Aspectos termodinámicos de la miscibilidad parcial entre el n-octanol y el agua

Thermodynamics of partitioning and solvation of ketoprofen in some organic solvent: buffer and liposome systems

“…When comparing the results obtained for all organic solvents, it can be deduced a higher preference of KTP for octanol, respect to the other tested solvents, in particular regarding cyclohexane. As has been previously described in literature (Sangster, 1997;Mora et al, 2005), ROH has a microheterogeneus structure on water saturation. For this reason, ROH interacts with KTP by hydrogen bonding thorough carbonyl and carboxyl groups present in this drug, in addition to weak interactions, such as London dispersion forces, which conduce to structural immobilization of drug molecules near to the alkyl moieties of octanol.…”

“…These values could be explained in terms of a possible organization in the water-saturated octanol due to the replacement of an octanol molecule by one of drug. This replacement would be present in some of centers conformed by two water molecules and four octanol molecules, inside the microheterogeneus structure of this water-saturated organic solvent (Sangster, 1997;Mora et al, 2005). The previous event releases energy and compensates the molecular disorder produced by the drugorganic solvent mixing process.…”

“…Samples were placed on water baths (Magni Whirl Blue M. Electric Company, USA) at 20.0, 25.0, 30.0, 35.0, 40.0, and 45.0 °C (± 0.1 °C) at least for 48 hours with sporadic stirring in order to achieve the partitioning equilibrium, as it was made studying other compounds (Martínez, Gómez, 2002). After this time-period, the aqueous phase was removed followed by determining the drug concentration by means of UV absorbance measurement and interpolation on a previously constructed calibration curve for KTP in a buffer pH 7.4 (Unicam UV2-100 spectrophotometer, USA for CHL-saturated buffer (Dallos, Liszi, 1995;Baena et al, 2005;Mora et al, 2005).…”

“…CH is an aprotic solvent unable to form hydrogen bonds as donor or acceptor, and therefore acts only through non-specific interactions (London forces). However hydroxyl group of ROH can be an acceptor and/or a donor of protons, and moreover, as was already expressed, its alkyl moieties allow the structural immobilization of solutes due to the tetrahedral microstructure adopted in saturation by this solvent in contrast to the CH behavior (Sangster, 1997;Mora et al, 2005 ). The acid hydrogen present in this drug is the one present in its carboxylic group.…”

Thermodynamic quantities of solvation and dilution for some acetanilide derivatives in octanol and water mutually saturateds

“…These values could be explained in terms of a possible organization in the water-saturated octanol due to the replacement of an octanol molecule by a drug molecule. This replacement would be present in some centers conformed by two water molecules and six octanol molecules, inside the microheterogeneus structure of this water-saturated organic solvent [4,13]. The previous event releases energy and compensates the molecular disorder produced by the drug-organic solvent mixing process and the energy intake required in the aqueous media to separate the water molecules present around the non polar groups of this drug.…”