Remarks on “measurement and correlation of solubility of tetracycline hydrochloride in six organic solvents”

Errors were discovered concerning the published equation coefficients of Zhao and co-workers [J. Chem. Thermodyn. 57 (2013) 9–13] for mathematically describing the solubility of tetracycline hydrochloride (TCH) in methanol, ethanol, 1-propanol, 1-butanol, acetone and acetonitrile by using the NRTL model. The curve-fit coefficients fail to describe the reported solubility data in the authors' published paper. The equation parameters were re-analyzed based on the reported solubility data.