Development of novel pH-responsive dual crosslinked hydrogel beads based on Portulaca oleracea polysaccharide-alginate-borax for colon specific delivery of 5-fluorouracil

This study aimed to explore the colon targeting potential of novel polymeric beads encapsulating the anticancer drug 5-fluorouracil (5-FU) prepared utilizing Portulaca plant mucilage. Polysaccharide gel matrix was prepared by using ionotropically gelled mixture of biopolymers sodium alginate and Portulaca polysaccharide, which was isolated from leaves of Portulaca oleracea and was then cross-linked with borax for effective control of drug release in colon. Size and morphology of the prepared beads were characterized using scanning electron microscope (SEM). Other parameters evaluated were drug encapsulation efficiency and cumulative in vitro drug release using rat caecal content and different pH media to simulate the gastrointestinal tract. This novel pH responsive biopolymer provides an option to use plant-based mucilage for colon-specific drug delivery. These natural polysaccharides can form hydrogels and they have an added advantage of being categorized under GRAS (generally recognised as safe) with additional benefits of biocompatibility, biodegradability and specificity towards drug targeting to colon.