Pectin–metronidazole prodrug bearing microspheres for colon targeting

The present study explored the potential of pectin–metronidazole (PT–ME) prodrug bearing microspheres for colon delivery. PT–ME prodrug was synthesized with different degree of substitution. The success of the synthesis was confirmed by spectroscopy. PT–ME microspheres and pectin microspheres bearing plain metronidazole were prepared using emulsion-dehydration technique. Microspheres were evaluated for shape and surface morphology, size distribution, entrapment efficiency and in vitro drug release in simulated gastrointestinal fluids (SGF). Microspheres prepared from PT–ME prodrug were not only exhibiting increased the drug entrapment efficiency, but the drug release at the upper part of GIT was also reduced as compared to pectin microspheres having physically entrapped drug. In vitro drug release studies were showing no drug release at acidic pH from microspheres prepared by drug polymer prodrug while pectin microspheres having physically entrapped drug showed almost or complete drug release. In vivo studies were also performed by assessing the drug concentration in various parts of the GIT at different time intervals which exhibited the potentiality of microspheres prepared from PT–ME prodrug as compared to pectin microspheres having physically entrapped drug. Hence, it can be concluded that microspheres prepared from PT–ME prodrug deliver the drug more efficiently to colon.