Quantitative analysis of DNDI-6174 using UPLC-MS/MS: A preclinical target site pharmacokinetic study

Leishmaniasis is a neglected parasitic infection that continues to pose a significant global health challenge, with currently limited effective treatment options. DNDI-6174 is a novel orally-active, investigational drug with antileishmanial properties. Herein, a novel ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) method was developed and validated to quantify DNDI-6174 in relevant murine biomatrices, i.e., K₂EDTA plasma and enzymatically-homogenized skin, spleen and liver to support the translational pharmacokinetic-pharmacodynamic model-informed drug development. The chromatographic system consisted of a gradient elution on a standard C₁₈ column connected to a triple quadrupole MS, operating in positive ionization mode. Pre-processing of murine tissues with collagenase A led to a superior homogenization and analyte extraction compared to mechanical disruption. Human K₂EDTA plasma served as a surrogate matrix, enabling accurate (bias between -12.0 % and 9.8 %) and precise (relative standard deviation (RSD) ≤ 12.5 %) quantification of DNDI-6174 in the various murine biomatrices. Sample processing with tert-methylbutyl ether resulted in a reproducible recovery between 70.0 % and 93.8 % (RSD ≤ 4.0 %) with an absolute matrix factor between 0.89 and 1.00 for all biomatrices. DNDI-6174 was stable under various conditions, including under tissue homogenization conditions, in all biomatrices investigated. This method was successfully applied in a translational study using a murine cutaneous leishmaniasis skin infection model to assess the target site pharmacokinetics of DNDI-6174, supporting its development as clinical candidate.