Modification of intestinal absorption of drugs by lipoidal adjuvants.

The use of various lipids for the modification of intestinal absorption of lipophilic, hydrophilic, or macromolecular drugs is reviewed. The influence of lipids on drug absorption varies with the structure and physical state of incorporated lipids. The mechanisms of drug absorption across the intestine, that involve lipids in the state of emulsions, liposomes, and micelles, are discussed. The use of fusogenic lipids in the micellar state can be most effective in enabling the absorption of poorly absorbed drugs, such as antibiotics and macromolecules. Moreover, within the gastrointestinal tract their promoting ability is greatest in the colorectal region. Fusogenic lipids are also useful for selective lymphatic delivery of drugs with a macromolecular carrier.