Abstract: AIM: A highly sensitive and reliable LC-MS/MS method was validated for the determination of HHY-002 in rat plasma, a novel antiarrhythmic. METHODS: After addition of diazepam as internal standard(IS); LC separation with a Phenomenex Luna C₁₈ analytical column (150 mm×2.00 mm, 5 μm, 5 micron) and quantification by MS/MS after positive ESI. The mobile phase consisted of acetonitrile∶water∶formic acid (65∶35∶0.1, V/V/V) in an isocratic elution mode pumped at 0.200 mL/min, and with the injection volume of 10 μL and column oven temperature of 35 ℃. RESULTS: The calibration curve ranging from 1.98 to 1013.50 ng/mL. Lower limit of quantification (LLOQ) was 1.98 ng/mL in 100 μL of plasma. Extraction recovery was above 80%, inter- and intra- day accuracy and precise was below 10%.The method recovery was over(81.4±4.5)%.This method was shown to meet all requirements in bioanalytical determination.CONCLUSION: The method was successfully applied to the determination of HHY-002 in rat plasma.

Key words: HHY-002, LC-MS/MS, Rat plasma, Anti-arrhythmic