Speciation of Antimony in Injectable Leishmanicidal Drugs by Lowering Citric Acid Concentration Used in Hydride Generation Atomic Absorption Spectrometry Analysis

This study proposes a procedure for speciation of antimony by hydride generation atomic absorption spectrometry in pentavalent antimony drugs. The SbIII content was determined by selective generation of SbH3 in medium with higher SbV concentration using 4 to 20-fold lower citric acid solutions than recommended in the available literature. The multivariate optimization of the methods was performed through factorial design followed by a central composite design (CCD). The limit of detection (LOD) and limit of quantification (LOQ) were calculated at 0.15 and 0.05 µg L-1 and 0.48 and 0.17 µg L-1, for total Sb and SbIII, respectively. The relative standard deviation (RSD) values ranged from 3.1 to 19.6% and 9.1 to 20.1%, while recovery ranged from 95.6 to 102.3% and 89.1 to 108.1%, for total Sb and SbIII, respectively. This method was applied for the analysis of meglumine antimoniate samples. Total Sb and SbIII concentrations ranged from 79.2 to 101.1 mg mL-1 and 0.08 to 0.41 mg mL-1, respectively.