Gastrointestinal Bioadhesive Drug Delivery Systems and Their Applications

There are many routes of drug delivery but the gastrointestinal route is the oldest and most used due to ease of administration and patient compliance. However, this route has shortcomings such as hepatic first-pass metabolism and enzymatic degradation in the gastrointestinal tract (GIT), which is a hindrance to the absorption of most groups of drugs. The mucosa of the GIT can be optimized for drug delivery by the use of adhesive dosage forms since the mucosa has a rich blood supply and it is relatively permeable. In the design of drug delivery systems, bioadhesion infers attachment of a drug carrier system to a specific epithelial tissue. A bioadhesive drug delivery system prolongs the retention time of the dosage form at the site of absorption, facilitates intimate contact of the dosage form with the absorption surface, and leads to better therapeutic outcomes of the drug. This chapter is on gastrointestinal drug delivery systems and their applications.