DETERMINATION OF HOMOSULFANILAMIDE HYDROCHLORIDE (SULFAMYLON HYDROCHLORIDE) WITH OBSERVATIONS ON ITS ABSORPTION IN DOGS AND MAN

¹ Sterling-Winthrop Research Institute, Rensselaer, N. Y.

A colorimetric method for the determination of homosulfanilamide hydrochloride (Sulfamylon hydrochloride) in blood is presented. The compound is allowed to react with sodium -naphthoquinone sulfonate in alkaline solution, and the yellow condensation product is extracted by means of methyl n-amyl ketone. The optical density of the extracts, measured at 420 mµ, is proportional to the amount of Sulfamylon hydrochloride present. The method has been applied to the study of blood levels in dogs and men following oral or parenteral administration. Oral doses of 600 mgm./kgm. to doga give peak blood levels of about 10 mgm. per cent at from two to three hours after administration. Absorption and excretion and/or metabolism are rapid, and it would be necessary to give doses about every four or five hours in order to maintain this level.

Doses of 150 mgm./kgm. given every four hours serve to hold the blood level at about 4 mgm. per cent with occasional values as high as 6 mgm. per cent. By intravenous infusion of 600 mgm./kgm. in an isotonic solution (3.8 per cent, pH 7.4), within 30 minutes, blood levels as high as 100 mgm. per cent may be achieved without causing death although there is a marked fall in blood pressure; it requires five to six hours to reduce the concentration again to 0-3 mgm. per cent. Subcutaneous infusion of 600 mgm./kgm. in a solution of the same composition gives a peak blood level about the same as following an equal oral dose, but the return to zero concentration is much less rapid.