["Targeted delivery" in the gastrointestinal tract].

Drug delivery to the intestine has become attractive to researchers with the main interest in the delivery of peptide drugs to the large intestine and the treatment of colonic diseases. There are currently 4 strategies that are pursued to reach colon specificity: 1. by relying on the pH difference between the small and the large intestine; 2. by exploiting the enzymatic activity of the colonic microflora; 3. by relying on the relatively constant small intestinal transit time and 4. by taking advantage of the increase of the luminal pressure in the colon due to strong peristaltic waves. Drug delivery to the small intestine may be achieved by pH-controlled and time-controlled drug release mechanisms. Diffusion-controlled systems allow drug delivery over the entire gastrointestinal tract.