Stability of lapachol in the plasma and brain under different storage conditions (n = 4).

Matrix	Spiked	Room temperature for 12 h			Storage for 24 h at 4 °C			Storage for 48 h at −20 °C
		Measured mean ± SD	RSD (%)	RE (%)	Measured mean ± SD	RSD (%)	RE (%)	Measured mean ± SD	RSD (%)	RE (%)
Plasma (ng ml−1)	5	5.40 ± 0.42	7.81	8.01	5.37 ± 0.55	10.2	7.43	5.17 ± 0.67	12.88	3.39
	100	106.48 ± 4.64	4.36	6.48	87.31 ± 1.88	2.16	−12.69	105.08 ± 5.75	5.47	5.08
	1000	1088.33 ± 79.64	7.32	8.83	971.23 ± 40.16	4.13	−2.88	909.58 ± 40.63	4.47	−9.04
Plasma (μg ml−1)	1	0.92 ± 0.12	12.56	−7.84	0.92 ± 0.06	6.19	−7.98	0.88 ± 0.03	3.87	12.35
	20	22.51 ± 0.25	1.12	12.57	20.74 ± 0.61	2.93	3.69	22.64 ± 0.25	1.09	13.19
	100	87.80 ± 3.87	4.41	−12.20	88.65 ± 1.82	2.05	−11.36	94.71 ± 1.55	1.64	−5.29
Brain (ng ml−1)	5	5.63 ± 0.32	5.75	12.52	4.92 ± 0.75	15.22	−1.7	5.39 ± 0.35	6.5	7.72
	100	89.43 ± 3.59	4.02	−10.58	92.59 ± 2.98	3.22	−7.41	103.64 ± 8.46	8.17	3.63
	1000	1063.18 ± 45.18	4.25	6.32	964.45 ± 81.65	8.47	−3.56	966.98 ± 55.68	5.76	−3.3