An improved ion chromatographic method for fast and sensitive determination of N-methylpyrrolidine in cefepime hydrochloride.

An alternative ion chromatographic method to the existing USP method for the determination of N-methylpyrrolidine (NMP) in cefepime hydrochloride is developed. The cefepime in solution behaves as a strong cation and gets retained in the analytical column, leading to reduction in column capacity and irreproducible retention time. The retained drug has to be removed with a special rinsing solution, followed by re-equilibration with the mobile phase. This process takes at least 3 to 4 h time for sample analysis. We used a silica-based cation exchange column with poly-butadiene-maleic acid functional group attached with an optimized mobile phase composition. The characteristic feature of this method is the short analysis time with a clear separation of NMP and the cationic drug molecule within a run-time of 30 min. The developed method overcomes the limitations of the USP method. This method describes the matrix elimination by choosing appropriate column and eluent condition. The method is tested for selectivity, linearity, limits of detection and quantification, accuracy, and precision and is suitable for continuous sample analysis.