Pemetrexed is a folate analog metabolic inhibitor. The drug substance, pemetrexed ditromethamine, has the chemical name L-glutamic acid, N-[4-[2-(2-amino-4,7-dihydro-4-oxo-1H-pyrrolo[2,3-d] pyrimidin-5-yl)ethyl]benzoyl]-, ditromethamine dihydrate with a molecular formula of C28H47N7O14 and a molecular weight of 705.68. The structural formula is as follows:
Pemetrexed for Injection is a sterile white-to-light yellow or green-yellow lyophilized powder in single-dose vials to be reconstituted for intravenous infusion. Each 100-mg vial of Pemetrexed for Injection contains 100 mg pemetrexed (equivalent to 157 mg pemetrexed ditromethamine) and 106 mg mannitol. Each 500-mg vial of Pemetrexed for Injection contains 500 mg pemetrexed (equivalent to 783 mg pemetrexed ditromethamine) and 500 mg mannitol. Each 1-gram vial of Pemetrexed for Injection contains 1 gram pemetrexed (equivalent to 1.57 gram pemetrexed ditromethamine) and 1 gram mannitol.