Validation of Stability Indicating UPLC Method for Quantification of Lumateperone Impurities and Structural Characterization of Stress Degradation products of Lumateperone by UPLC-MS/MS

In this study a simple analytical approach integrating UPLC and mass spectrometry for resolution, identification and structural characterization of stress degradation products (DPs) of Lumateperone. Lumateperone pure drug was exposed to oxidative, hydrolytic, thermal, and photolytic stresses conditions that produce 7 DPs. The formed DPs along with known nitroso impurities of Lumateperone were resolved on Waters Acquity (100 mm) UPLC® HSS C18 column employing with 15 mM ammonium acetate, methanol and acetonitrile in 45:25:30 (v/v) at pH 4.3 as mobile phase in isocratic mode with 238 nm through UPLC. The method was validated with 10.5–63 µg/mL for Lumateperone and 0.105-0.63 µg/mL for impurities with acceptable recovery and reproducibility. Elucidation of these DPs was achieved by scrutinizing their fragmentation pattern and masses discerned through LC–MS/MS and MSn analysis. These unidentified DPs were ascertained to be (1-(4-fluorophenyl)-4-(3-methyl-2,3,6b,7,10,10a-hexahydro-1H-pyrido[3',4':4,5] py-rrolo[1,2,3-de]quinoxalin-8(9H)-yl)butan-1-ol) (DP 1), (1-(4-fluorophenyl) butan-1-one) (DP 2), (1-(4-fluorop-henyl)-4-((3-(4-methyl-3,4-dihydroquinoxalin-1(2H)-yl)propyl)(vinyl)amino) butan-1-ol) (DP 3), (2,3,6b,7,8,9, 10,10 a-octahydro-1H-pyrido[3',4':4,5]pyrrolo[1,2,3-de]quinoxaline) (DP 4), (3-methyl-2,3,6b,7, 10,10a hexah-ydro-1H-pyrido[3',4':4,5]pyrrolo[1,2,3-de]quinoxaline) (DP 5), (1-(4-fluoro phenyl)-4-(3-methylpiperidin-1-yl) butan-1-one) (DP 6) and (4-(3-methyl-2,3,6b,7,10, 10a-hexahydro-1H-pyrido [3',4':4,5] pyrrolo[1,2,3de] quino-xalin-8(9H)-yl)-1-phenylbutan-1-one) (DP 7). The proposed analytical method was validated and permissible results were achieved. The results suggest that the method was appropriate for quantifying nitroso impurities of Lumateperone along with structural characterization and quantification of DPs of Lumateperone.