Stability of nafamostat in intravenous infusion solutions, human whole blood and extracted plasma: implications for clinical effectiveness studies

Aim: To describe the stability of nafamostat in infusion solutions, during blood sample collection and in extracted plasma samples in the autosampler. Methods: Nafamostat infusion solutions were stored at room temperature in the light for 24 h. For sample collection stability, fresh blood spiked with nafamostat was subjected to combinations of anticoagulants, added esterase inhibitor and temperature. Nafamostat was monitored in the extracted plasma samples in the autosampler. Results: Nafamostat was stable in infusion solutions. Nafamostat in whole blood was stable for 3 h before centrifugation when collected in sodium fluoride/potassium oxalate tubes (4 degrees C). Nafamostat in extracted plasma samples degraded at 4.7 +/- 0.7% per h. Conclusion: Viable samples can be obtained using blood collection tubes with sodium fluoride, chilling and processing promptly.