Abstract
The solubility of N-(4-chlorophenyl)-2-(pyridin-4-ylcarbonyl)-hydrazinecarbothioamide (isoniazid analogue) in various diethylene glycol monoethyl ether (Transcutol) + water cosolvent mixtures was measured at (298.15 to 338.15) K using the shake flask method. In order to investigate the influence of temperature on solubility, the experimental solubilities of the isoniazid analogue were correlated with the Apelblat equation. To investigate the influence of cosolvent mixtures on solubility, the log-linear model of Yalkowsky was used. For the Apelblat equation, the root-mean-square deviations (RMSDs) were observed in the range of 0.004 to 0.033. For the Yalkowsky model, the RMSDs were observed in the range of 0.021 to 0.114. The correlation coefficients were observed in the range of 0.996 to 0.999. These results indicated the good fitting of experimental solubilities with the Apelblat equation and Yalkowsky model. The solubility of isoniazid analogue was found to be highest and lowest in pure Transcutol (4.23.10(-2) at 298.15 K) and pure water (5.17.10(-7) at 298.15 K), respectively. Thermo-dynamic parameters such as molar enthalpies and entropies were observed as P I positive values in all cosolvent mixtures, indicating that the dissolution process for the isoniazid analogue is endothermic and entropy-driven. Based on the solubility data of the current study, the isoniazid analogue has been considered as freely soluble in Transcutol and practically insoluble in water.