Preparation and characterization of inclusion complexes of a cationic beta-cyclodextrin polymer with butylparaben or triclosan.

The preparation of a cationic beta-cyclodextrin polymer (CPbetaCD) and its complexes with butylparaben and triclosan were reported in this paper. FT-IR and 2D 1H-1H gCOSY NMR spectra confirmed that the antibiotics could be included inside of the lipophilic cavities of CPbetaCD. The formation of complexation of CPbetaCD with the antibiotics significantly improved the water solubility. The solubility of the antibiotics linearly increased with the concentration of CPbetaCD, and the values of the association constant K1:1 of the butylparapben/CPbetaCD and triclosan/CPbetaCD complexes were 3800 and 3082 M(-1), respectively. The results also suggested that it was easier for butylparaben, which had relative smaller molecular size, to form the complexes with CPbetaCD than triclosan. Due to the targeting effect after the complexation with CPbetaCD, the antimicrobial activity of butylparaben can be significantly improved. Meanwhile, this improvement effect was not obvious for triclosan.