Determination of in vitro human whole blood-to-plasma ratio of THJ-018 utilizing gas chromatography-Mass spectrometry.

OBJECTIVES: This study was aimed to determine in vitro human whole blood-to-plasma ratio (K(WB)/(P)) of THJ-018 by gas chromatography/mass spectrometry (GC/MS). MATERIALS AND METHODS: The samples (human blood) were sprayed with THJ-018 and an internal standard and extracted using solid-phase extraction. THJ-018 was determined in the final extracts by GC/MS. RESULTS: The value for K(WB)/(P) was 1.56 (1.38-1.81), and red blood cell partitioning was 1.01 (1.01-1.02). The distribution of THJ-018 between whole blood and plasma was observed to be affected by temperature. CONCLUSION: The data analysis supports the proposition that the ratio of the plasma to whole blood concentrations (1.56) is a suitable parameter characterizing THJ-018 distribution in whole blood. For toxicological analysis, it would be best to refrain from converting any drug concentration measured in whole blood to that anticipated in plasma or serum; however, toxic and therapeutic concentrations should be determined for the individual specimens collected.