Anhydrous crystal of 4-carbamoyl-1-beta-D-ribofuranosyl imidazolium-5-olate

摘要

Anhydrous crystals of 4-carbamoyl-1- beta -D-ribofuranosyl imidazolium-5-oleate are disclosed. The crystals possess (1) water content of 0.5% by weight or less (the Karl Fisher method), and (2) specific IR spectrum absorption peaks in the neighborhoods of 3580, 1852, 1630, 1575, and 1554 cm<-><1>. They are stable against heat and high humidity conditions and can easily be manufactured by using ethanol. The compound has superior immuno-suppressing activity and is thus made into preparations for oral administration.