Ciprofloxacin salt and salt co-crystal with dihydroxybenzoic acids

Abstract

The crystal structure of two multi-component crystals of ciprofloxacin [systematic name: 1-cyclopropyl-6-fluoro-4-oxo-7-(piperazin-1-yl)quinoline-3-carboxylic acid], a fluoroquinolone antibiotic, namely, ciprofloxacin 2,6-dihydroxybenzoate salt, C17H19FN3O3 +·C7H5O4 −, (I), and ciprofloxacin hydrochloride–3,5-dihydroxybenzoic–water (1/1/1), C17H19FN3O3 +·Cl−·C7H6O4·H2O, (II), were determined. In (I) and (II), the ciprofloxacin cations are connected via head-to-tail N—H...O hydrogen bonding. Both structures show an alternating layered arrangement between ciprofloxacin and dihydroxybenzoic acid.

Improving aqueous solubility of ciprofloxacin: three different stoichiometric hydrated salt forms with oxalic acid

“…This form notably increases the solubility of ciprofloxacin in solution media, including water and buffer. 18 Recently, many attempts have been made to find an alternative ciprofloxacin salt, such as CIF salt with a linear dicarboxylic acid 19 and benzoic acid derivatives, 20,21 and theoretical calculations have been applied based on partial least squares regression (PLS) for predicting the multicomponent crystals of ciprofloxacin. 22 In addition, norfloxacin, one of the fluoroquinolone family, has a similar chemical structure and behavior salt formation with CIF reported 12 new co-crystal/salts with six co-formers.…”