Hydrogen bonded networks in hydrophilic channels: crystal structure of hydrated Ciprofloxacin Lactate and comparison with structurally similar compounds

Ciprofloxacin Lactate {4-(3-carboxy-1-cyclopropyl-6-Ruoro-1-4-dihydro-4-oxo -7-quinolinyl-)-1-piperazinium-lacate- water(1/1/1.5)} (C20H24N3O6F1.5H2O) belonging to the family of fluoroquinolone antibacterial agents with wide s pectrum activity has been studied using single crystal X-ray diffraction te chniques. The crystal structure has channels running along crystallographic b-axis with pi -stacks of Ciprofloxacin moieties linked through water mole cules. A ten-membered hydrogen bonded pattern formed by centrosymmetrically related lactate and water molecules fill the center of the channel. The mo lecular assembly viewed down the b-axis depicts an infinitely extended open framework channels with the major diameter of about 10.60 Angstrom and min or diameter of 4.79 Angstrom. The structure also has a C-H . . .F intramole cular interaction and an intramolecular hydrogen bond. Analysis of the stru ctures containing 7-piperazin-1-oyl-quinolin-4(1H)-one moiety using the Cam bridge Structural Database reveals that a majority of the structures show t he propensity to form channels via pi...pi interactions. Also, a detailed c omparative study with the structure of magnesium sulfate adduct of ciproflo xacin shows that such interactions lead to similar molecular assemblies. (C ) 2001 Elsevier Science B.V. All rights reserved.