Synthesis of carboxymethyl Xanthan/ double-walled carbon nanotube hybrid hydrogel nanocomposite for transdermal release of drug

ABSTRACT The inclusion of double-walled carbon nanotubes in carboxymethyl xanthan-based hydrogels was developed in order to improve both mechanical and drug release (diclofenac) properties of these nanocomposites for potential application in the biomedical field. The synthesis of carboxymethyl xanthan was carried out by an esterification reaction between xanthan gum and monochloroacetic acid, and the grafting was confirmed by FTIR analysis. The obtained carboxymethyl derivatives exhibited higher hydrophilicity degrees of substitution compared to the native xanthan gum. The nanocomposites prepared using either raw or modified xanthan gum were characterized in terms of physical properties, and we evidenced both an increase in viscoelasticity by one order of magnitude and an improved distribution of the nanotubes within the hydrogel matrix in the case of the carboxymethyl xanthan. The trapping efficiency of diclofenac was improved by the addition of the nanotubes, reaching up to 74 wt %. While the nanotubes also allowed a slower release of the molecule. An in-vitro study was carried out to ensure that the CNTs grafted onto the modified CMX were not released during the diffusion of the active ingredient.