Solubility of Antibiotics in Different Solvents. 1. Hydrochloride Forms of Tetracycline, Moxifloxacin, and Ciprofloxacin

Abstract

The solubilities of tetracycline hydrochloride, moxifloxacin hydrochloride, and ciprofloxacin hydrochloride were measured in several solvents, such as water, ethanol, 2-propanol, and acetone, in the temperature range of 293.15-323.15 K for ciprofloxacin.HCl and moxifloxacin.HCl and 288.15-310.15 K for tetracycline. All the antibiotics have the same solubility order; that is, they are more soluble in water than in ethanol, and more soluble in ethanol than in 2-propanol and acetone. The solubility in water is ∼3 orders of magnitude higher than that in acetone. The modeling of the experimental solid-liquid equilibria (SLE) data, using the NRTL and UNIQUAC models, proves that these models can correlate the solubility of studied antibiotics satisfactorily in the temperature range for which experimental data are available, with the UNIQUAC model generally being slightly superior to the NRTL model, when only two adjustable parameters are used for each binary system.

Optimization of tetracycline hydrochloride adsorption on amino modified SBA-15 using response surface methodology

“…indicated similar results as reported by Turku et al [54]. Further, increasing temperature leads to more drugs in water rather than in porous silica as the solubility of TC increases in water at high temperature [55].…”

Ciprofloxacin: review on developments in synthetic, analytical, and medicinal aspects

“…This depicts that ciprofloxacin has two ionizable functional groups, the 6-carboxylic group and the N-4 of the piperazine substituent. Since carboxylic acid is normally a stronger acid than the ammonium group, the first ionization constant pKa 1 (6.09) corresponds to the dissociation of a proton from the carboxyl group, while pKa 2 (8.62) corresponds to the dissociation of a proton from the N-4 in the piperazinyl group 64,65 . At the most physiologically relevant pH, the pKa 2 value is 8.25, and significant dissociation of both the 6-carboxylic acid and the basic 10-(1-piperazino) groups occurs, leading to significant fractions of zwitterionic species.…”

Solubility of sodium diclofenac in different solvents

“…HCL and ciprofloxacin base in different solvents by Melo et al [9] and Varanda et al [10], using the UNIQUAC and the NRTL model. Variations [11] of UNIQUAC equations have been used to correlate experimental solubility data for polar solid organic solutes in water, e.g.…”