Studies on Absorption of Eutectic Mixture. I. A Comparison of the Behavior of Eutectic Mixture of Sulfathiazole and that of Ordinary Sulfathiazole in Man.

1) Sulfathiazole forms eutectic mixtures with urea, l-ascorbic acid, acetamide, nicotinic acid, nicotinamide, or succinimide. It was observed that a eutectic mixture of sulfathiazole and urea produces a microcrystalline suspension of sulfathiazole in water. 2) Sulfathiazole in a eutectic mixture with urea shows higher absorption and excretion after oral administration than ordinary sulfathiazole. 3) Since urea does not possess solubilizing action on sulfathiazole and also it does not enhance absorption of the drug physiologically, the accelerated absorption or excretion must be attributed to the physical state of sulfathiazole in its eutectic mixture with easily soluble compound, such as urea. 4) It is assumed that this new form of preparation will give a means of adjusting therapeutic effect of medical compounds.