Guar Gum Microspheres of 5-Fluorouracil for Colon Targeting

The purpose of this investigation was to prepare and evaluate the colon-specific guar gum microspheres of 5fluorouracil for the treatment of colon cancer. Guar gum microspheres were prepared by water-in-oil emulsification followed by cross-linking method using glutaraldehyde as a cross linking agent. Different ratios of drug and polymer (1:3 to 1:5), emulsifier concentrations (1%-3% w/v) and stirring speeds (1000–3000 rpm) were tried and the effects of these variables on drug delivery were studied. Particle size, shape, and surface morphology were significantly affected by drug: Polymer ratio, emulsifier concentration (Span 80) and stirring rate. Guar gum microspheres were evaluated for swellability, percentage drug entrapment, and in vitro drug release in simulated gastrointestinal fluids (SGF). The in vitro drug release studies of the formulations were also performed in simulated colonic fluid in the presence of 2% rat cecal content. The release profile of 5-FU from Guar gum microspheres was pH dependent. In acidic medium, the release rate was much slower; however, the drug was released quickly at pH 7.5. Guar gum microspheres showed adequate potential in achieving local release of drug in in-vitro release studies, It is concluded from the present investigation that Guar gum microspheres are promising controlled release carriers for colon-targeted delivery of 5-FU.