Theophylline magnesium salicylate, a new xanthine compound.

Interaction of 1 mole of magnesium salicylate and 2 moles of theophylline in water precipitated a crystalline compound, identified as theophylline magnesium salicylate pentahydrate from analytical and supportive physicochemical data. Similarly, barium salicylate and theophylline produced theophylline barium salicylate. No precipitates were formed with calcium salicylate or strontium salicylate under the same conditions. Theophylline magnesium salicylate is not a mixture of components and differs in composition from the known theophylline calcium salicylate dihydrate. Unlike the latter compound, it is not alkaline.