. Conclusion. Thus, we experimentally substantiated the method of obtaining ZnO NPs with immobilized BDP by two methods (boiling zinc oxide nanoparticles in an alcoholic solution of BDP or in a solution of BDP disodium salt hydrate in the presence of a phosphate buffer). The method for the quantitative determination of zinc oxide in the ZnO NPs-BDP substance satisfies the criteria for accuracy and repeatability.