Liquid Chromatography-Tandem Mass Spectrometry Method for the Determination of Vardenafil and Its Application of Bioequivalence

Table 3

Stability test of vardenafil in plasma.

		LQC (AUC ratio)	HQC (AUC ratio)
Post 8 h at 25°C	Mean	0.92	29.04
	SD	0.09	1.68
	RSD %	10.68	5.79
	Accuracy %	98.2	100.1
Post 10 h at 10°C	Mean	0.85	29.92
	SD	0.04	3.25
	RSD %	4.94	10.89
	Accuracy %	90.5	103.1
Three times freeze-thaw at −20°C	Mean	0.92	31.45
	SD	0.11	0.76
	RSD %	12.72	2.44
	Accuracy %	98.1	108.4
One-month stability at −20°C	Mean	0.91	29.08
	SD	0.02	0.54
	RSD %	2.66	1.86
	Accuracy %	96.9	100.2
Two-month stability at −20°C	Mean	0.97	24.21
	SD	0.08	2.63
	RSD %	8.55	10.22
	Accuracy %	103.4	88.7

SD: standard deviation; RSD: relative standard deviation; %: percentage; LQC: low quality control; HQC: high quality control; n = 3.