pH-Responsive guar gum hydrogels for controlled delivery of dexamethasone to the intestine.

pH-Responsive hydrogel systems based on guar gum (GG), poly(acrylic acid) (PAA) and β-cyclodextrin (CD) using a non-toxic crosslinker, tetraethyl orthosilicate for intestinal delivery of dexamethasone (DX) has been reported. Hydrogels of different compositions were synthesized and evaluated for the controlled delivery of DX. The hydrogels exhibited pH-responsive swelling behavior with a maximum swelling around neutral pH. The CD-containing hydrogels deliver the drug at much slower rate in contrast to the ones without CD. Moreover, the drug release rate is found to show a strong dependence on the GG content and the effect of GG is more pronounced in case of the CD containing hydrogels. As the GG content increases, the rate of drug release decreases considerably and the drug release is prolonged. The release studies in the simulated conditions reveal that these hydrogels can be used as delivery vehicles for oral administration of DX targeting the intestine. Cell viability studies reveal the hydrogels to be biocompatible in nature thus validating them as good drug delivery systems.