Highly sensitive method for the determination of genotoxic impurity such as methyl para toluene sulfonate (MPTS) in Levocetirizine drug substance using RP-LC has been presented in the present paper. MPTS were determined by RP-LC method using waters symmetry C18 (250 x 4.6mm), 5µ column as stationary phase. Column temperature maintained 30°C, Injection volume 10µL, flow rare was 1.0 ml/min, sample cooler temperature 5°C and run time was 35mintues. pH 2.50 phosphate buffer was used as mobile phase-A and acetonitrile and water in the ratio of 90:10 %v/v was used as mobile phase-B. The method validation has been carried as per International Conference on Harmonization guidelines (ICH). Limit of quantitation (LOQ) was found 64.446 μg/ mL for MPTS.

Key words: Genotoxic impurity, Levocetirizine, RP-LC method, validation and limit of quantitation.

Abbreviations:

LCZ= Levocetirizine , MPTS=Methyl para toluene sulfonate