title: Solid-state chemistry of ambroxol theophylline-7-acetate.
abstract: Ambroxol theophylline-7-acetate (ACE) is the salt obtained by reaction of equimolar amounts of ambroxol (AMB), a drug showing mucolytic and expectorant properties, and theophylline-7-acetic acid (TAA), a xanthine derivative with specific bronchodilator activity. ACE is used for the treatment of bronchial and pulmonary diseases (bronchitis, asthma, emphysema, chronic obstructive disease). Recrystallization experiments of ACE resulted in the isolation of two polymorphs (monotropically related) and four solvated forms. X-ray diffractometry, DSC, TGA, and HSM techniques were used to investigate the forms that are obtained by thermal desolvation of the solvates. The phase diagram of the TAA-AMB binary system was constructed by performing thermal analyses on mixtures of TAA-AMB and of each component plus the interaction compound (TAA-ACE and ACE-AMB). The Schroeder-Van Laar equation proved to be a very useful tool for checking the consistency between the experimental data and the theoretical model related to the general system, showing complete miscibility in the liquid phase and complete immiscibility in the solid phase.
authors: Istituto di Chimica Farmaceutica e Tossicologica Pietro Pratesi, University of Milano, 20131 Milano, Italy.
authors: Anastasia
authors: A
authors: Foppoli
authors: Lucia
authors: L
authors: Zema
authors: Andrea
authors: A
authors: Gazzaniga
authors: Mino R
authors: MR
authors: Caira
authors: Luigi R
authors: LR
authors: Nassimbeni
authors: Evan
authors: E
authors: Borkum
authors: Ruggero
authors: R
authors: Bettini
authors: Ferdinando
authors: F
authors: Giordano
mesh_terms: D000551:Ambroxol / Q000031:analogs & derivatives* / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D002626:Chemistry, Pharmaceutical; D003460:Crystallization; D018360:Crystallography, X-Ray; D008859:Microscopy, Polarization; D008956:Models, Chemical; D044367:Phase Transition; D015203:Reproducibility of Results; D019141:Respiratory System Agents / Q000737:chemistry*; D012995:Solubility; D012997:Solvents / Q000737:chemistry*; D013696:Temperature; D013806:Theophylline / Q000031:analogs & derivatives* / Q000737:chemistry; D013816:Thermodynamics; D013818:Thermogravimetry
chemical_list: D019141:Respiratory System Agents; D012997:Solvents; C077110:ambroxol-theophylline-7-acetate; D000551:Ambroxol; D013806:Theophylline