Absorption, Excretion, and Biotransformation of Dimethyl Sulfoxide in Man and Miniature Pigs After Topical Application as an 80% Gel

Abstract

The absorption, excretion, and biotransformation of dimethyl sulfoxide (DMSO) 80% gel, DEMASORB®, was studied in man and in miniature pigs. DMSO 80% gel (15 cc, t.i.d.) was applied topically to the elbows of human subjects and allowed to remain there for 30 minutes after each application. Under these conditions, daily absorption of DMSO 80% gel ranged from 25 to 40% of the total dose. DMSO 80% gel (15 g, t.i.d.) was completely absorbed within 4 hours after application to the shaved backs of miniature pigs. Both man and miniature pig transformed DMSO to dimethylsulfone (DMSO 2 ) and dimethylsulfide (DMS). DMSO and DMSO 2 were excreted in the urine, whereas DMS was eliminated in the expired air. In man, the relative amounts of DMSO and DMSO 2 in the plasma were similar to those found in the urine. The biological half-life of DMSO 2 in both the plasma and urine of man was 2.5 to 3 days. Urinary excretion of DMSO plus DMSO 2 ranged from 9 to 35% of the dose in both man and miniature pigs; only 1.6% of the dose was present in the feces of miniature pigs. Whereas DMSO 2 was the main excretory product in the urine of man, DMSO was the major component in the urine of miniature pigs.