UPLC-Tandem Mass Spectrometry Method for Simultaneous Determination of Fluoxetine, Risperidone, and Its Active Metabolite 9-Hydroxyrisperidone in Plasma: Application to Pharmacokinetics Study in Rats

Table 4

Data showing the stability of FLX, RIS, and 9-OH-RIS in human rat plasma at different QC levels ( = 6).

Parameters	Stability
	1.0 ng/mL		100.0 ng/mL		500.0 ng/mL
	%	CV%	%	CV%	%	CV%
FLX
Bench top (6 hrs)	99.87	4.75	99.87	4.75	101.55	6.93
Freeze-thaw (3 cycles)	97.99	0.20	97.99	0.20	102.61	5.24
6 weeks at −80°C	93.50	6.43	93.50	6.43	106.82	4.76
In autosampler (24 hrs)	98.04	1.58	98.04	1.58	97.95	2.58
RIS
Bench top (6 hrs)	101.15	10.59	101.15	10.59	98.57	4.15
Freeze-thaw (3 cycles)	95.33	6.61	95.33	6.61	98.75	7.53
6 weeks at −80°C	93.99	3.31	93.99	3.31	102.60	4.00
In autosampler (24 hrs)	97.74	2.51	97.74	2.51	98.23	1.43
9-OH-RIS
Bench top (6 hrs)	99.68	3.94	99.68	3.94	109.23	6.05
Freeze-thaw (3 cycles)	97.85	10.15	97.85	10.15	112.61	4.12
6 weeks at −80°C	103.58	6.85	103.58	6.85	110.14	7.71
In autosampler (24 hrs)	99.12	4.11	99.12	4.11	102.10	9.41