Method Development and Validation for the Simultaneous Determination of Fexofenadine Hydrochloride and Montelukast Sodium in Drug Formulation Using Normal Phase High-Performance Thin-Layer Chromatography

Table 3

Robustness testing of method (𝑛=6).

Parameter	SD of peak area^a		% RSD^a
	FEX	MTKT	FEX	MTKT
Mobile phase composition (±0.1 mL)	12.65	3.09	0.27	1.27
Amount of mobile phase (±5%)	15.71	2.40	0.33	0.98
Time from spotting to chromatography (+10 min)	12.36	2.55	0.24	1.04
Time from chromatography to scanning (+10 min)	8.75	2.87	0.18	1.17

^aAverage of three concentrations 2400, 7200, and 10800 ng spot⁻¹ for FEX and 200, 600, and 900 ng spot⁻¹ for MTKT, respectively.