New Modified UPLC/Tandem Mass Spectrometry Method for Determination of Risperidone and Its Active Metabolite 9-Hydroxyrisperidone in Plasma: Application to Dose-Dependent Pharmacokinetic Study in Sprague-Dawley Rats

Table 5

Stability of RIS and 9-OH-RIS in rat plasma.

Stability	Nominal conc.; (ng/mL)	RIS			9-OH-RIS
		Measured conc. (ng/mL); (mean ± SD)	Precision; (CV%)	Accuracy; (%)	Measured conc.(ng/mL); (mean ± SD)	Precision; (CV%)	Accuracy; (%)
Bench top	2	2.19 ± 0.07	8.18	109.50	2.15 ± 0.03	6.76	107.5
(6 h)	400	396 ± 1.59	5.85	99.00	397 ± 0.05	8.54	99.25
Freeze thaw	2	2.34 ± 0.07	6.58	117.00	1.97 ± 1.08	7.98	98.5
(3 cycles)	400	394 ± 20.12	5.51	98.50	390 ± 0.07	5.90	97.5
In injector	2	1.98 ± 1.07	4.14	99.00	1.89 ± 2.35	7.95	94.5
(48 h)	400	377 ± 15.00	7.18	94.25	392 ± 12	7.12	98.0
60 days	2	1.88 ± 0.08	3.95	94.00	1.79 ± 3.31	6.55	89.5
at −80°C	400	390 ± 12.15	4.59	97.50	393 ± 10.21	4.24	98.25