A Simple and Improved HPLC-PDA Method for Simultaneous Estimation of Fexofenadine and Pseudoephedrine in Extended Release Tablets by Response Surface Methodology

Table 3

CCD design matrix with two independent variables and observed responses.

Std order	Run order	Blocks	MeOH (% V/V)	ACN (% V/V)	of PSU (min)	of FEX (min)	(%)
2	1	1	15	20	3.30	37.6	38.16
13	2	1	10	40	2.50	3.40	4.55
11	3	1	10	40	2.40	3.30	4.5
8	4	1	10	60	2.60	4.10	6.27
9	5	1	10	40	2.50	3.50	4.7
3	6	1	5	60	2.70	2.98	0.75
5	7	1	5	40	2.54	3.26	3.34
12	8	1	10	40	2.50	3.40	4.55
4	9	1	15	60	2.70	3.80	5.2
7	10	1	10	20	3.00	20.2	29.4
10	11	1	10	40	2.50	3.40	4.55
6	12	1	15	40	2.70	4.50	8.57
1	13	1	5	20	3.10	35.0	36.25