The development of formulations with modified release of the drug
substances targeting different segments of the gastrointestinal tract is an ongoing
challenge for the scientist in the field of drugs. Current manufacturing technologies are
mainly focused on delayed release so that the release does not start before the
formulation reaches the colon. Other technologies are based on time-delayed active
substance release with a predetermined lag time, on time-delayed controlled release
systems with enzymes, and on pressure controlled release systems. The release of
medicinal substances incorporated into colonic-release microparticulate systems is
dependent on pH, on the system's gastrointestinal transit time or on the microbial and
enzymatic load of the colon. Colonic release micro/nanoparticulate systems based on
natural polymers led to significant results. Recent research has shown that the most
effective colon-specific micro/nanoparticulate systems are those combining several drug
release principles.
Keywords: Colon targeted drug delivery, modified release, bioavailability,
inflammatory bowel disease, oral dosage forms, ulcerative colitis, polymeric
prodrugs, polysaccharides, micro/nanoparticulate systems.
