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

Table 6

Summary of precision.

Run order	PSU			FEX
	50%	100%	150%	50%	100%	150%
HPLC-1, day 1	100.05	99.98	100.02	99.99	99.98	99.98
HPLC-1, day 2	99.99	99.92	100.07	99.99	100.01	100.51
HPLC-2, day 1	99.94	100.10	100.56	99.98	100.10	99.97
HPLC-2, day 2	100.01	99.90	100.10	99.99	100.06	99.94
% RSD of total variation	0.0457	0.090	0.2500	0.005	0.0531	0.2735
% RSD of system	0.0777	0.0849	0.3807	0.0071	0.0849	0.0071
	0.0141	0.0141	0.0211	0.0010	0.0354	0.4021
% RSD of inter assay precision	0.0424	0.0424	0.0353	0.00	0.0212	0.3738
	0.0495	0.1414	0.3241	0.007	0.0283	0.0212

row for HPLC variation on day 1 and lower row for HPLC variation on day 2
row for interday variation on HPLC-1 and lower row for interday variation on HPLC-2.