Solubilization of Some Low-Polarity Organic Compounds by Hydroxypropyl-β-cyclodextrin

Hydroxypropyl-β-cyclodextrin (HPCD), a microbially produced compound, was investigated for its potential to increase the apparent aqueous solubilities of low-polarity organic compounds. The results show that the apparent solubilities of trichloroethene, chlorobenzene, naphthalene, anthracene, and p,p′-DDT were significantly increased in HPCD solutions. The relative aqueous-phase concentrations (S_t/S_o) of the compounds increased linearly with increasing HPCD concentration. The solubilization power of HPCD is dependent on the size and relative polarity of its cavity, and, unlike micelle-forming surfactants, HPCD has no critical micelle concentration. The partition mechanism was shown to be a valid approach for interpreting the solubilization activity of HPCD. The potential application of HPCD in the remediation of contaminated groundwater is briefly discussed.