STUDY OF INCLUSION COMPLEXES OF 2-HYDROXYPROPYL-β-CYCLODEXTRIN WITH BIOLOGICALLY ACTIVE SALINAZIDE AND VANILIN ISONIAZIDE

Complexation of 2-hydroxypropyl-β-cyclodextrin with salinazide and vanillin isoniazide possessing broncholytic and antitubercular activity was studied by the UV-spectroscopy method in a phosphate buffer solution (рН 7.4).The solubilizing effect of cyclodextrin was studied by the phase diagram method which consisted in quantitatively determining the solubility of biologically active compounds in a buffer solution containing different concentrations of cyclodextrin. The addition of cyclodextrin to a solution leads to a significant increase in the optical density of the compounds under study and in a shift in the wavelength of peak maximum indicating the formation of inclusion complexes. It was determined that the presence 2-hydroxypropyl-β-cyclodextrin in the amount of 0.09 mol kg-1 results in the 13-time solubility increase for salinazide and the 9-time solubility growth for vanillin isoniazide. Linear increase in the solubility of compounds with the addition of cyclodextrin confirms the formation of inclusion complexes compounds I, II with cyclodextrin of stoichiometric composition of 1:1. The temperature dependencies of solubility for the test compounds at different concentrations of cyclodextrin in a buffer solution were obtained. It has found that the solubility of the compounds in the presence of cyclodextrin increases with the temperature rises. Stability constants and thermodynamic parameters of complexation were calculated. Vanillin isoniazide has a lower stability constant than salinazide which is explained by the presence in its structure of methoxy group creating steric hindrance for deeper penetration of this substance into the macrocyclic cavity of the cyclodextrin. It is concluded that the process of formation of complexes is exothermic and enthalpy was determined. The results of this study showed the possibility of using 2-hydroxypropyl-β-cyclodextrin for significant increase in the solubility of the compounds, which improves their bioavailability.For citation:Ol’khovich M.V., Sharapova A.V., Blokhina S.V., Trostin A.N. Study of inclusion complexes of 2-hydroxypropyl-β-cyclodextrin with biologically active salinazide and vanilin isoniazide Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 4. P. 68-74.