Small intestine gastrointestinal tract drug delivery

Numerous cases exist in the pharmaceutical field in which pH control of drug delivery may be beneficial. For example, the ability to store a drug molecule in the dry state in a polymer, to be released when the polymer reaches a region in the gastrointestinal tract that is characterized by a certain pH range (acidic in stomach, alkaline in the small intestine) has prompted a number of researchers to study pH-sensitive polymer gels as potential drug carriers for oral delivery [1-4]. 

The gastrointestinal tract is the most appropriate route for drug delivery. However, for enzymes, other proteins, and peptides, this way of administration is a new challenge for many research groups. Indeed, the parenteral route is often the preferred one for protein and peptide administration. Despite current opinion that the gut is completely impermeable to proteins and peptides, progress has recently been made in the elucidation of possible routes of penetration through the intestinal barriers. There is now evidence that small quantities of peptides and proteins can be absorbed intact from the gut. 

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