Novel LC Method Development and Validation for Simultaneous Determination of Montelukast and Doxofylline in Bulk and Pharmaceutical Dosage Forms

Table 4

Robustness results.

		Retention time %RSD	Area %RSD
Different flow rates
0.8 mL/min	Montelukast	0.07	0.48
	Doxofylline	0.15	0.16
1.2 mL/min	Montelukast	0.12	0.31
	Doxofylline	0.24	0.39
Different pH values
4.3	Montelukast	0.29	0.98
	Doxofylline	0.51	0.46
4.7	Montelukast	0.1	0.99
	Doxofylline	0.24	0.24
Different wave lengths
278 nm	Montelukast	0.32	0.52
	Doxofylline	0.12	0.1
282 nm	Montelukast	0.29	0.76
	Doxofylline	0.38	0.49
Different temperatures
39.5^°C	Montelukast	0.09	0.34
	Doxofylline	0.19	0.15
40.5^°C	Montelukast	0.03	0.15
	Doxofylline	0.06	0.21