INCLUSION COMPLEXES OF PESTICIDES IN HYDROXYPROPYL- β-CYCLODEXTRINE. EFFECTS ON THEIR WATER SOLUBILITY

Abstract

A set of “host” compounds, highly suluble in water, were prepared by the reaction of β-cyclodextrin with propylene oxide in NaOH solution. The reactant ratio was varied in order to examine the difference in the substitution degree of the obtained derivatives. The structure was determined by the 1H-NMR spectra. The average degree of substitution was determined by integration of the corresponding NMR signals of the methyl group, which is part of the hydroxypropyl group and the signal from the proton attached to anomeric carbon of the β-cyclodextrin. The solubility of four different pesticides, very poorly soluble in water, was measured in water and in aqueous solution of the hydroxypropyl substituted cycloheptaamylose by ultraviolet spectrophotometry. Obtained results showed that the aqueous solution of hydroxypropyl-β- cyclodextrin was powerful solubilizer of investigated pesticides due to formation of stable inclusion complexes.