Permeation enhancers in the transmucosal delivery of macromolecules

The present article presents a compilation of information regarding various chemical permeation enhancers useful for transmucosal delivery of macromolecules. In the recent past, biotechnology has provided a great number of macromolecules for treatment of various disorders. With the rise in importance of macromolecules, especially proteins and peptides, an enormous volume of research on various novel routes of drug delivery has been carried out. Inspite of its giving the highest and fastest bioavailability, the parenteral route is not a preferred option, due to its inconvenience and the noncompliance of patients. Mucosal surfaces are the most common and convenient routes for delivering drugs to the body. However, macromolecular drugs such as peptides and proteins are unable to overcome the mucosal barriers and/or are degraded before reaching the blood stream. Transmucosal drug delivery with various bioavailability enhancers is receiving increasing attention as a possible alternative to parenteral delivery of macromolecules. Among the various bioavailability enhancers, chemical permeation enhancers have been most studied. Permeation enhancers reversibly modulate the permeability of the barrier layer in favor of drug absorption. Newer permeation enhancers like zonula occludin toxin, poly-L-arginine, chitosan derivatives etc have shown a significant increase in drug absorption through transmucosal routes without serious damage to the barrier layer. In particular delivery of macromolecules via the nasal and pulmonary routesusing newer permeation enhancers has emerged as a possible alternative to the parenteral delivery ofmacromolecules.