Colloid and Polymer Science

, Volume 280, Issue 7, pp 624–629

A thermodynamic study of the aggregation process of oxacillin sodium salt in aqueous solution

  • Laura Seoane
  • Pablo Martínez-Landeira
  • Lina Besada
  • Juan M. Ruso
  • Félix Sarmiento
  • Gerardo Prieto
Contribution

DOI: 10.1007/s00396-002-0657-4

Cite this article as:
Seoane, L., Martínez-Landeira, P., Besada, L. et al. Colloid Polym Sci (2002) 280: 624. doi:10.1007/s00396-002-0657-4

Abstract.

The aggregation characteristics of oxacillin in aqueous solutions have been examined by means of conductivity measurements over the temperature range 288.15–313.15 K and by static light scattering measurements at 298.15 K. Two critical concentrations were detected in conductivity and light scattering over the concentration range 0–0.35 mol kg–1. Light scattering measurements indicate the formation of dimers at the first critical concentration (0.024 mol kg–1) and the subsequent formation of aggregates with an aggregation number of 8 at the second critical concentration (0.104 molkg–1). The thermodynamic parameters of aggregation were derived from the critical concentration data using a mass-action model that has been modified for application to systems of low aggregation number. Values for the enthalpy of aggregate formation calculated by this method showed that the aggregation became increasingly exothermic with increasing temperature. The values of the two critical concentrations show that this penicillin, oxacillin, is more hydrophobic than other molecules of similar structure.

Aggregation Oxacillin Critical micelle concentration Thermodynamics Conductivity Light scattering 

Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  • Laura Seoane
    • 1
  • Pablo Martínez-Landeira
    • 1
  • Lina Besada
    • 1
  • Juan M. Ruso
    • 1
  • Félix Sarmiento
    • 1
  • Gerardo Prieto
    • 1
  1. 1.Grupo de Biofísica e Interfases, Departamento de Física Aplicada, Facultade de Física, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain

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