ABSTRACT
Rapid developments in biotechnology have posed new challenges for pharmaceutical research scientists to develop peptide and protein drugs. Although these peptide and protein drugs are highly potent and specific in their physiological actions, they are in general difficult to administer orally. The mucosal layer, comprising the lumenal surface of the small intestine, is responsible for the digestive and absorptive functions of the small intestine. The mucosal surface area is much larger than predicted for a simple cylinder. Circular folds account for this amplification. The absorptive cell basolateral membrane rests on the lamina propria. The basolateral membrane is different from the apical membrane. It has a low proteinlipid ratio and is thinner and more permeable than the apical membrane. Proteins are one of the major naturally occurring organic compounds, and they constitute much of animal and plant tissue. Proteins are the most abundant components of cells.
