Stabilization of pyrido{8 3,2-a{9 phenoxazine compounds

摘要

Stabilized solutions of 1-hydroxy-5-oxo-5H-pyrido-[3,2-a]-phenoxazine-3-carboxylic acid (I) and of 1,5-dihydroxypyrido-[3,2-a]phenoxazine-3-carboxylic acid (II) are provided. The solutions contain a stabilizer selected from the group consisting of ascorbic acid, isoascorbic acid and water-soluble salts thereof. The solutions optionally contain an auxiliary stabilizer selected from the group consisting of sodium sulfite, sodium metasulfite and N-acetyl-L-cysteine and may also contain a solubilizer.