Studies on absorption, distribution, metabolism, and excretion of a new macrolide antibiotic, SF-837. II. Pharmacokinetic studies on SF-837, MI, and M2 substances.

Abstract

The absorption studies by means of rat ligated loop technique indicated that this antibiotic was absorbed from the intestine most efficiently in the from of unaltered SF-837, in contrast to the low absorption of the metabolites. Most of the absorption occurred in the middle of small intestine of the rat where SF-837 was remarkably changed into M1. The metabolic pathway of this antibiotic was established as SF-837→M1→M2 from the urinary and biliary excretion study. The biliary to urinary excretion ratio of this antibiotic increased with decreasing dosage, as evidence by the infusion study. From comparative studies on portal and femoral vein infusion than the femoral vein infusion. This difference was in particular remarkable at a low speed of infusion (25-200μg/rat/hr).