OBJECTIVE: To establish a HPLC method for determining the concentration of micafungin in human plasma. METHODS: Chlorzoxazone was set as internal standard substance

the plasma sample was proceeded by acetonitrile protein precipitation and isolated by C

18

chromatographic column

with the mobile phase was acetonitrile-5 mmol/L of ammonium acetate （V ∶V = 40 ∶60）

the flow rate was 1. 0 ml/min

the column temperature was 35 ℃ and the detecting wavelength was 273 nm

methodological verification was conducted and applied to determine the concentration of micafungin in human plasma in critical patients. RESULTS: Micafungin was in a good linear relationship in the concentration range of 0. 2-25. 0 μg/ml

with the lowest quantification limit was 0. 2 μg/ml. The recovery rates of low

medium and high concentration quality control samples were respectively 88. 54%

83. 27% and 88. 16%

the intra-day and inter-day precision were both within ±15%. CONCLUSIONS: This method is simple

fast

accurate and reliable

which can be used to monitor the blood concentration of micafungin in critical patients.