Ecofriendly colorimetric set-up coupled with mathematical filtration strategy for simultaneous determination of ipratropium and fenoterol in their novel anti-asthmatic metered dose inhaler

Table 1 Method validation parameters and regression for the determination of a binary mixture of ipratropium and fenoterol by the proposed colorimetric method

Parameter	Colorimetric method
Parameter	IPR	FEN
Wavelength (nm)	464.3	514.0
Linearity range (µg/mL)	5.0–55.0	10.0–40.0
Regression equation parameters
Slope (b)^a	0.006	0.0225
SE of the slope	0.00002	0.0002
Intercept (a)^a	0.3814	0.0151
SE of the intercept	0.0006	0.0053
Correlation coefficient (r)	1.0000	0.9998
Accuracy (mean ± %RSD)^b	100.28 ± 1.83	100.29 ± 1.70
Precision (± %RSD)
Repeatability^c	0.914	1.057
Intermediate precision^d	1.234	1.794
Specificity (mean ± %RSD)	100.28 ± 1.387	99.78 ± 1.337
LOD^e	0.335	0.604
LOQ^e	1.014	1.830
Robustness (%RSD)
Scanning wavelength (± 2 nm)	1.801	1.790
pH (± 0.1)	0.464	1.051

^aRegression equation for colorimetric method: A = a + bc, where ‘A’ is the average absorbance, c’ is the concentration (μg/mL), ‘a’ is the intercept and ‘b’ is the slope
^bAccuracy [average of five different concentrations of three replicates each (n = 15)]
^cIntra-day precision [average of three different concentrations of three replicates each (n = 9) within the same day]
^dInter-day precision [average of three different concentrations of three replicates each (n = 9) repeated on three successive days]
^eLOD and LOQ are calculated according to ICH, 3.3 × SD of the residuals/slope and 10 × SD of the residuals/slope, respectively

ISSN: 2661-801X