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Chemical methods specific for the determination of the levels of trivalent antimony (Sb+3) and pentavalent antimony (Sb+5) were used to investigate proprietary formulas used to treat leishmaniasis. Trivalent antimony was determined by differential pulse polarography, whereas Sb+5 was determined by iodine titration. Proprietary formulas based on N-meglumine antimoniate (Glucantime) were analyzed in detail. The results showed Sb+3 in all ampules of Glucantime. In formulations said to contain either 85 or 100 mg of Sb+5/ml, we found both forms of antimony. The amount of Sb+3 ranged from 10.5 to 15.8% (10.06-18.96 mg of Sb/ml). These findings raise issues on product stability and standardization and may help to clarify resistance to antimonial drugs and the reducing effect of tissue on Sb+5.

Leishmaniasis patients were treated with N-methylglucamine antimoniate by intravenous injections of 10 or 20 mg of Sb per kilogram of body weight per day for 10 or 20 days. Digests of skin biopsies taken from the site of lesion before and after treatment were analyzed for antimony by instrumental neutron activation (INAA). The detection limit of the assay was 20 ng, and no Sb could be measured in digests of samples (less than 2.45 mg) taken before treatment. Biopsies taken after injections of Sb showed concentrations in the range of 8.32 to 70.68 ng/g skin. We discuss the usefulness of INAA in the study of Sb in small samples of tissues.

We used instrumental neutron activation analysis (INAA) to determine antimony in small quantities of hair from individuals living in an area of endemic leishmaniasis. The groups studied were 12 patients undergoing treatment with N-methylglucamine antimoniate, 34 patients who had received such treatment a year ago, and 17 control subjects (untreated) who were living in the same area. Patients receiving treatment showed mean and median (12.13, 2.9 micrograms/g) values for antimony in hair that significantly exceeded those in either controls (1.01, 0.4 microgram/g) or patients one year after treatment (1.54, 1.0 microgram/g). We conclude that INAA can be useful in monitoring and differentiating such exposure to antimony in patients under treatment.