Solubility and thermodynamic analysis of N′-(1-(N-(methyl) benzylaminomethyl)-2-oxoindolin-3-ylidene)-2-(benzyloxy) benzohydrazide in different neat solvents at different temperatures

The present study was undertaken to determine the solubilities of newly synthesized anticancer compound N′-(1-(N-(methyl) benzylaminomethyl)-2-oxoindolin-3-ylidene)-2-(benzyloxy) benzohydrazide (NMBOBB) in nine different neat solvents including water, isopropanol (IPA), ethanol, ethylene glycol (EG), 1.2-propanediol (PG), 1-butanol, 2-butanol, polyethylene glycol-400 (PEG-400) and Transcutol (diethylene glycol monoethyl ether) at T = 298.15 K to 318.15 K and p = 0.1 MPa. Experimental solubility data of NMBOBB was fitted with Apelblat and ideal models. The mole fraction solubility of NMBOBB was recorded highest in PEG-400 (1.14 × 10− 2 at T = 318.15 K) followed by Transcutol (7.14 × 10− 3 at T = 318.15 K), 2-butanol (1.45 × 10− 3 at T = 318.15 K), 1-butanol (1.38 × 10− 3 at T = 318.15 K), ethanol (9.69 × 10− 4 at T = 318.15 K), PG (9.52 × 10− 4 at T = 318.15 K), IPA (9.41 × 10− 4 at T = 318.15 K), EG (8.09 × 10− 4 at T = 318.15 K) and water (3.00 × 10− 6 at T = 318.15 K). The highest solubility of NMBOBB in PEG-400 was possible due to lower polarity and higher molar mass of PEG-400. The dissolution behavior of NMBOBB was observed as an endothermic, spontaneous and an entropy-driven due to positive values of standard enthalpies, Gibbs free energies and entropies in all nine neat solvents investigated. The results of this work would be helpful in purification, recrystallization and dosage form design of NMBOBB.