RT Journal Article
SR Electronic
T1 Isolation of two immunosuppressive metabolites after in vitro metabolism of rapamycin.
JF Drug Metabolism and Disposition
JO Drug Metab Dispos
FD American Society for Pharmacology and Experimental Therapeutics
SP 186
OP 191
VO 20
IS 2
A1 Christians, U
A1 Sattler, M
A1 Schiebel, H M
A1 Kruse, C
A1 Radeke, H H
A1 Linck, A
A1 Sewing, K F
YR 1992
UL http://dmd.aspetjournals.org/content/20/2/186.abstract
AB Rapamycin was incubated with human liver microsomes and an NADPH regenerating system, the metabolites were purified by semipreparative HPLC, and their structures were elucidated by direct chemical ionization and FAB-MS. At least six fractions were isolated containing rapamycin metabolites, indicating that rapamycin is metabolized by the human liver cytochrome P-450 system. One of these metabolites was identified as 41-O-demethyl-rapamycin. A second metabolite was hydroxylated in a yet unknown position. These two metabolites retained immunosuppressive activity in a phytohemagglutinin-stimulated human lymphocyte assay with IC50S of 1 and 1.5 nmol/liter, respectively. Rapamycin was metabolized by rat small intestinal microsomes to at least two metabolites, indicating extra-hepatic metabolism of rapamycin.