Drug Delivery Technologies for Upper Small Intestinal Window: A Review

Oral bioavailability of some drugs can be limited by the residence time of pharmaceutical formulation in the upper gastrointestinal tract. Gastric emptying plays an important role in the dynamics of drug absorption and can lead to variable and unpredictable bioavailability. And it becomes more critical for drugs which are exclusively absorbed in the upper small intestine or in a limited segment of the intestine “regional absorption”. To overcome this restriction and to increase the bioavailability of these drugs, controlled drug delivery systems with a prolonged residence time in the stomach can be used. Approaches for achieving prolonged residence times of the devices in the upper part of the gastrointestinal tract include the use of bio-adhesive, size increasing, and floating drug delivery systems.