Percutaneous Absorption of C14-Labeled Triamcinolone Acetonide

Abstract

Studies of percutaneous absorption of C¹⁴-labeled triamcinolone acetonide in two normal subjects revealed urinary excretion of 2.3% and 0.6% of applied steroid. These preliminary findings indicate that triamcinolone penetrates normal skin sites in approximately the same quantities as those reported previously for cortisone and hydrocortisone. Studies of the absorption of C¹⁴-labeled triamcinolone acetonide through stripped skin sites showed far slower penetration than that demonstrated previously for hydrocortisone alcohol. For example, 20% or more of applied triamcinolone was still demonstrable at test sites 20-24 hours after application, while for hydrocortisone 20% of applied material remained only 1-2½ hours after application. Investigations of the inhibitory effects of high tissue concentration gradients and vasoconstriction induced by triamcinolone are described for the subsequent absorption of C¹⁴-labeled triamcinolone and testosterone-4-C¹⁴ at stripped skin sites. Factors important to the increased potency of triamcinolone—in the absence of enhanced absorption—have been discussed. Emphasis has been placed on the necessity for further quantitative absorption data for derivatives of hydrocortisone and prednisolone in view of recent reports of adrenal cortical suppression following the topical use of adrenal steroid compounds.