title: Reaction of sodium amoxicillin with Cu(II) ion in a methanolic medium.
abstract: The present article considers several physicochemical aspects of the complexation reaction of sodium amoxicillin and Cu(II) ion in a methanolic medium. Analysis of spectrophotometric data demonstrated the formation of two complex species with amoxicillin:Cu(II) ion mole ratios of 1:1 and 2:1. Stability constants (beta) and molar absorptivities at 610 nm (epsilon) of the complexes (20 degrees C) in methanol were calculated simultaneously by a computer program on the basis of absorbance data obtained at 610 nm. The values thus calculated for the 1:1 complex were as follows: log beta 1 = 5.48 +/- 0.21 L.mol-1, epsilon 1 = 70 +/- 2 L.mol-1.cm-1. The values for the 2:1 complex were as follows: log beta 2 = 8.98 +/- 0.17 L2.mol-2 and epsilon 2 = 138 +/- 4 L.mol-1.cm-1. The amoxicillin:Cu(II) ion complexes were quite stable over time.
authors.affiliation: Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Gutiérrez Navarro
authors.forename: P J
authors.initials: PJ
authors.lastname: Martínez de las Parras
authors.forename: A
authors.initials: A
authors.lastname: Marquez Garcia
mesh_terms: D000658:Amoxicillin / Q000737:chemistry*; D003300:Copper; D004355:Drug Stability; D000432:Methanol; D013053:Spectrophotometry
chemical_list: D003300:Copper; D000658:Amoxicillin; D000432:Methanol