An HPLC–MS/MS method for simultaneous determination of decitabine and its valyl prodrug valdecitabine in rat plasma

A simple and sensitive HPLC–MS/MS method was developed and validated for the simultaneous determination of decitabine and valdecitabine in rat plasma. The analytes were separated on a C18 column (150 mm × 4.6 mm, 3.5 μm) and a triple-quadrupole mass spectrometer equipped with an electrospray ionization (ESI) source was applied for detection. A clean solid-phase extraction procedure with cation exchange cartridge was employed to extract the analytes from rat plasma with high recovery of decitabine (>82%). The calibration curves were linear over a concentration range of 10–10,000 ng/mL for decitabine and 5–500 ng/mL for valdecitabine. The lower limit of quantitation (LLOQ) of decitabine and valdecitabine was 10 and 5 ng/mL, respectively. The intra-day and inter-day precisions were less than 15% and the relative error (RE) was all within ±15%. The validated method was successfully applied to a pharmacokinetics study in rats after either decitabine or valdecitabine orally administrated to the Sprague-Dawley rats.

► A C18 column (150 mm × 4.6 mm, 3.5 μm) was applied to obtain satisfactory separation.
► A cation exchange solid phase extraction provided high recovery and clean sample.
► The single analysis time was short and close to 15 min.
► The LLOQ was 10 ng/mL for decitabine using only 50 μL of rat plasma.
► The method was sufficiently sensitive to measure low concentration of decitabine.