A Liquid Chromatography-Tandem Mass Spectrometry Method for Evaluation of Two Brands of Enalapril 20 mg Tablets in Healthy Human Volunteers

Table 4

Stability of enalapril under different storage conditions ().

Storage Condition	QC	Measured QC at	Mean ± SD	Accuracy	Stability
	(ng/ml)	0.0 h (ng/ml)	(ng/ml)	(%)	(%)
Autosampler stability 24 h at 4°C	3			93.03	95.83
	100			100.04	98.34
	160			105.09	95.40
Freeze and thaw stability at −20°C (3 cycles)	3			102.22	96.45
	100			107.96	98.54
	160		17.110 ± 4.011
Room temperature stability for 10 h	3			97.38	99.57
	100			101.32	101.64
	160			100.36	103.66
Accelerated stability at  −30.0°C for 30 days	3			94.69	97.81
	100			99.53	96.59
	160			101.55	85.10