The archaeolipids (
lipids extracted from archaebacterias) are non saponificable molecules that form self sealed mono or bilayers (archaeosomes-
ARC). Different to
liposomes with bilayers made of conventional
glycerophospholipids, the bilayer of
ARC posses a higher structural resistance to physico chemical and enzymatic degradation and surface hydrophobicity. In this work we have compared the binding capacity of
ARC exclusively made of archaeols containing a minor fraction of sulphoglycophospholipids, with that of
liposomes in gel phase on M-like cells in vitro. The biodistribution of the
radiopharmaceutical (99m)Tc-DTPA loaded in
ARC vs that of
liposomes upon
oral administration to Wistar rats was also determined. The fluorescence of M-like cells upon 1 and 2h incubation with
ARC loaded with the hydrophobic
dye Rhodamine-PE (Rh-PE) and the hydrophilic
dye pyranine (HPTS) dissolved in the aqueous space, was 4 folds higher than upon incubation with equally labeled
liposomes. Besides, 15% of Rh-PE and 13 % of HPTS from
ARC and not from
liposomes, were found in the bottom wells, a place that is equivalent to the basolateral pocket from M cells. This fact suggested the occurrence of transcytosis of
ARC. Finally, 4 h upon
oral administration,
ARC were responsible for the 22.3 % (3.5 folds higher than
liposomes) shuttling of (99m)Tc-DTPA to the blood circulation. This important amount of radioactive marker in blood could be a consequence of an extensive uptake of
ARC by M cells in vivo, probably favored by their surface hydrophobicity. Taken together, these results suggested that
ARC, proven their adjuvant capacity when administered by parenteral route and high biocompatibility, could be a suitable new type of nanoparticulate material that could be used as adjuvants by the oral route.