Identification and characterization of forced degradation products of pralatrexate injection by LC-PDA and LC-MS

Pralatrexate (PTXT) is an antineoplastic folate analog and the chemical name is (2S)-2-[[4-[(1RS)-1-[(2,4-diaminopteridin-6-yl)methyl]but-3-ynyl] benzoyl] amino] pentanedioic acid. Degradation products of PTXT drug product (DP) under different forced degradation conditions have been studied using LC-PDA and LC-MS techniques. PTXT DP was subjected to forced degradation under the conditions of hydrolysis, photolysis, oxidation, and heat in accordance with ICH guidelines. The LC-MS compatible HPLC method was developed and stressed solutions were chromatographed on reversed phase HPLC. The degradation products were monitored at a wavelength of 242nm. Stress study revealed that PTXT was sensitive towards acid, alkali, peroxide, light and heat. The degradation impurities (I-IX) were identified and characterized using LC-PDA and mass spectral data.