Lipid as a Vehicle/Carrier for Oral Drug Delivery

Abstract

The drug administered by an oral route has to withstand a harsh environment of gastrointestinal media, absorb through intestinal epithelium and circumvent first-pass metabolism in liver before reaching portal blood circulation. Moreover, hydrophobic drug molecules offer challenges for formulation with respect to their solubility and hence bioavailability. Various approaches have been developed to overcome this barrier. One of them is the use of lipids in formulation. Incorporation of the drug in lipids can result in increased solubility, absorption and thereby enhanced bioavailability. Intestinal lymphatic route of absorption has also been explored for increasing bioavailability of hydrophobic drug moieties. In this chapter, we have discussed the pathway of lipid digestion in the human body as well as the mechanism of lipid particles upon oral administration. The various lipid formulations developed and the excipients used in the formulations have also been described. The importance of lipid chain length and the effect of food in increasing the bioavailability of drug is discussed. The lymphatic pathway of lipid carriers has also been discussed.