Xenobiotic dietary absorption

Intestinal tract is the portal of entry for many xenobiotics such as orally administered pharmaceuticals, dietary constituents, and contaminants and even for ophthalmic drugs applied on the cornea and drained via uveoscleral tube to nasopharynx and gastrointestinal tract. Obviously it is difficult to find proper representative cells for the whole length of intestinal tract, but if the focus is on the absorption and metabolism, the colonic cell line Caco-2 has been used for decades and its characterization provides a good example of the difficulties associated with extrahepatic cell lines. Principally in food research area, several human cell lines, e.g., HIEC-6, H4, and H4-1, have been employed for bioaccessibility, absorption, and biotransformation studies [28, 29], but their application in toxicological research has been relatively unexplored. 

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