Analytical Quality by Design Approach of Reverse-Phase High-Performance Liquid Chromatography of Atorvastatin: Method Development, Optimization, Validation, and the Stability-Indicated Method

Table 2

Critical influencing variable and their actual and predicted values of responses.

Standard order	Critical influencing variable			Response
	Acetonitrile (%)	Flow rate (ml/min)	Wavelength (nm)	Area (AU)		Retention time		Tailing factor
				Actual value	Predicted value	Actual value	Predicted value	Actual value	Predicted value
1	50	0.35	240	1975990	1975589	2.19	2.18	1.95	1.94
2	90	0.35	240	1501486	1502578	4.18	4.19	2.42	2.41
3	50	1	240	2149670	2148578	3.23	3.22	2.12	2.12
4	90	1	240	1730395	1730796	5.33	5.34	2.47	2.48
5	50	0.68	235	2037161	2038807	2.45	2.47	2.08	2.09
6	90	0.68	235	1565069	1565223	4.84	4.84	2.51	2.52
7	50	0.68	245	2004970	2004816	2.83	2.83	2.04	2.05
8	90	0.68	245	1589253	1587607	4.62	4.6	2.44	2.43
9	70	0.35	235	1755465	1754220	2.9	2.89	2.21	2.21
10	70	1	235	1984765	1984211	4.02	4.02	2.34	2.33
11	70	0.35	245	1777250	1777804	2.98	2.99	2.14	2.15
12	70	1	245	1947774	1949019	4.04	4.05	2.26	2.26
13	70	0.68	240	1804782	1804782	3.54	3.54	2.01	2.01
14	70	0.68	240	1804782	1804782	3.54	3.54	2.02	2.01
15	70	0.68	240	1804782	1804782	3.54	3.54	2.01	2.01
16	70	0.68	240	1804782	1804782	3.54	3.54	2.01	2.01
17	70	0.68	240	1804782	1804782	3.54	3.54	2.01	2.01