Rheological characterization of a xanthan-galactomannan hydrogel loaded with lipophilic substances.

ABSTRACT

We compared the structures and rheology of xanthan-galactomannan (XG) hydrogels with the addition of curcumin in microemulsion (XGMC) and ethanol (XGEC). XGMC hydrogels have gel characteristics and exhibited a significantly higher elastic response than the XGEC and XG hydrogels at room temperature, but after heating, an increase in the elastic modulus was observed for the last two systems. The visualization of the hydrogel microstructures by cryo-scanning electronic microscopy revealed pores within the lamellar structure only for XGMC. In vitro skin permeation tests showed a more pronounced lag time for XGMC; however, a more efficient permeation from XGMC than from XGEC. This study demonstrates that the XG system is an alternative to traditional gels for the topical applications of hydrophobic drugs.