A simple and reliable head space gas chromatographic method has been developed for the determination of residual Chloromethane, Chloroethane and 2-Chloropropane in Pregabalin  drug substance. The proposed method is based on flame ionization detection technique with DB-624 as stationary phase and passing nitrogen carrier gas. The performance of the method was assessed by evaluating the specificity, linearity, sensitivity, precision and accuracy experiments. The established limit of detection and limit of quantification values for the Chloromethane, Chloroethane and 2-Chloropropane was in the range of 41.37 and 125.18 µg/mL , 41.61 and 126.09 µg/mL and 41.55 and 125.78 µg/mL.  The correlation coefficient value of the linearity experiment was 0.9999, 0.9999 and 0.9999. The average recoveries for the accuracy were in the range of 92.8-99.9%. The results proved that the method is suitable for the determination of Chloromethane, Chloroethane and 2-Chloropropane content in Pregabalin drug substance.

Key Words: Chloromethane, Chloroethane and 2-Chloropropane, Genotoxic impurities, Pregabalin  Drug Substance, ICH guidelines, Validation.