LC-MS/MS Method for Determination of Hydroxychloroquine and Metabolites: Application in a Pharmacokinetic Study

Table 5

Stability of analytes in different conditions (n = 5).

Analytes	Nominal concentration (ng/mL)	Short-term stability (6 h)		Long-term stability (30 day at −80°C)		Freeze-thaw stability (3 cycles)
		Measured concentration (mean ± SD, ng/mL)	RSD (%)	Measured concentration (Mean ± SD, ng/mL)	RSD (%)	Measured concentration (Mean ± SD, ng/mL)	RSD (%)
BDCQ	2.5	2.61 ± 0.05	2.13	2.54 ± 0.04	1.80	2.59 ± 0.04	1.71
	2000	1842.63 ± 48.07	2.61	1765.50 ± 32.09	1.82	1733.13 ± 29.97	1.73
DCQ	2.5	2.63 ± 0.07	2.89	2.55 ± 0.03	1.42	2.57 ± 0.04	1.61
	2000	2098.46 ± 164.60	7.84	2142.71 ± 148.78	6.94	1943.91 ± 77.36	3.98
DHCQ	2.5	2.60 ± 0.05	2.12	2.48 ± 0.05	2.22	2.63 ± 0.06	2.40
	2000	1859.79 ± 70.66	3.80	1876.02 ± 88.45	4.71	1753.78 ± 69.66	3.97
HCQ	5	5.31 ± 0.14	2.67	5.08 ± 0.10	2.15	5.12 ± 0.06	1.24
	4000	4395.41 ± 243.53	5.54	4170.81 ± 313.74	7.52	4362.96 ± 325.76	7.47