Determination of potential nitrosamines NDMA, NDIPA and N-Nitroso Duloxetine in Duloxetine Hydrochloride by LC-MS/MS using APCI source

A sensitive, simple, rapid and robust LC-MS/MS method was developed for the determination of potential nitrosamines NDMA, NDIPA and N -Nitroso Duloxetine in Duloxetine Hydrochloride by using APCI-MS/MS Technic. The study was performed with gradient elution. (Time/ % Mobile Phase B: 0/10,5/10,10/90,16/90,16.1/10,20/10). The mobile phase consists of a mixture of formic acid and methanol. The buffer was degassed before running at a flow rate of 0.5 mL/ min. The column temperature was at 40 °C. The 50 µL volume of sample was injected per run and peaks were detected using DAD detector. The LC-APCI/MS/MS studies were carried out on Ultivo Triple Quadrupole LC/MS/MS (Agilent, USA) G6470A mass spectrometer, ion source voltage 4000 V, de clustering potential 40 V, entrance potential 10 V, with the nebulizer gas as nitrogen at 25 psi. The LC part consists of Agilent 1260 Infinity-II series HPLC system with binary gradient pump with a degasser and an auto sampler. X-Bridge ® Phenyl C18, 100 × 4.6 mm, 3.5 µm particle size was used for chromatographic separation. Three nitrosamine impurities were ionized and quantified in positive mode of atmospheric pressure chemical ionization (APCI) using multiple reaction monitoring (MRM). As per ICH guidelines, method validation was performed and evaluated. The limit of quantification and detection was found to give good S/N ratios with good linearity range of 0.003–0.045 ppm with regression coefficient > 0.999 for all the three nitrosamine impurities. Method recoveries are also established using three-step sample preparation and are found to be satisfactory within 80 %−120 %. This method can be successfully applied for the determination of potential nitrosamine impurities in Duloxetine Hydrochloride for routine analysis and stability assessment.