Inductively coupled plasma mass spectrometry method for plasma and intracellular antimony quantification applied to pharmacokinetics of meglumine antimoniate

BACKGROUND: A high-throughput method using inductively coupled plasma mass spectrometry (ICP–MS) was developed and validated for the quantitative analysis of antimony in human plasma and peripheral blood mononuclear cells from patients with cutaneous leishmaniasis undergoing treatment with meglumine antimoniate. MATERIALS & METHODS: Antimony was digested in clinical samples with 1% tetramethylammonium hydroxide/1% EDTA and indium was used as internal standard. Accuracy, precision and stability were evaluated. CONCLUSION: Taking the lower limit of quantitation to be the lowest validation concentration with precision and accuracy within 20%, the current assay was successfully validated from 25 to 10000 ng/ml for antimony in human plasma and peripheral blood mononuclear cells. This protocol will serve as a baseline for future analytical designs, aiming to provide a reference method to allow inter-study comparisons. LAY ABSTRACT: Cutaneous leishmaniasis is a disease caused by single-cell parasites in the genus Leishmania which results in painful skin ulcers and is spread by insect bites. Drugs containing antimony are the mainstay therapy for cutaneous leishmaniasis, but if and how the amount of these compounds in the cells can affect the success of the treatment, remains unknown. Validated methods to reliably measure these amounts in human cells are limited. Here we have developed a validated method that allows quantifying antimony in human plasma and peripheral blood cells from patients undergoing antileishmanial treatment. This protocol will serve as a baseline for future studies aiming to understand how antimonials work to treat leishmaniasis infections and how this therapy can be improved.