Atefeh Sheikhi-Sovari; Mohammad Barzegar-Jalali; Fleming Martinez; Behrouz Seyfinejad; Elaheh Rahimpour; Abolghasem Jouyban

In this study, the solubility of clonazepam (CZP) in binary solvent mixtures of (1-propanol + water) and (2-propanol + water) at five different temperatures was investigated. The solubility of CZP was assessed using the shake-flask technique, while the concentrations of CZP in the solutions were measured utilizing a UV-Vis spectrophotometer. The obtained solubility data were analyzed using the main mathematical models available in this context. The experimental data obtained for CZP dissolution encompassed various thermodynamic properties, including ΔG°, ΔH°, TΔS°, and ΔS°. These properties offer valuable insights into the energetic aspects of the dissolution process. The results revealed that the solubility of CZP in both binary solvent mixtures increased with increasing alcohol concentration and temperature. The mathematical models provided accurate predictions of the solubility of CZP in these binary solvent systems (MRDs% were less than 14.3). Based on the thermodynamic analysis, it was determined that the dissolution of CZP in the examined mixtures is endothermic. Furthermore, the inverse Kirkwood-Buff integrals revealed the presence of preferential hydration of CZP in mixtures that were rich in water as well as those rich in cosolvent.