Application of a Stability-Indicating HPTLC Method for Simultaneous Quantitative Determination of Olmesartan Medoxomil and Hydrochlorothiazide in Pharmaceutical Dosage Forms

Table 4

Results from robustness study.

Condition	Retention factor (𝑅𝑓)		Assay^a (%)		% RSD
	OLM	HTZ	OLM	HTZ	OLM	HTZ
Mobile phase composition (v/v/v/v)
Toluene : methanol : ethyl acetate : acetone
(2.4 : 1 : 1 : 1.5)	0.31	0.54	100.70	101.20	0.41	0.69
(2.5 : 1 : 1 : 2.5)	0.32	0.53	99.30	100.76	1.21	1.08
(2.5 : 0.9 : 0.9 : 1.5)	0.31	0.54	98.72	97.91	0.93	0.86
Development distance (cm)
6	0.30	0.54	98.76	101.21	0.71	0.19
7	0.31	0.52	97.86	99.30	0.27	0.87
Time of spotting to chromatogram (min)
9	0.30	0.52	98.61	99.32	1.32	1.47
10	0.28	0.52	100.86	101.20	1.62	0.72
Detection wavelength (nm)
275	0.29	0.53	98.71	99.41	1.01	0.43
280	0.29	0.54	98.76	99.37	0.37	0.86

^aMean of three determinations, RSD: relative standard deviation.