Radioprotective Agents: Results with S-(3-Amino-2-Hydroxypropyl) Phosphorothioate, Amidophosphorothioate, and Some Related Compounds

Abstract

Two S-phos-phorylated thiols, dilithium S-(3-amino-2-hydroxypropyl) phosphorothioate and S-(2-aminopropyl) phosphorothioate, have been shown to be good radioprotectors when given to mice before irradiation with X-rays. The observed dose-reduction factors were 2.16 and 1.86, respectively. The reference substance, cysteamine, gave a dose reduction of 1.84. There is a significant difference in radioprotective effect of S-(3-amino-2-hydroxypropyl) phosphorothioate if given in solution at pH 10 or at pH 7. A new class of radioprotectors, diammonium amidophosphorothio-ateanddiammonium thiodiamidodiphosphate, gave dose-reduction factors of 2.30 and 2.16, respectively, at molar doses lower than that of cysteamine by a factor of 10 to 20.