Dual stimuli-responsive hydrogels for colon targeted drug delivery.

Colon targeted drug deliverysystems are promising for the treatment of local diseases. The colon possessesa diverse microbiome that secretes a number of biomolecules, such as enzymes,that can be exploited for targeted drug delivery. Here, we report the synthesisof 2-hydroxyethyl methacrylate and methacrylic acid  copolymer hydrogels crosslinked with an enzyme-sensitivecrosslinking agent. The swelling and drug release properties of hydrogels were observedin pH 1.2, pH 6.5 and pH 7.4, and in the presence of rat cecal content. Swellingstudies revealed pH responsivity of the hydrogels while the release kinetics ofmetronidazole from hydrogels containing an enzyme-labile crosslinker were fasterin the presence of rat cecal content. The results show that dual responsive hydrogelscould provide a promising platform for colonic drug delivery