Complex formation of chlorhexidine gluconate with hydroxypropyl-â- cyclodextrin (HPâCD) by proton nuclear magnetic resonance spectroscopy (1H NMR)

RENEE ONNAINTY, MARCELA LONGHI, GLADYS GRANERO

ELSEVIER SCI LTD

Año: 2011 vol. 346 p. 1037 - 1037

he complex formation of chlorhexidine digluconate (CHX-G2) with hydroxypropyl-b-cyclodextrin(HPbCD) was studied using NMR spectroscopy. The results revealed that this surfactant agent showsan monomer/aggregate equilibrium, which is dependent on the concentration of this drug. This equilibriumcan be modified by the presence of HPbCD, which reduces the aggregation of the CHX-G2 molecules.An inclusion process of the CHX-G2 aromatic residue within the cyclodextrin cavity was confirmed by 2DROESY spectroscopy. 1H NMR titration studies of CHX-G2 with HPbCD in D2O confirmed the formation ofhigher order complexes between CHX-G2 and HPbCD. Moreover, the addition of HPbCD into CHX-G2 solutionsforms insoluble aggregates. Such insoluble aggregates may result in the stacking of CHX-G2 moleculeson the surface of the CHX-G2:HPbCD complexes