Objective: A major challenge in targeting orally administered drugs to colon is their passage
through the long gastrointestinal path comprising highly variant conditions in terms of pH, viscosity,
gut motility and microbial flora. Approaches to pH controlled release and microbially triggered release
have proved to be successful in achieving colon targeting only to a partial extent.
Methods: In an attempt to improve targeting, both these approaches have been combined together with
the approach of liquisolid technology which, hitherto, remains unexplored for colon targeting. The
combination of these three approaches is being reported for the first time to achieve colon targeting
along with a burst release of a Biopharmaceutical Classification System (BCS) Class IV drug at the
target site. pH controlled polymer, Eudragit® S-100 was used to prevent the release of sulfasalazine in
the gastric region while microbially triggered polymers, pectin and guar gum were used to ferry the
system through the intestinal region.
Results: Liquisolid formulation was designed to provide a burst release of sulfasalazine in colon on the
digestion of polysaccharide coating.
Conclusion: The results support the premise that the combination of pH sensitive, microbially triggered
polymers and liquisolid formulation technique appears to be a pragmatic approach for colonic delivery
of orally administered drugs.