Pharmaceutical salts of ciprofloxacin with dicarboxylic acids

Diversity of crystal structures and physicochemical properties of ciprofloxacin and norfloxacin salts with fumaric acid

“…In this research, we report crystal structures, physicochemical properties, thermodynamic stability and solubility of the fumarate salts of ciprofloxacin and norfloxacin with different stoichiometry values and hydration levels. Although ciprofloxacin fumarate monohydrate (1 : 1 : 1) and ciprofloxacin hemifumarate sesquihydrate (1 : 0.5 : 1.5) have been described earlier, 10,12 norfloxacin salts with fumaric acid are reported for the first time. It has been found that each fluoroquinolone can form three distinct salt forms with fumaric acid, namely two forms with a 1 : 1 drug/acid stoichiometry and one form with a 1 : 0.5 drug/acid stoichiometry.…”

Novel drug delivery systems to combat antimicrobial resistance

“…In the case of poorly soluble antibiotics, modification to a salt form of the drug with an organic counter ion will improve its solubility and bioavailability. Additionally, the solubility of an antibiotic can be controlled based on pH [31]. However, as a hydrochloride salt form, it shows slow dissolution in stomach at acidic pH due to common ion effect [31].…”

“…Additionally, the solubility of an antibiotic can be controlled based on pH [31]. However, as a hydrochloride salt form, it shows slow dissolution in stomach at acidic pH due to common ion effect [31]. Ciprofloxacin shows low solubility at neutral pH, leading to low bioavailability.…”

“…Ciprofloxacin shows low solubility at neutral pH, leading to low bioavailability. Alternatively, the addition of carboxylic acid salts, oxalate, tartarate, benzoate, malonate, and citrate, to nofloxacin or ciprofloxacin showed higher solubility and faster dissolution at pH 6.4 in pure water and at 6.8 in phosphate buffered saline (PBS), though the opposite effect was observed at an acidic pH of 1.2 [31]. Changing the solubility of the parent compound via addition of an organic counter ion can also stabilize the parent compound, as demonstrated by the improved stability of norfloxacin, which is transformed into dihydrate at similar conditions [32].…”

Novel drug–drug cocrystals of carbamazepine with para-aminosalicylic acid: screening, crystal structures and comparative study of carbamazepine cocrystal formation thermodynamics

“…The binding strength of the solvent in the cocrystal solvate and hydrate can be estimated by calculating the vaporization enthalpy (ΔH S ) of the cocrystal-bound solvent using the following relationship: 42,43 ΔH S = (ΔH T desolv ·100/Δm S )·M S (1) where ΔH T desolv is the desolvation enthalpy determined from the DSC data, Δm S is the mass loss percent measured in the TGA experiment, and M s is the solvent molecular weight. The resulting ΔH S values are shown in Table 6.…”