Journal of Chemistry / 2017 / Article / Tab 9 / Research Article
A Simple and Improved HPLC-PDA Method for Simultaneous Estimation of Fexofenadine and Pseudoephedrine in Extended Release Tablets by Response Surface Methodology Table 9 Result of robustness study.
Parameter Changed value Retention Tailing factor Peak purity PSU FEX PSU FEX PSU FEX pH ± 0.4 7.2 3.0 4.6 1.63 1.15 0.999 1.000 6.4 2.5 4.6 1.62 1.14 0.999 1.000 Flow ± 0.5 1.5 1.8 3.2 1.48 1.10 1.000 1.000 0.5 4.8 7.0 1.71 1.21 0.999 0.999 Buffer conc. ± 10 mM 30 mM 2.8 4.9 1.59 1.13 1.000 0.999 10 mM 2.6 4.4 1.61 1.21 1.000 1.000 Zorbax Eclipse XDB (Double Encapped) Nonpolar 2.8 4.8 1.68 1.10 1.000 0.999 ProntoSIL C18-EPS (with amide embedded group) Polar 3.5 4.1 1.36 1.31 0.999 1.000