Sequential Spectrophotometric Method for the Simultaneous Determination of Amlodipine, Valsartan, and Hydrochlorothiazide in Coformulated Tablets

Table 4

Assay validation sheet of the proposed spectrophotometric method for the simultaneous determination of AML, VAL, and HCT.

Parameter	Proposed method
	AML	VAL	HCT
Accuracy (mean ± RSD)	99.93±1.188	99.66±0.956	100.24±0.679
Precision
Repeatability^a	0.535	0.651	0.867
Intermediate precision^b	1.061	1.225	1.002
Robustness^c	0.704	0.633	0.807
Linearity
Slope	0.0162	0.0258	0.0108
Intercept	0.0010	0.0051	0.0030
Correlation coefficient (𝑟)	0.9998	0.9998	0.9998
Range (μg/mL)	4–32	4–44	6–20

aThe intraday (𝑛=3) average of three concentrations (12, 16, 20 𝜇g/mL) for AML, VAL, and HCT repeated three times within the day.
bThe interday (𝑛=3) average of three concentrations (12, 16, 20 𝜇g/mL) for AML, VAL, and HCT repeated three times in three days.
cRobustness (𝑛=3) average of three concentrations (12, 16, 20 𝜇g/mL) for AML, VAL, and HCT analyzed using 75 and 70% methanol.