Enhancement of lymphatic transport of lutein by oral administration of a solid dispersion and a self-microemulsifying drug delivery system.

Lutein is located in the macula lutea in the human eye. Since humans cannot synthesize lutein de novo, it must be digested as food. Some studies including our previous study showed very low absorption of lutein after oral administration. These studies also suggested that the absorption route of lutein from the small intestine involves not only the blood but also the lymph. The aim of this study was to clarify the transfer of lutein into lymph and the tissue distribution after oral administration of a solid dispersion (SD) and a self-microemulsifying drug delivery system (SMEDDS) for improvement of the absorption. We used thoracic lymph-cannulated rats. It was shown that the plasma concentrations of lutein in the SD and SMEDDS groups were increased compared with that in the powder group. The absorption of lutein after oral administration of each formulation was clearly evaluated by its cumulative amount in lymph. Our data clearly showed that lutein is transferred into the lymph stream from the small intestine.