Simultaneous UHPLC-UV analysis of hydroxychloroquine, minocycline and doxycycline from serum samples for the therapeutic drug monitoring of Q fever and Whipple's disease

A fast UHPLC-UV method was developed for the simultaneous analysis of Hydroxychloroquine, Minocycline and Doxycycline drugs from 100 μL of human serum samples. Serum samples were extracted by liquid-liquid extraction and injected into a phenyl hexyl reverse phase column. Compounds were separated using a mobile phase linear gradient and monitored by UV detection at 343 nm. Chloroquine and Oxytetracycline were used as internal standards. Lower and upper limits of quantifications, as well as the other levels of calibration, were validated with acceptable accuracy (<15% deviation) and precision (<15% coefficient of variation) according to the European Medicines Agency guidelines. This new method enables cost and time reduction and was considered suitable for the clinical laboratory. It is the first published assay for the therapeutic drug monitoring of patients diagnosed with Q fever or Whipple's disease.