Eco-friendly resolution of spectrally overlapping signals of a combined triple-action over-the-counter pharmaceutical formulation for symptomatic management of COVID-19 pandemic: application to content uniformity testing

Table 1 Regression parameters and assay validation report of the proposed spectrophotometric methods for determination of pure PAR, ASP and DIPH samples

Parameter	D¹ method	DWRS method	DD-RD method
Parameter	PAR	ASP	DIPH
Wavelength (λ)	259.7 nm	ΔA_{(214.1–220.1 nm)}	ΔP_{(214.5–226 nm)}
Linearity range (μg/mL)	3.0–40.0	4.0–40.0	1.0–40.0
Slope	0.0398	0.0473	0.0114
SE of slope	0.000216	0.000218	0.000008
Intercept	0.0233	− 0.0459	− 0.0042
SE of intercept	0.004095	0.004203	0.000197
Correlation coefficient (r)	0.9999	0.9999	1.000
Accuracy^a (Mean ± SD)	100.00 ± 1.04	99.42 ± 1.23	99.48 ± 1.12
Precision^a
± (%RSD)^b	0.83	0.40	0.94
± (%RSD)^c	1.18	1.67	1.62
LOD (μg/mL)^d	0.50	0.41	0.19
LOQ (μg/mL)^d	1.52	1.26	0.57

^a Mean and %RSD correspond to the mean and %RSD of the percent recovery
^b Intra-day precision [average of 3 different concentrations of 3 replicate each (n = 9) within the same day]
^c Inter-day precision [average of 3 different concentrations of 3 replicate each (n = 9) repeated on 3 successive days]
^d Limit of detection and quantitation are determined via calculations, LOD = (SD of regression residuals/ slope) × 3.3; LOQ = (SD of regression residuals/ slope) × 10

ISSN: 2661-801X