Validated LC-MS/MS Method for Quantifying the Antiparasitic Nitroimidazole DNDI-0690 in Preclinical Target Site PK/PD Studies

Understanding the target site pharmacokinetics (PK) of the nitroimidazole analog DNDI-0690, a potential drug for the neglected parasitic disease leishmaniasis, is important due to the diversity of infected tissue sites and potential drug penetration variability. An ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for quantifying DNDI-0690 in murine biomatrices (plasma, liver, spleen, skin, and skin microdialysate). The method used three protein precipitation sample preparation procedures, tailored for different biomatrices, utilizing a surrogate biomatrix approach. Murine tissues were enzymatically homogenized with a Collagenase A mixture. Chromatographic detection was performed on a C18 column using gradient elution, coupled to a QTRAP6500 quadrupole MS, operating in positive ionization mode. The method demonstrated accurate and precise quantification of all murine biomatrices on the surrogate biomatrix calibration standards, with a high and reproducible total recovery ranging from 75.9% to 94.2% (CV% ≤ 2.5%). Matrix interferences were mitigated with a deuterated internal standard. Stability experiments demonstrated that DNDI-0690 remained stable in all biomatrices under various conditions. This validated UHPLC-MS/MS method was successfully used to quantify DNDI-0690 in a target site murine infection model, demonstrating its suitability for future target site PK studies involving DNDI-0690.