Parameters CARV HCT 3D 4D 1DD 3D 4D 1DD Wavelength (nm) 245.9 247.4 236.1 230.2 226.9 261.1 Concentration range (µg.mL-1) 1.0- 20.0 1.0- 20.0 Regression equation (Y)a             Slope (b) 0.090 0.066 1.044 0.103 0.066 1.313 Intercept (a) 0.028 0.014 0.013 0.033 0.024 0.017 Correlation coefficient (r) 0.9995 0.9999 0.9998 0.9998 0.9998 0.9999 Accuracy (mean%, n=15) 100.50 100.10 99.97 100.92 100.17 100.05 Intraday precision (RSD%,n=12) 0.53 0.49 0.85 0.68 0.70 0.93 Interday precision (RSD%,n=12) 0.62 0.78 0.57 0.87 0.66 0.71 LOD (µg.mL-1) 0.18 0.24 0.13 0.21 0.20 0.11 LOQ (µg.mL-1) 0.55 0.94 0.39 0.64 0.61 0.33 a Y= a+b X, where Y is the amplitude and X is the drug concentration.

Table 1: Analytical parameters for the calibration graphs (n=7) for the determination of CARV and HCT using 3D, 4D and 1DD methods.