Thermodynamic study of the solubility of triclocarban in ethanol + propylene glycol mixtures

Abstract

Recebido em 19/1/11; aceito em 1/8/11; publicado na web em 26/9/11 By using the van't Hoff and Gibbs equations the apparent thermodynamic functions Gibbs energy, enthalpy, and entropy of solution for triclocarban in ethanol + propylene glycol mixtures were evaluated from solubility data determined at temperatures from (293.15 to 313.15) K. The drug solubility was greatest in the mixture with 0.60 in mass fraction of ethanol and lowest in neat propylene glycol at almost all the temperatures studied. Non-linear enthalpy-entropy compensation is found indicating apparently different mechanisms of the solution process according to the mixtures composition.

Solution thermodynamics of methocarbamol in some ethanol + water mixtures

“…In contrast to Gibbs energy of solution, D soln H° and D soln S° values decrease from neat water to the mixtures of 0.70 and 0.60 in mass fraction of ethanol, respectively, then increase beyond this mixture composition. These results are similar to those reported for the antimicrobial drug triclocarban in ethanol + propylene glycol mixtures; 17 although it is clear that both drugs have different molecular structures (MTC being more polar than triclocarban owing to its higher number of polar groups) whereas water and propylene glycol exhibit different behaviors in their mixtures with ethanol. Moreover, the effect of cosolvents on possible mixed solvent-structural effects should also be considered.…”

“…The compensation behavior obtained for MTC differs with respect to that reported for all the analgesic drugs studied previously, where entropy driving was observed in water-rich mixtures and enthalpy driving in ethanol-rich mixtures. 5 On the other hand, Figure 5 shows a similar trend to the one reported for triclocarban in ethanol + propylene glycol mixtures, 17 as previously outlined for the respective thermodynamic quantities of solution.…”

Solution thermodynamics and preferential solvation of 3-chloro-N-phenyl-phthalimide in acetone + methanol mixtures

“…Where ∆ soln F° represents the thermodynamic functions (∆ soln G°, ∆ soln H° or ∆ soln S°). This procedure is the same followed previously in other studies reported by Holguín et al and Delgado et al [28][29]. The regions where (Δ tr H° > TΔ tr S °> 0)  sector I; (Δ tr H° <0; T tr ΔS° > 0; |Δ tr H°| > |T tr ΔS°|)  sector IV and (Δ tr H° < 0; TΔ tr S° < 0; |Δ tr H°| > |TΔ tr S°|)  sector V corresponds to enthalpy determined processes.…”

Antibacterial, antifungal, and antiviral activities of chalcone-bearing tetrahydropyranyl and 2,4-dihydroxyl moieties

“…The solute behavior in the dissolution process can generally be divided into two stages, the solute fusion and its subsequent mixing with the solvent, so this hypothetical process can be represented according to the following scheme [29,30]:…”