Abstract
2-Hydroxypropyl-β-cyclodextrin (2HP-β-CD) is more soluble in water than α, β, or γ cyclodextrin. Although water-insoluble substances are dissolved by surfactants, the surfactants induced a number of problems. Therefore, we have studied a method for dissolving water-insoluble perfumes using 2HP-β-CD, without the need of a surfactant.First, complexes of various perfumes with 2HP-β-CD were prepared, and the solubilized amount of the perfumes was determined by high-performance liquid chromatography (HPLC). As a result, water-insoluble perfumes were dissolved in water by 2HP-β-CD, even through a surfactant was not used.The use of proton nuclear magnetic resonance (1H-NMR) confirmed that these dissolution phenomena were based on the inclusion mechanism.Next, factors which caused differences in the inclusion among perfumes were discussed. Among the perfumes with a hydroxyde (OH) group and an aromatic eater group and perfumes of low molecular weight (150-160), some perfumes were highly soluble. Obtaining the stability constant (Ke') through Higuchi's formula confirmed that the solubilization of perfumes was dependent on the concentration. It was proven that the solubilized amount of perfumes is in close relation with the addition of 2HP-β-CD, in other words, the apparent stability constant.
