Pharmacokinetics and Tissue Distribution of Antimony(v) after Multiple Intramuscular Administrations in the Hamster

The fate of pentavalent antimony (Sb^v) in different tissues in the body after intramuscularadministration is of great interest for the future study of Sb v therapy in different sitting.Pharmacokinetics and tissue distribution of antimony (Sb^v) were studied in the hamster after dailydose of sodium stibogluconate equivalent to 120 mg kg-lof Sb v, administered intramuscularly fortwo weeks. Liver, spleen, heart, kidney and skin tissues were isolated after blood collection at thespecified time. Antimony was measured in these tissues after suitable treatment, ashing andprocessing, by flameless atomic absorption spectrophotometry. The concentrations of Sb^v timeprofile in blood showed a linear rapid decline with elimination half life (t1/2) of 1.7 h. The concentration of drug (mu g/gm) declined in a biphasic manner from almost all tissues. However, the concentrations of Sb v were declined in slower fashion from the hamster tissues than from the blood. The maximum concentration of Sb v was determined in the kidney tissues (3416 ± 631 mug/gm) while the lowest concentration was in the spleen (209 ± 187 mu g/gm). The maximum concentration of Sb^v in the kidney (mu g/gm) was more than 25 fold higher than that measured from blood (mu g/ml). The AUC of Sb v in the studied tissues was in this rank: kidney liver skin spleen heart blood. Surprisingly, the heart, spleen and liver showed a similar t1/2 of 5.2-6.2 h while the kidney and skin had a t1/2 of about 3 h. Therefore, disposition of Sb^ v seems to kinetically follow multicompartmental compartmental model. The kidneys got the highest concentration of drug which may lead to nephrotoxicity on long term therapy.