Research on Dissolution Capability of Several Antofloxacin Salts

Abstract

The solubilities of three antofloxacin salts (antofloxacin hydrochloride, antofloxacin sulfate, and antofloxacin succinate) in six organic solvents, including methanol, ethanol, n-propanol, n-butanol, acetonitrile, and N,N-dimethylformamide (DMF), were determined experimentally over a temperature range from 273.15 to 318.15 K under 101.3 kPa. Within the temperature range studied, the solubility of these three compounds in the solvents increased with a rise of temperature. The solubility values of antofloxacin hydrochloride in these six solvents obey the following order: (methanol, DMF) > n-butanol > ethanol > n-propanol > acetonitrile. For the systems of antofloxacin sulfate + solvents, it ranked as DMF > methanol > ethanol > acetonitrile > n-propanol > n-butanol. While for antofloxacin succinate + solvents, the order of the data from high to low is DMF > methanol > n-butanol > n-propanol > ethanol > acetonitrile. The solubility data obtained for these three compounds in the studied solvents were correlated by using the modified Apelblat and λh equations. The maximum values of root-mean-square deviation (RMSD) and relative average deviation (RAD) were 3.3 × 10 −5 and 4.06%, respectively. Generally, the RAD values acquired with the modified Apelblat equation were smaller than λh equation for a certain solvent. The two thermodynamic models were all acceptable for the systems of these three compounds in these solvents. The obtained solubility values would be very helpful for drug application of antofloxacin hydrochloride, antofloxacin sulfate, and antofloxacin succinate.

Solid–Liquid Equilibrium Measurements for Posaconazole and Voriconazole in Several Solvents between T = 278.2 and 323.2 K Using Differential Thermal Analysis/Thermal Gravimetric Analysis

“…The modified Apelblat equation is often preferred for the direct empirical correlation of T – x solid–liquid equilibrium data in place of eq , which employs correlation via activity coefficients. This is because it has provided excellent fitting results for numerous solution systems in low solubility ranges as shown in recent studies. − It is useful for the correlation of SLE data as precise interpolation to different solubility temperatures can be easily achieved within the experimental range.…”

“…The equilibration measurement procedure has been applied before in the literature − and has been verified in previous works. − To confirm the procedures used for the binary solubility data, a test measurement for the benzoic acid (1) + water (2) system was conducted and compared to literature data. This is shown in Figure .…”

Solubility Increment and Thermodynamic Analysis of Bioactive Antofloxacin Hydrochloride in Aqueous ChCl/PTS Deep Eutectic Solvent and Cosolvent Mixtures

“…Experimental equilibrium solubility ( x , in mole fraction) of antofloxacin hydrochloride in (ethanol, w + acetonitrile, 1 – w ) system at 273.15–318.15 K: ☆, w = 0; △, w = 0.1; ★, w = 0.2; ◇, w = 0.3; ▶, w = 0.4; ×, w = 0.5; ●, w = 0.6;▼, w = 0.7;▲, w = 0.8; ◆, w = 0.9; ■, w = 1; , calculated data via modified Apelblat equation.…”

“… a Taken from ref . b Calculated using Advanced Chemistry Development (ACD/Labs) Software V11.02 (©1994-2019 ACD/Labs). c,d Taken from refs and , respectively. e High-performance liquid phase chromatography. fT he purity was provided by supplier. …”

“…The melting temperatures T m of antofloxacin hydrochloride, p -toluenesulfonic acid monohydrate, and choline chloride were provided by the refs , . Further, the densities of the above solvents were referred to the publication …”