Titrimetric and Spectrophotometric Methods for the Assay of Ketotifen Using Cerium(IV) and Two Reagents

Table 4

Method robustness and ruggedness expressed as intermediate precision.

Method	KTF taken; mg/µg mL^−1	Robustness		Ruggedness
		H2SO4 volume, mL; (% RSD), 𝑛=3	Reaction time, min; (% RSD), 𝑛=3	Ineranalysis (% RSD), 𝑛=4	Intercuvettes/burettes (% RSD), 𝑛=4
A	5.0	0.88	1.63	0.81	0.85
	10.0	1.33	1.83	1.93	1.23
	15.0	1.03	0.59	0.89	0.96
B	2.0	2.60	2.11	2.11	2.38
	4.0	2.71	1.36	2.63	1.82
	6.0	1.79	1.80	1.58	2.83
C	4.0	2.66	2.70	2.01	2.71
	6.0	2.45	1.83	2.79	1.99
	8.0	1.72	1.27	1.69	2.96

In titrimetry, standing times were 8, 10, and 12 min.
In spectrometric methods B and C, reaction time, 10 ± 1 min; volume of H₂SO₄ 2 ± 0.2 mL and 1 ± 0.2 mL varied, respectively.