Drug Delivery: Plant Lectins as Bioadhesive Drug Delivery Systems

Selective targeting of drugs to the proposed site of action provides therapeutic advantages such as reduced toxicity and smaller dose levels. Despite a huge progress made in drug design and delivery systems, many challenges still have to be solved. Small therapeutic drugs always have the potential to pass into the kidneys and be excreted from the body. The use of macromolecular constructs (carriers) that allow longer circulation times, contribute to improved chemical functionality and more precise drug delivery is an attractive alternative option. Bioadhesive systems which will utilize intense contact to increase the drug concentration gradient could be an attractive approach. Because of their specific carbohydrate-binding, lectins can interact with glycoconjugates present on the epithelial cells that line all of the organs exposed to the external environment. The unique carbohydrate specificities of plant lectins can facilitate mucoadhesion and cytoadhesion of drugs. As immunostimulatory molecules with an adjuvant effect plant lectins can also be employed in vaccine development.