PT - JOURNAL ARTICLE AU - Redondo, P. A. AU - Álvarez, A. I. AU - Garcia, J. L. AU - Larrodé, O. M. AU - Merino, G. AU - Prieto, J. G. TI - Presystemic Metabolism of Albendazole: Experimental Evidence of an Efflux Process of Albendazole Sulfoxide to Intestinal Lumen DP - 1999 Jun 01 TA - Drug Metabolism and Disposition PG - 736--740 VI - 27 IP - 6 4099 - http://dmd.aspetjournals.org/content/27/6/736.short 4100 - http://dmd.aspetjournals.org/content/27/6/736.full SO - Drug Metab Dispos1999 Jun 01; 27 AB - Albendazole (ABZ) presystemic clearance was studied in rat by perfusion of a 25 μM ABZ solution in isolated intestinal loops. Significant secretion of the active metabolite, ABZSO, into the lumen was observed. The metabolite was also present in mesenteric blood. After 30 min of intestinal perfusion, 64% of the ABZ dose had disappeared from lumen. The total amount of ABZSO measured was 0.341 ± 0.04 nmol/cm with 0.176 ± 0.03 nmol/cm in mesenteric blood. The metabolite secretion to intestinal lumen was 0.165 ± 0.05 nmol/cm. Intestinal sulfoxidation was induced by repeated administration of ABZ and ABZ coadministered with surfactants, especially polysorbate 80. The enantioselectivity of the in vitro intestinal sulfoxidation of ABZ showed that the relative contribution of P-450 and flavin-containing monooxygenase was quite similar, but after the induction by ABZ coadministered with polysorbate 80, the cytochrome P-450 system contribution was significantly increased. The appearance of ABZSO in mesenteric blood clearance was also increased under these conditions. The American Society for Pharmacology and Experimental Therapeutics