Determination of antimony in biological materials by electrothermal atomic absorption spectroscopy.

An electrothermal atomic absorption method for the determination of antimony in biological fluids, derived from Triostam or Pentostam, is described. Comparison of the results obtained by this method has been made with hydride generation atomic absorption and by measuring the gamma emission of 125Sb-Pentostam. Using electrothermal atomic absorption, the concentrations and distributions of the pentavalent and trivalent antimony drugs, either in free or liposome-entrapped forms, have been determined in vitro after incubation with human blood. The effect of entrapping Pentostam within liposomes has also been studied in vivo in mice, and its concentration and distribution compared with results obtained using the free drug.