Disposition of antimony and aminosidine combination after multiple subcutaneous injections in dogs

The disposition of a combination of antimony (Sb(v)) (12.8 mg/kg) and aminosidine (AM) (10 mg/kg) in 10 healthy Beagle dogs after multiple subcutaneous injections is described. Sb(v) plasma concentrations were determined by atomic absorption spectrometry, and AM by ion-pair liquid chromatography, using a fluorimetric detector Sb(v) reached C(max) at 60 min, and for about 1 h plasma levels were homogeneously stabilized between 10.78 and 11.76 μg/mL; by 12 h, Sb(v) plasma concentrations were close to the detection limit (0.3 μg/mL). AM C(max) values were recorded after 1 h (30.6 ± 3.11 μg/mL, mean ± SD), and plasma levels reached values close to the detection limit (0.15 μg/mL) between 7 and 8 h after injection. Sb(v) kinetic parameters did not appear modified by the presence of AM. Moreover, repeated injections of the combination did not modify the kinetic behaviour of the two drugs and did not alter the renal function of the animals. The superimposition analysis of the Sb(v) data suggests that a twice daily injection of the metal at a dose of 12.8 mg/kg would be sufficient to maintain inhibitory Sb(v) concentrations similar to those recorded in humans.