Development and Validation of Stability Indicating HPTLC and HPLC Methods for Simultaneous Determination of Telmisartan and Atorvastatin in Their Formulations

Table 7

Results of robustness study by HPTLC.

Condition	Retention factor (𝑅𝑓)		Assay (%)		% RSD
	TLM	ATV	TLM	ATV	TLM	ATV
Mobile phase composition (v/v)
Toluene-methanol-ethyl acetate-acetic acid
(4.9 : 1: 1: 0.5)	0.37	0.64	100.70	101.20	0.41	0.69
(5 : 1 : 1.1 : 0.4)	0.35	0.63	99.30	100.76	1.21	1.08
(5 : 1 : 0.9 : 0.6)	0.35	0.63	98.72	97.91	0.93	0.86
Development distance (cm)
6	0.36	0.64	98.76	101.21	0.71	0.19
7	0.36	0.64	97.86	99.30	0.27	0.87
Time of spotting to chromatogram (min)
9	0.39	0.62	98.61	99.32	1.32	1.47
10	0.36	0.62	100.86	101.20	1.62	0.72
Detection wavelength (nm)
275	0.38	0.63	98.71	99.41	1.01	0.43
280	0.39	0.62	98.76	99.37	0.37	0.86
Temperature (°C)
55	0.37	0.64	99.35	100.67	1.22	0.92
65	0.37	0.63	98.71	99.14	1.07	1.13

TLM: Telmisartan; ATV: Atorvastatin.