Parameters HPLC Method TLC Spectrodensitometric Method Ambroxol HCl Guaifenesin Ambroxol HCl Guaifenesin Precision         Repeatability 1.388 1.984 0.851 1.274 Intermediate precision 1.577 2.082 1.807 1.699 Calibration         Range 5-80 µg.ml-1 10-150  µg.ml-1 1-7 µg/band* 2-10  µg/band* Slope (a) 0.0515 0.033 0.3220 0.2608 Intercept (b) -0.0414 -0.012 0.3472 0.6443 Correlation Coefficient (r) 0.9999 0.9999 0.9999 0.9997 Accuracy 99.95 ± 0.821 100.07 ± 1.093 99.89 ±1.029 100.00 ± 1.161 Specificity 100.40 ± 0.964 100.00 ± 1.041 100.00 ± 1.179 99.90 ± 0.499 LOD  0.757 1.630 0.060 0.110 LOQ 2.295 4.941 0.182 0.334

Regression equations for Ambroxol HCl and Guaifenesin by TLC-spectrodensitometry followed second order equation: For Ambroxol HCl, P= -0.0179C2+0.4652C+0.1324 For Guaifenesin, P= -0.0172C2+0.4677C+0.1386

Table 5: Validation results of the proposed HPLC and TLC-spectrodensitometric methods method.