Stability of seven drugs in human plasma under various storage conditions (n = 5).

Analytes	Spiked conc. (μg mL−1)	Post-preparation stability (4 °C for 24 h)		Long-term stability (−20 °C, 7 days)		Freeze–thaws (−20 °C to 25 °C)
		Mean ± SD	RSD (%)	Mean ± SD	RSD (%)	Mean ± SD	RSD (%)
Aripiprazole	2.5	2.7 ± 0.3	11.1	2.4 ± 0.2	8.3	2.5 ± 0.2	8.0
	45	46.3 ± 1.9	4.1	52.7 ± 1.1	2.1	44.0 ± 2.1	4.8
Paliperidone	2.5	2.8 ± 0.1	3.6	2.6 ± 0.3	11.5	2.4 ± 0.4	16.7
	45	44.2 ± 6.0	13.6	39.8 ± 14.9	37.4	41.1 ± 6.4	15.6
Clozapine	2.5	2.6 ± 0.1	3.9	2.9 ± 0.1	3.4	2.6 ± 0.2	7.7
	45	44.7 ± 3.7	8.3	48.4 ± 3.3	6.8	45.5 ± 4.4	9.7
Ziprasidone	2.5	2.9 ± 0.5	17.2	2.2 ± 0.2	9.1	2.6 ± 0.3	11.5
	45	48.2 ± 4.7	9.8	50.5 ± 1.1	2.2	44.9 ± 3.5	7.8
Olanzapine	2.5	2.4 ± 0.3	12.5	2.6 ± 0.3	11.5	2.0 ± 0.5	25.0
	45	43.7 ± 6.0	13.7	31.1 ± 2.5	8.0	44.4 ± 5.4	12.3
Quetiapine	2.5	2.7 ± 0.1	3.7	2.7 ± 0.2	7.4	2.6 ± 0.1	3.8
	45	44.6 ± 4.6	10.3	48.5 ± 7.0	14.4	46.1 ± 4.9	10.6
Risperidone	2.5	2.7 ± 0.2	7.4	2.8 ± 0.1	3.6	2.6 ± 0.1	3.9
	45	46.1 ± 6.2	13.4	50.2 ± 7.1	14.1	45.5 ± 5.1	11.2