Stability-Indicating HPLC Determination of Trandolapril in Bulk Drug and Pharmaceutical Dosage Forms

Table 5

Factorial design data for robustness of chromatographic separation.

(a)

Selected parameters and their variations	−1 (lower limit)	+1 (upper limit)
Acetonitrile in mobile phase (%) ()	45	55
Peak modifier (concentration of TEA) ()	200	300
Final pH of the mobile phase ()	2.75	3.25
Flow rate (mL/min) ()	0.9	1.1

(b)

Exp. number	Run order	Factors				Responses
								Area
1	13	45	200	2.75	0.9	5.2	1.12	211945
2	14	55	200	2.75	0.9	4.3	1.09	208410
3	8	45	300	2.75	0.9	5.1	1.08	209599
4	10	55	300	2.75	0.9	4.2	1.06	208477
5	3	45	200	3.25	0.9	5.1	1.12	208104
6	2	55	200	3.25	0.9	4.4	1.09	209648
7	1	45	300	3.25	0.9	5.1	1.07	201045
8	7	55	300	3.25	0.9	4.8	1.11	208154
9	12	45	200	2.75	1.1	4.7	1.10	208450
10	11	55	200	2.75	1.1	4.1	1.07	207649
11	5	45	300	2.75	1.1	4.5	1.07	208478
12	4	55	300	2.75	1.1	4.2	1.10	208451
13	9	45	200	3.25	1.1	4.6	1.10	210450
14	16	55	200	3.25	1.1	4.05	1.06	207145
15	15	45	300	3.25	1.1	4.6	1.10	209457
16	6	55	300	3.25	1.1	4.1	1.07	207124

= retention time of drug, = tailing factor for drug, and area count.