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. Author manuscript; available in PMC: 2007 Sep 17.
Published in final edited form as: Neuroscience. 2007 Apr 16;146(3):1316–1332. doi: 10.1016/j.neuroscience.2007.03.003

Table 2.

Stability of Haloperidol and Risperidone

A: Stability as Concentrated Solutions in 0.1 M acetic acid at 4°C
Haloperidol Risperidone
Time (weeks) Concentration (mg/ml) SD R.S.D. (%) Time (weeks) Concentration (mg/ml) SD RSD. (%)
0 4.7 0.03 0.70 0 5.6 0.08 1.33
1 4.9 0.04 0.71 1 5.4 0.08 1.40
2 4.9 0.16 3.24 2 5.5 0.06 1.06
4 4.8 0.01 2.20 4 5.7 0.19 3.28
B: Stability of Dilutions in Rodent Drinking Water
Haloperidol (Tap water) Haloperidol (distilled/deionized Water)
Time (hours) Concentration (μg/ml) SD R.S.D. (%) Time (hours) Concentration (μg/ml) SD RSD. (%)
0 20.1 0.26 1.31 0 20.5 0.22 1.06
6 20.1 0.16 0.81 6 20.4 0.09 0.44
24 19.7 0.11 0.57 24 19.9 0.13 0.68
48 19.6 0.30 1.50 48 20.0 0.03 0.16
72 20.3 0.10 0.48 72 20.5 0.02 0.11
96 20.1 0.07 0.34 96 20.5 0.09 0.44
Risperidone (Tap water) Risperidone (distilled/deionized Water)
0 22.2 0.33 1.47 0 22.8 0.04 0.18
6 22.5 0.27 1.19 6 22.8 0.22 0.95
24 22.1 0.08 0.34 24 22.2 0.15 0.68
48 22.5 0.36 1.59 48 22.3 0.02 0.08
72 22.6 0.16 0.70 72 22.3 0.39 1.73
96 22.6 0.22 0.07 96 22.7 0.22 0.98

N=3 samples per determination; SD= Standard Deviation; RSD= relative standard deviation