Linagliptin Impurity 1

(+)-(R)-9-Fluoro-2, 3-dihydro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-7H-pyrido[1, 2, 3-de]-1, 4-benzoxazine-6-carboxylic acid ; (R)-(+)-Ofloxacin ; D-Ofloxacin ; Ofloxacin R-Isomer ; Levofloxacin D-Isomer ;