RT Journal Article
SR Electronic
T1 METABOLISM OF PROPIONYL ERYTHROMYCIN LAURYL SULFATE
JF Drug Metabolism and Disposition
JO Drug Metab Dispos
FD American Society for Pharmacology and Experimental Therapeutics
SP 155
OP 163
VO 3
IS 3
A1 PATRICK J. MURPHY
A1 TERRY L. WILLIAMS
A1 ROBERT E. McMAHON
A1 FREDERICK J. MARSHALL
YR 1975
UL http://dmd.aspetjournals.org/content/3/3/155.abstract
AB The absorption. excretion, and metabolism of propionyl erythromycin ( PE) has been studied in the rat. The major routes of metabolism of PE are ester hydrolysis and N-demethylation. The rates of these two reactions have been examined in vivo using radiolabeled PE. The plasma half-life of the ester is 5.5 hr. The correlation of blood levels of radioactivity with 14C02 production mdicates that the ester is continually hydrolyzed after absorption. The half-life of the dimethyl-amino moiety of the desosamine sugar is estimated at 1.5 hr. This relatively short half-life compared to that of the ester is supported by the fact that at 3.5 hr after dosing there is twice as much desmethyl-PE in plasma as PE. After oral administration of either 14C-PE or 14C-erythromycin. 70% of the radioactivity is absorbed in 6 hr. The major route of excretion is via bile. Approximately 40% of the absorbed dose is excreted in bile in the first 6 hr after dosing. Tissue levels of radioactivity after administration of 14C-erythromycin or 14CPE indicate that PE or a metabolite accumulates in the tissue during chronic dosing. whereas erythromycin-related levels are similar after single or multiple doses. Copyright © 1975 by The American Society for Pharmacology and Experimental Therapeutics