Quantification of Warfarin in Dried Rat Plasma Spots by High-Performance Liquid Chromatography with Tandem Mass Spectrometry

Table 3

Stability for quality controls (LQC and HQC) of warfarin and its alcohol metabolites.

Time	Target (ng/mL)	Stability
		Bench top		Refrigerator		Three freeze-thaw cycles
		% of target	% RSD	% of target	% RSD	% of target	% RSD
24 h	50	—	—	—	—	127.9	11.9
	4000	—	—	—	—	120.9	1.4
1 week	50	104.1	6.8	121.9	4.4	—	—
	4000	101.0	4.2	94.6	3.6	—	—
2 weeks	50	119.8	20.0	121.2	5.2	—	—
	4000	90.1	3.5	90.1	2.1	—	—
3 weeks	50	86.8	13.1	105.6	7.9	—	—
	4000	99.3	3.6	85.0	4.5	—	—

Data are presented as means () at LQC and HQC levels.