Association with oleic acid vesicles enhances manganese III mesoporphyrin absorption and biliary elimination in rats

OBJECTIVE. TO determine whether the association of manganese III mesoporphy rin (MnMeso), an oral MR contrast agent, to oleic acid (OA) vesicles will i mprove absorption and delivery of MnMeso to the liver. METHODS. MnMeso or MnMeso-OA vesicle suspension was intraduodenally adminis tered to rats and the time course of MnMeso concentration in plasma, bile, and intestinal solution was determined. Tissue concentrations of MnMeso in the liver were also determined. RESULTS. Association of MnMeso to OA reduced the time it took to reach one- half absorption maximum, TC50, and enhanced the rate and the extent of bili ary elimination of this contrast agent. In addition, the results obtained f rom dose-titration studies indicate that MnMeso-OA vesicle complex may enha nce MnMeso accumulation in the liver, observed as a lower dose required to reach equivalent tissue concentration. Taken together, complexion to OA ves icles may provide rapid absorption, enhanced liver accumulation, and effici ent elimination of MnMeso, CONCLUSIONS. Association with OA vesicles may enhance the rate of MnMeso ab sorption and biliary excretion while promoting the extent of liver accumula tion of MnMeso in rats. This strategy may provide a means to provide safe a nd effective use of MnMeso as an MR contrast medium.