Introduction: Oxacillin sodium is a semisynthetic penicillin used in therapy against Staphylococcus species. It is orally administered as capsules. Because of the low stability of oxacillin in stomach acid, a low bioavailability is recorded during oral administration (30%).
The aim of this study was to improve, by using some auxiliary substances, the stability of oxacillin in acidic environment.
Methods: The improvement of oxacillin stability was measured by high performance liquid chromatography in the presence of β-cyclodextrin, 2-HP-β-cyclodextrin, magnesium glutamate and magnesium aspartate.
Results: Cyclodextrins significantly improved the stability of oxacillin in acidic environment. Glutamate and aspartate showed no effect on this regard. First order decomposition kinetics of oxacillin was modified by cyclodextrins.
Conclusions: Significant improvement of oxacillin stability and possible pharmacokinetics can be achieved by using cyclodextrins.