A simple LC–MS/MS method for determination of sitafloxacin in human urine

• To develop and validate an LC–MS/MS method for quantification of sitafloxacin in human urine, and show its application in a clinical study.
• Simple sample preparation provided high efficiency in analyzing high-throughput samples.
• The developed LC–MS/MS method has been validated and shows excellent performance.
• The method can be used for clinical urine recovery study.
• Approximately 65% of the unchanged drug of sitafloxacin was secreted in this urine recovery study.

Sitafloxacin is a new fluoroquinolone antimicrobial agent with high activity. In this article, we reported a simple, rapid and specific LC–MS/MS method for accurate determination of sitafloxacin concentrations in human urine from healthy volunteers in detail. A two-step dilution method for the analysis of sitafloxacin in human urine using LC coupled to positive MS/MS has been developed and validated according to US FDA guidelines and Chinese State Food and Drug Administration (CFDA) guidelines for the validation of bioanalytical methods. The method uses 50 μL of urine and covers a working range from 0.025 to 20 μg/mL with a LLOQ of 0.025 μg/mL. This new LC–MS/MS assay is sensitive and specific.