Application of Cerium (IV) as an Oxidimetric Agent for the Determination of Ethionamide in Pharmaceutical Formulations

Table 3

Method robustness and ruggedness expressed as intermediate precision (% RSD).

Method	ETM; taken (mg or μg/mL)	Robustness (% RSD)		Ruggedness (% RSD)
		Parameters altered		Inter-analysts; ()	Interburettes/cuvettes; ()
		Contact time	Volume of
Titrimetry	2.0	0.88	0.67	1.33	1.91
	4.0	1.05	0.88	1.66	1.83
	6.0	1.24	1.58	1.11	2.11
Spectrophotometry	1.0	1.53	1.85	1.44	1.97
	2.0	2.31	1.17	0.97	1.73
	3.0	2.24	1.74	1.47	1.65

In titrimetry, ETM taken/found is in mg and the same was in μg/mL in spectrophotometry. Contact time used: 4, 5, and 6 min in titrimetric method; 8, 10, and 12 min in spectrophotometric method. Volumes of H₂SO₄ were 4, 5, and 6 mL (2 M) in titrimetric method and 2.5, 3.0, and 3.5 mL (5 M) in spectrophotometric method.