THE EFFECT OF MONOMERS AND OF MICELLAR AND VESICULAR FORMS OF NONIONIC SURFACTANTS (SOLULAN-C24 AND SOLULAN-16) ON CACO-2 CELL MONOLAYERS

Measurements of transepithelial electrical resistance (TEER), the MTT -dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) test and m onitoring of poly(ethylene glycol) (PEG) transport have been used to s tudy the effects of the non-ionic surfactants Solulan C24 and Solulan 16, either free in solution or as an integral part of niosome bi-layer s, on intestinal epithelial cells from man (Caco-2 cell monolayers). T he effects on epithelial integrity and on the transport of the hydroph ilic drug metformin depend on the concentration of the surfactants. At concentrations above 1% the effect on TEER of the surfactant in nioso mal form and free in solution were equivalent whereas cell viability w as preserved to a higher concentration of Solulans when the Solulans w ere present in the niosomal form. It was concluded that the toxic effe ct of niosomes arises from free surfactant present in the niosome susp ension.