Simultaneous Assay of Dexchlorpheniramine Maleate, Betamethasone, and Sodium Benzoate in Syrup by a Reliable and Robust HPLC Method

Table 8

Results of robustness.

Variation	Specific condition	Dexchlorpheniramine maleate		Sodium benzoate		Betamethasone
		RSD (%) for peak area	RSD (%) for content in syrup	RSD (%) for peak area	RSD (%) for content in syrup	RSD (%) for peak area	RSD (%) for content in syrup
Flow rate (mL/min)	0.8	0.1	0.4	0.1	0.4	0.3	0.4
	1.0 (normal)	0.2	0.6	0.2	0.6	0.4	0.5
	1.2	0.4	0.4	0.1	0.9	0.3	0.8
pH of 0.02 M phosphate buffer solution	2.65	0.2	0.6	0.2	0.6	0.2	0.6
	2.70 (normal)	0.1	0.5	0.3	0.9	0.4	0.3
	2.75	0.3	0.3	0.5	0.9	0.4	0.5
Percentage of 0.02 M phosphate buffer in mobile phase	64	0.1	0.5	0.2	0.9	0.2	0.5
	65 (normal)	0.1	0.6	0.3	0.5	0.3	0.7
	66	0.1	0.4	0.2	1.1	0.5	0.4
Wavelength of detector	252 nm	0.5	0.4	0.2	0.5	0.2	0.5
	254 nm (normal)	0.1	0.3	0.3	0.5	0.3	0.4
	256 nm	1.0	0.4	0.4	0.9	0.2	0.5