Oral colon delivery: rationale and time-based drug design strategy

Increasing efforts have recently been spent onto the accomplishment of oral colon targeting. Indeed, this has been related to a number of local as well as systemic highly interesting applications, such as a more effective and tolerable therapy of inflammatory bowel disease (IBD), the pharmacological prevention of colorectal adenocarcinoma, and a possible improvement in the oral bioavailability of peptide and protein drugs. For the purpose of colon targeting, a variety of delivery technologies have been described, which rely on typical variation patterns shown by selected physiological parameters throughout the gastrointestinal tract. In particular, this article is focused on time-based formulation approaches that exploit the relative consistency in the small intestinal transit time (SITT) of dosage forms.