Metabolism of propionyl erythromycin lauryl sulfate. II. Fate of the lauryl sulfate moiety in the rat and man.

The absorption, excretion, and metabolism of [1-14C]lauryl sulfate as either the sodium or propionyl erythromycin salt has been studied in the rat and man. In the rat 88% of the radiolabel from propionyl erythromycin [1-14C]lauryl sulfate was excreted in the urine in the 24-hr period following a single oral dose. More than 95% of the radiolabel was excreted as the metabolite butyric acid 4-sulfate. This metabolite was shown to be derived from carbons 1-4 of the lauryl sulfate moiety. There was no evidence of sulfate cleavage in the rat. In man 51-59% of the administered ratioactivity was recovered in the urine. The major excretion product was butyric acid 4-sulfate accounting for approximately 95% of urinary radioactivity. The remainder was unchanged lauryl sulfate. A significant portion of the radiolabeled propionyl erythromycin lauryl sulfate was converted to 14CO2 indicating that the sulfate linkage was cleaved. A minimum value of 9-16% of the dose was metabolized in this manner.