Research Article

Development and Validation of a Stability-Indicating RP-HPLC Method for the Simultaneous Estimation of Guaifenesin and Dextromethorphan Impurities in Pharmaceutical Formulations

Table 9

Regression statistics.

SubstanceLinearity range ( g mL−1)Correlation coefficient ( ) -intercept bias in %

GN-Impurity A0.93 to 239.610.9990.9
GN-Impurity B2.01 to 242.780.9991.0
GN-Impurity C1.26 to 241.921.0000.7
GN-Impurity D0.79 to 242.550.9990.8
DN-Impurity A0.17 to 14.101.0000.4
DN-Impurity B0.25 to 10.101.0000.1
DN-Impurity C0.27 to 12.231.0000.8
DN-N-oxide0.19 to 12.491.0000.6
DN-NFM Impurity 0.19 to 12.190.9981.5
DN-NFO Impurity 0.48 to 12.221.0000.9
GN1.53 to 244.780.9991.6
DN0.18 to 12.151.0000.1