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Table 3 Regression parameters for determination of the studied drugs by the proposed TLC densitometric method

From: A green TLC densitometric method for the simultaneous detection and quantification of naphazoline HCl, pheniramine maleate along with three official impurities

Parameter NPZ impurity B NPZ PHN PHN impurity A PHN impurity B
Range 0.1–10.0 µg band−1 2.0–50.0 µg band−1 10.0–110.0 µg band−1 0.2–50.0 µg band−1 0.2–50.0 µg band−1
Slope No. 1a =  − 172.85
No. 2a = 3480.76
No. 1a =  − 13.91
No. 2a = 1389.10
No. 1a =  − 1.82
No. 2a = 584.57
No. 1a = − 9.78
No. 2a = 943.45
No. 1a =  − 11.64
No. 2a = 962.46
Intercept 1343.80 3305.64 4730.10 14,708.36 11,166.09
SE of the slope No. 1a = 11.13
No. 2a = 112.36
No. 1a = 0.54
No. 2a = 26.87
No. 1a = 0.10
No. 2a = 15.50
No. 1a = 0.45
No. 2a = 23.73
No. 1a = 0.59
No. 2a = 25.15
SE of the Intercept 182.40 249.72 492.06 232.59 202.55
Specificity b (mean ± SD) 99.11 ± 1.382 100.72 ± 0.221 100.25 ± 1.054 99.10 ± 1.152 98.89 ± 1.963
Accuracy 99.74 101.15 100.42 99.97 100.99
Repeatability (RSD) 1.28 1.47 1.29 0.74 1.03
Intermediate precision (RSD) 1.77 0.55 1.84 0.96 1.79
Robustness 0.98 0.78 0.84 1.07 1.45
LOD (µg band−1) 0.01 0.60 2.38 0.05 0.06
LOQ (µg band−1) 0.03 1.82 7.21 0.15 0.18
Correlation coefficient (r) 0.999 0.999 0.999 0.999 0.999
  1. aSlope 1 and 2 are the coefficients of a polynomial regression, A = ax2 + bx + c, where A is the integrated peak area, x is the concentration of the drug (μg band−1), a and b are coefficients 1 and 2, respectively, and c is the intercept
  2. bAverage of determinations in seven laboratory-prepared mixtures