title: Isoxazoles. 8. Preformulation studies of an isoxazolylnaphthoquinone derivative.
abstract: The degradation kinetics of 2-hydroxy-N-(3,4-dimethyl-5-isoxazolyl)-1,4-naphthoquinone 4-imine (1) in a 25% solution of ethyl alcohol in water has been studied. The rate constants were observed to follow pseudo-first-order kinetics in all cases. The pH-rate profile indicated a negligible decomposition at pH values higher than its pKa2 value [5.4 +/- 0.14 (*n = 6)]. Un-ionized 1 was subject to specific acid catalysis. The ionic strength did not affect the stability of the drug. These data can be used to develop a stable oral liquid dosage form of the drug.
authors.affiliation: Departmento de Farmacia, Facultad de Ciencias Quimicas, Universidad Nacional de Córdoba, Argentina.
authors.forename: M R
authors.initials: MR
authors.lastname: Longhi
authors.forename: M M
authors.initials: MM
authors.lastname: de Bertorello
authors.forename: G E
authors.initials: GE
authors.lastname: Granero
mesh_terms: D004355:Drug Stability; D006863:Hydrogen-Ion Concentration; D007555:Isoxazoles / Q000737:chemistry* / Q000493:pharmacokinetics; D009285:Naphthoquinones / Q000737:chemistry* / Q000493:pharmacokinetics; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D014344:Trypanocidal Agents / Q000737:chemistry* / Q000493:pharmacokinetics
chemical_list: D007555:Isoxazoles; D009285:Naphthoquinones; D014344:Trypanocidal Agents