Development of a Validated RP-HPLC Method for Estimation of Ethionamide in Spiked Human Plasma with UV Detection

A simple, rapid and economic RP-HPLC method was developed and validated for estimation of Ethionamide in spiked human plasma. The drug along with Guaifenesin (used as internal standard) was extracted from plasma by liquid-liquid extraction (LLE) procedure using ethyl acetate as organic solvent. The drug was well resolved from the plasma interference and internal standard in a reversed phase mode on C 18 (250 × 4.6 mm, 5 μ) column with methanol: water (40: 60 %, v/v) as mobile phase, at a flow rate of 1 mL/min. The detection was performed at 275 nm. The developed method was validated as per the US-FDA guidelines, where the weighted linear regression was used in calibration experiments to obtain the homoscedasticity. In accuracy and precision studies, intra-day and inter-day, % relative error was found between ± 15 and % RSD was less than 15 %. Stability experiments indicated that the drug remained stable after three freeze-thaw cycles.