title: Thermodynamics of dissolution and infrared-spectroscopy of solid dispersions of phenacetin.
abstract: In this work enthalpies of dissolution in water of polyethylene glycols (PEGs) having an average molecular weight of 1000 and 1400, Pluronic-F127, phenacetin as well as the composites prepared from them were measured using solution calorimetry at 298.15 K. Intermolecular interaction energies of polymer-phenacetin were calculated on the basis of an additive scheme. It was shown that for mixtures with high content of polymer (>90 wt%) Pluronic-F127 has the highest solubilizing effect, while for mixtures with (4-6):1 polymer: phenacetin ratio the best solubilizing agent is PEG-1400. Infrared-spectra showed a decrease of the number of self-associated molecules of phenacetin with increasing of polymer content in the composites. The obtained results enabled us to identify the features of intermolecular interactions of polymers with a model hydrophobic drug and may be used for optimizing the conditions for preparing solid dispersions based on hydrophilic polymers.
authors.affiliation: Department of Physical Chemistry, Butlerov Institute of Chemistry, Kazan Federal University, Kremlevskaya 18, Kazan 420008, Russia.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Gerasimov
authors.affiliation: Department of Physical Chemistry, Butlerov Institute of Chemistry, Kazan Federal University, Kremlevskaya 18, Kazan 420008, Russia.
authors.forename: Mikhail A
authors.initials: MA
authors.lastname: Varfolomeev
authors.affiliation: Department of Physical Chemistry, Butlerov Institute of Chemistry, Kazan Federal University, Kremlevskaya 18, Kazan 420008, Russia.
authors.forename: Marat A
authors.initials: MA
authors.lastname: Ziganshin
authors.affiliation: Department of Physical Chemistry, Butlerov Institute of Chemistry, Kazan Federal University, Kremlevskaya 18, Kazan 420008, Russia.
authors.forename: Valery V
authors.initials: VV
authors.lastname: Gorbatchuk
authors.affiliation: Department of Physical Chemistry, Butlerov Institute of Chemistry, Kazan Federal University, Kremlevskaya 18, Kazan 420008, Russia.
authors.forename: Il'naz T
authors.initials: IT
authors.lastname: Rakipov
authors.affiliation: Department of Physical Chemistry, Butlerov Institute of Chemistry, Kazan Federal University, Kremlevskaya 18, Kazan 420008, Russia.
authors.forename: Alexander E
authors.initials: AE
authors.lastname: Klimovitskii
authors.affiliation: Department of Physical Chemistry, Butlerov Institute of Chemistry, Kazan Federal University, Kremlevskaya 18, Kazan 420008, Russia.
authors.forename: Liana S
authors.initials: LS
authors.lastname: Usmanova
keywords: Enthalpy of solution; Pluronic-F127; molecular interaction; phenacetin; polyethylene glycol; solution calorimetry