THE ENHANCING MECHANISM OF CAPRIC ACID (C10) FROM A SUPPOSITORY ON RECTAL DRUG ABSORPTION THROUGH A PARACELLULAR PATHWAY

Capric acid (C10) enhanced the absorption of cefoxitin sodium in a con centration-dependent manner following the rectal administration as a s uppository in rats, Tile optimal concentration of C10 was 13%. CIO adm inistered as a suppository also reduced rectal membrane resistance (R- m), showing that the above enhancing effect was induced by widening th e paracellular pathway. Both the enhancing Effect. on the absorption a nd the reducing effect on R-m were inhibited by W7, an inhibitor of my osin light chain kinase, These results supported that, as shown in the ill vitro Caco-2 cell sg stem, tile C10 effect on the paracellular pa thway is due to activating the contraction of Ca2+-calmodulin-dependen t actin filament.