Background: Ethionamide (ETA) is widely used as one of the agents for the treatment of
multidrug resistant tuberculosis. Although quality control is an important issue, a fast LC-UV method
for the assay and impurity determination of ETA was lacking. So, the aim of this study was to develop
such a method to evaluate drug products and follow up dissolution tests of ETA tablets.
Methods: Chromatographic separation was achieved using a Hypersil BDS C18 (150 mm×4.6 mm, 3
µm) column kept at 30 °C. The mobile phase consisted of 300 mL of acetonitrile, 0.14 g of NH4H2PO4
and 700 mL of water pumped at a flow rate of 1.0 mL/min. UV detection was performed at 287 nm. The
developed LC method was validated according to the ICH guidelines.
Results: Validation results show that the developed LC method is specific, linear, sensitive, precise,
accurate and robust. Forced degradation studies revealed that the generated degradation products did not
interfere with ETA and known impurities, thus proving the specificity of the developed LC method for
the assay of ETA tablets and quantification of impurities.
Conclusion: A robust, selective, sensitive and fast LC method has been developed and validated for
analysis of ETA and its main impurities in tablets.