A NEW CRYSTALLIC FORMULA OF 7 - (1 ALPHA, 5 ALPHA, 6 ALPHA-6-AMINO-3-AZABICYCLO [3.1.0] -EXERICYL) -6- FLUORO- 1- ) -1,4-DIHYDRO-4-OXO-1,8-NAPHTIRIDINE-3-CARBOXYLIC ACID, METHANESULPHONIC ACID SALT
7 - ([1,5,6] -6-Amino-3-azabicyclo [3.1.0] hex-3yl) -6-fluoro- 1- (2,4- difluorophenyl) 4-oxo-1,8-naphthyridine-3-carboxylic acid, the methanesulfonic acid salt is used as a stable antibacterial agent for formulation.