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Thermodynamic study of the solubility of acetaminophen in propylene glycol + water cosolvent mixtures

“…In a first approach the term( V 2 φ 1 2 / RT) may be considered approximately constant at the same temperature, and then γ 2 depends almost exclusively on w 11, w 22 and w 12 . 21 The w 11 and w 22 terms are unfavorable for solubility, while the w 12 term favors the solution process.…”

“…The solution process may be represented by the following hypothetic stages: 21 Solute (Solid) → Solute (Liquid) → Solute (Solution) where, fusion and mixing are the respective partial processes toward the solution process at 303 K. This approximation permits to calculate the partial thermodynamic contributions to solution process by means of equations (15) and (16). Table 5 the thermodynamic functions of mixing of ACP are summarized.…”

Thermodynamic study of the solubility of some sulfonamides in cyclohexane

“…These values are lower than those obtained in other solvents used in QSAR studies, such as water or octanol. 5,7 The experimental solubility decreases in the order SMT > SMX > SP > SMR > SCM > SA > STL > SD, which is different than that for the ideal solubility. The sequence for the experimental solubilities is almost the same of partial molar volumes at infinite dilution in the (x = 0.5) water-ethanol mixture (the volume decreases in the order SMT > SMX > SP > SA > SMR > SD > SCM > STL).…”

“…2 Mauger et al 3 have determined the solubility of sulfadiazine, sulfisomidine, sulfadimethoxine, and sulfisoxazole in some alcohols at 25, 30, and 37 °C, while Regosz et al, 4 have evaluated the aqueous solubility of a variety of sulfonamides at several temperatures. Martínez and Gómez 5 have studied the thermodynamics of solution of some sulfonamides in octanol, water, and the mutually saturated solvents. In order to have systematic and more complete physicochemical information about the transfer of sulfonamides between aqueous and organic phases, in this work the solubility of eight structurally related sulfonamides in cyclohexane was determined at several temperatures, and the related thermodynamic functions were calculated.…”

“…14, No. 5,2003 Since ∆C p cannot be easy experimentally determined, one of the following assumptions has to be made: (a) ∆C p is negligible and can be considered zero or (b) ∆C p may be approximated to the entropy of fusion, ∆ fus S. The simplified equation is: 12 There are only a few values of enthalpy and entropy of fusion reported in the literature, and they have been obtained by differential thermal analysis (DTA), a semiquantitative method, while the values presented here were obtained by DSC, a quantitative method, the latter being more appropriate for the determination of molar enthalpies of fusion. Our values are generally greater than those reported by Yang and Guillory, 13 and Sunwoo and Eisen, 14 but for SD and SMR, they are very similar to those reported by Maury et al 15 Since the ideal solubility depends on the melting point and the enthalpy of fusion, it is important to know how these properties vary among the various sulfonamides.…”