The objective and timing of drug disposition studies, appendix II. Plasma concentrations of oxyphenbutazone in dogs given oxyphenbutazone or the calcium or sodium salts of its phosphate ester.

Abstract

Plasma levels of oxyphenbutazone were measured in beagle dogs following oral administration of oxyphenbutazone and salts of oxyphenbutazone phosphate. Dosage with sodium and calcium salts of oxyphenbutazone phosphate produced higher oxyphenbutazone plasma levels than dosage with oxyphenbutazone itself. Oxyphenbutazone phosphate was not detected in plasma following oral dosing with salts of oxyphenbutazone phosphate but was found in plasma following intramuscular administration of oxyphenbutazone phosphate sodium salt. A metabolite, oxyphenbutazone glucuronide, was found in plasma of dogs following administration of either oxyphenbutazone or salts of oxyphenbutazone phosphate.