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 5

Results of precision.

CompoundPrep-1Prep-1Prep-3Prep-4Prep-5Prep-6Avg% RSD

GN-Impurity A0.1980.2010.1890.2130.2050.2090.2034.2
GN-Impurity B0.2090.1950.1920.2010.2060.1940.2003.5
GN-Impurity C0.1890.1950.1860.1920.1980.1840.1912.8
GN-Impurity D0.2080.1900.1920.1930.1880.1860.1934.1
DN-Impurity A0.2150.2140.2150.2090.2120.2050.2121.9
DN-Impurity B0.2040.2000.2020.2030.2050.1910.2012.5
DN-Impurity C0.1950.1860.1980.1990.1840.1940.1933.2
DN-N-oxide0.2160.2140.2180.2190.2110.2100.2151.7
DN-NFM Impurity0.2160.2180.2150.2150.2160.2120.2150.9
DN-NFO Impurity0.1980.1950.2130.1920.2140.2150.2055.2
GN0.2030.2120.2040.2060.2050.2100.2071.7
DN0.1820.1890.1940.1880.1870.2010.1903.4