Use of complexation hydrogels for oral delivery of chemotherapeutic agents

Carriers were synthesized to target delivery of a chemotherapeutic agent, bleomycin, to the upper small intestine. Release of bleomycin was initiated in response to hydrogen bonding complexation/decomplexation associated with the pH shift when entering the upper small intestine from the stomach. Hydrogel nanospheres composed of methacrylic acid (MAA) and poly(ethylene glycol) (PEG) [P(MAA-g-EG)] were loaded with bleomycin. Loading of bleomycin was performed by in situ polymerization and release of bleomycin from the nanospheres was measured by UV spectrophotometry. Results showed that bleomycin release from the nanospheres was responsive to the pH of the environment surrounding the nanospheres. In addition to pH-responsive release of bleomycin, the hydrogel nanospheres were also able to enhance drug permeability through an in vitro model of the intestinal epithelium. Increasing the permeability of the intestinal epithelium could aid the transport of bleomycin from the lumen of the small intestine out into the bloodstream.