Sensitive and Selective Analytical Method for the Quantification of Two Potential Genotoxic Impurities in Azilsartan Drug Substance by using LC-MS/MS with Multiple Reaction Monitoring (MRM mode)

The main aim of the present study to Synthesize,method development and method validation for quantification of two potential genotoxic impurities i.e., Methyl(Z)-2-ethoxy-1-((2'-(N'-hydroxycarbamimidoyl)-[1,1'-biphenyl]-4-yl) methyl)-1H-benzo[d]imidazole-7-carboxylate(Impurity-A) and 2-ethoxy-1-((2'-(N'-hydroxycarbamimidoyl[)-[1,1'-biphenyl]-4-yl)methyl)-1H-benzo[d]imidazole-7-carboxylicacid(Impurity-B) by using LC-MS/MS MRM mode at trace level determination inAzilsartan drug substance. The new LC-MS/MS MRM mode method was developed by using Inertsil ODS-3V 150x4.6mm,5µm column as stationary phase. The mobile phase used is the composition of 10Mm Ammonium formate pH3.00buffer:Acetonitrile(9:1)%v/v as mobilephase-A and 10Mm Ammonium formate pH3.00buffer:Acetonitrile(2:8)%v/v as mobile phase-B, isocratic elution of mobile phase-A and Mobile phase-B (60:40)v/v at flow rate of 0.8mL/min.The concentration limits of the both genotoxic impurities were calculated a limit of 37.5ppm based on the concept of TTC (threshold of toxicological concern) and MDD (maximum daily dosage which is 40mg/day for Azilsartan drug substance.The limit of detection(LOD) was found to be 1.4ppm for both Impurity-A and Impurity-B.The limit of quantification(LOQ) for Impurity-A was 4.7ppm and Impurity-B was 4.5ppm respectively The method was found to be linear from 4.7ppm to 78.4ppm for Impurity-A (correlation coefficient:1.000) and 4.5ppm to 75.7ppm for Impurity-B (correlation coefficient:0.999). The method was precise and found percentage of relative standard deviation for six replicate sample preparations of Impurity-A and Impurity-B was below 5.0%. The method accuracy was confirmed based on the recovery studies. Based on the method validation study method was sensitive and selective for quantification both genotoxic impurities.