Mucus barrier

In order to achieve and sustain therapeutic blood levels by peroral administration of drugs, several hurdles have to be overcome. Besides well-known barriers such as enzymatic degradation, dissolution problems, mucus barrier and others,... 

Strategies to overcome the mucus barrier focus mainly on the use of mucolytic agents such as dithiothreitol (DTT) and A-acetyl cysteine (NAC). So far, however, results were rather disappointing in improving accessibility to the intestinal crypts for somatic gene therapy (Sandberg et. al. 1994). 

The enterocytes of the small intestine can be isolated and used for study of intracellular aspects of intestinal lipid transport like triglyceride synthesis [52]. The disappearance of the mucus barrier during isolation of the epithelial cells results in plasma membrane disintegration and loss of cellular integrity when the cells are exposed to bile salts. As is the case for brush border vesicles, the system of isolated cells does not allow study of interaction between enterocytes and lipids dispersed in a form that resembles physiological conditions, i.e. solubilized in mixed bile salt micelles. 

Wang, Y.Y., Lai, S.K., Suk, J.S., Race, A., Cone, R., Hanes, J. Addressing the PEG mucoadhesivity paradox to engineering nanoparticles that slip through the human mucus barrier. Angew. Chem. Int. 47, 9726-9729 (2008)... 

Corazziari E. (1999) Intestinal mucus barrier in normal and inflamed colon. J Pediatr Gastroenterol Nutr 48 Suppl 2 S54-S55. 

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