THEORETICAL SUBSTANTIATION OF THE PHYSICO-CHEMICAL INTERACTION OF THE ACTIVE COMPONENTS OF THE DRY EXTRACT OF GINKO BILOBA LEAVES AND CHITOSAN BY THE QUANTUM-CHEMICAL CALCULATION METHOD

Relevance. One of the main tasks arising in the design of dosage forms is the choice of the optimal combination of excipients and active ingredient. At the same time, the quantum-chemical prediction of the physicochemical properties of organic molecules of small and medium size is a promising direction. The purpose of the study is the theoretical substantiation of the physicochemical interaction of the active components of the dry extract of ginkgo biloba leaves and the gel–forming agent chitosan by a quantum chemical calculation method. Material and method. The interaction of a number of molecules included in the chitosan hydrogel was evaluated using quantum chemical calcula-tions using the semiempirical PM7 molecular orbitals method. The initial geometry was generated using the HyperChem 8 molecular modeling pro-gram. Results. The geometrical and electronic structure of molecules are presented in two approximations: taking into account hydration (the dielectric per-mittivity of the medium EPS=78.4 is given, the calculation of hydration using the A. Klamt COSMO and COSMO-RS solution models) and without taking into account hydration (in a model vacuum). Molecular descriptors used to evaluate the ability of hydrogel molecules to interact with chitosan have been calculated. Conclusions. The theoretical prediction proves the feasibility of combining rutin, quercetin and gingcolide in a mild dosage form with the use of chi-tosan as a gel-forming agent.