Determination of streptomycin and doxycycline using LC/MS towards an effective treatment against an experimental Brucella abortus infection in mice.

Herein we described a versatile liquid chromatographic method for detection and quantification of the total levels of two antimicrobials [i.e., streptomycin (STM) and doxycycline (DOX)], in mice plasma and selected tissues, with the aid of a single quadrupole as a detection method. The method included a few sample preparation steps, including freeze-drying and in situ triphasic solvent-assisted defatting, precipitation, and extraction, allowing easy and fast tissue sample processing and avoiding analyte loss. Using a murine model, we demonstrated that mass spectrometry detects simultaneously and with high specificity two of the most widespread antimicrobials used against Brucellosis. An accurate [recoveries varied from 75.23 (bone marrow) to 101.33% (liver)] and sensitive (LoD in the ng g range) method to assess STM and DOX in murine tissue, including subtherapeutic and therapeutic doses of the antimicrobials, was achieved. This validated method can be successfully used to monitor the depletion of STM and DOX in several mice tissues and plasma during metabolism after administration.