Stress Degradation Behavior of Paliperidone, an Antipsychotic Drug, and Development of Suitable Stability-Indicating RP-LC Method

Table 4

Validation data results of related substances and assay of paliperidone.

Compound	Related substances results					Assay results
	IMP-A	IMP-B	IMP-C	IMP-D	IMP-E	paliperidone
Precision (mean results ± %RSD)
Method precision (𝑛=6)	0.164±1.24	0.163±0.61	0.546±3.85	0.149±0.67	0.059±1.69	99.0±0.21
Intermediate Precision (𝑛=6)	0.158±0.63	0.159±0.00	0.526±0.57	0.151±0.66	0.062±0.00	100.3±0.35
Overall results (𝑛=12)	0.160±1.25	0.161±1.24	0.536±3.39	0.150±1.33	0.061±3.28	99.7±0.75
Limit of detection (LOD)
LOD (μg mL^−1)	0.030	0.039	0.155	0.071	0.046	0.065
LOD (% w.r.t. test)	0.003	0.004	0.016	0.007	0.005	0.007
Limit of quntitations (LOQ)
LOQ (μg mL^−1)	0.090	0.119	0.470	0.214	0.141	0.197
LOQ (% w.r.t. test)	0.009	0.012	0.047	0.021	0.014	0.020
Linearity: for related substances LOQ to 250% of specification level and for assay 50 to 150% of TAC
Correlation coefficient (r)	0.99966	0.99978	0.99973	0.99936	0.99925	0.99996
Slope	22910.49	35819.23	19598.94	30803.29	36086.78	31580.49
Intercept	−100.38	−653.37	1214.32	−172.37	−631.62	−1131.83
Accuracy (mean recovery ± %RSD): LOQ to 150 % of specification level
LOQ	92.59±6.93	86.11±5.59	106.51±7.36	90.48±5.27	92.31±8.33	—
50%	93.86±2.14	95.22±0.75	114.93±1.04	100.00±1.35	91.11±1.69	—
100%	104.17±1.93	97.60±0.77	107.54±0.68	99.55±1.42	94.67±0.70	—
150%	103.36±0.65	97.68±0.51	104.37±0.44	99.85±1.44	94.81±0.54	—

% w.r.t. test LOD LOQ values are in % with respect to test concentration of 1000 μg mL⁻¹.
TAC, Target analytical concentration that is, 100 μg mL⁻¹.