The aim of the present study is to develop colon targeted drug delivery systems for
metronidazole using sesbania gum as a carrier. Matrix, enteric coated and
compression coated tablets of metronidazole containing various proportions of
sesbania gum were prepared. All the formulations were evaluated for the hardness,
drug content uniformity, and were subjected to in vitro drug release studies. Matrix
tablets and enteric coated tablets of metronidazole released 41–71% and 25–28% of
the metronidazole, respectively, in the physiological environment of stomach and
small intestine depending on the proportion of sesbania gum used in the formulation.
Both the formulations failed to control the drug release within 5 hr. The compression
coated formulations (CS2) released less than 5% of metronidazole in the physiological
environment of stomach and small intestine. When the dissolution study was
continued in simulated colonic fluids, the compression coated tablet with 150 mg of
sesbania gum coat released another 76% of metronidazole after degradation by
colonic bacteria at the end of 12 hr.