Ultra‐High‐Performance Liquid Chromatography Combined With Mass Spectrometry Detection Analytical Method for the Determination of <i>N</i>‐Nitrosoduloxetine in Duloxetine HCl

In the present study, one simple, fast, feasible, and sensitive ultra-high-performance liquid chromatography combined with mass spectrometry detection method, using electrospray ionization, is proposed. This method was developed and validated for the determination of N-nitrosoduloxetine content in Duloxetine HCl active pharmaceutical ingredient in 11 min employing a simple preparation method for both reference and sample solutions. The proposed method was validated as per regulatory guidelines. Acquity HSS T3 (3.0 × 100 mm, 1.8 μm) column and formic acid 0.1% in water combined with acetonitrile were used for chromatographic separation. The limit of detection and the limit of quantification-reporting threshold-were found to be 0.7 and 70 ppb, respectively. The trueness and precision of the method have been demonstrated in the working range, giving values of recovery within the range of 100%-110%, and the regression coefficients (R) were found to be in the range of 0.9990-0.9991. This method could be used for controlling N-nitrosoduloxetine content in duloxetine HCl drug substance batches manufactured at Moehs group.