1998 Volume 21 Issue 7 Pages 747-751
The effects of fatty acid sucrose esters on membrane lipid dynamics and ceftibuten transport by rat intestinal brush-border membrane vesicles (BBMV) were examined to clarify the differences in the action of mono- and poly-acyl sucrose esters on the drug transport. Fatty acid sucrose mono-acyl ester (SS) inhibited ceftibuten transport by BBMV similar to the action of polyoxyethylene sorbitans (Tweens), while fatty acid sucrose polyacyl ester mixtures (F-160 and F-140) did not affect the drug transport by BBMV. SS but not F-160 and F-140 caused an increase in the anisotropy of 1, 6-diphenyl-1, 3, 5-hexatriene (DPH)- and 1-(4-trimethylammonium-phenyl)-6-phenyl-1, 3, 5-hexatriene iodide (TMA-DPH)-labeled BBMV in a concentration-dependent manner. Thus, the uptake of ceftibuten by BBMV was strongly correlated with the lipid fluidity of BBMV, in the outer layer and in the inner hydrophobic regions; however, there was no strong correlation between the membrane lipid fluidity and the drug uptake by BBMV. The micelle size and the size distribution of F-160 and F-140 were larger and more widely dispersed, respectively, compared to those of SS and Tweens. These results suggest that the effects of fatty acid sucrose esters on ceftibuten transport by BBMV are related to the dispersion parameter of these pharmaceutical adjuvants.