title: Determination of the Degradation Chemistry of the Antitumor Agent Pemetrexed Disodium.
abstract: Stress-testing (forced degradation) studies have been conducted on pemetrexed disodium heptahydrate (1) (LY231514·2Na·7H2O) drug substance in order to identify its likely degradation products and establish its degradation pathways. Solid samples of the drug substance were stressed under various conditions of heat, humidity, and light, and solutions of the drug substance were stressed under various conditions of heat, light, oxidation, and over a wide pH range (1-13). The stressed samples were analyzed using a gradient elution reversed-phase HPLC method. The 7 major degradation products detected in the stress-testing studies were isolated, and the structures were elucidated via spectroscopic characterization. The structures of the degradation products and their proposed mechanisms of formation indicate that 1 degrades via 2 main pathways: oxidation and hydrolysis. Of the 7 identified degradation products, 6 are proposed to result from oxidation and 1 from hydrolysis.
authors.affiliation: Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285. Electronic address: patjansen@lilly.com.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Jansen
authors.affiliation: Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285.
authors.forename: William K
authors.initials: WK
authors.lastname: Smith
authors.affiliation: Baertschi Consulting, Carmel, Indiana 46033.
authors.forename: Steven W
authors.initials: SW
authors.lastname: Baertschi
authors.affiliation: Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285.
authors.forename: Douglas E
authors.initials: DE
authors.lastname: Dorman
authors.affiliation: Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285.
authors.forename: Craig A J
authors.initials: CAJ
authors.lastname: Kemp
authors.affiliation: Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285.
authors.forename: Karen A
authors.initials: KA
authors.lastname: McCune
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry* / Q000378:metabolism; D004355:Drug Stability; D006358:Hot Temperature / Q000009:adverse effects*; D006813:Humidity / Q000009:adverse effects*; D008027:Light / Q000009:adverse effects*; D000068437:Pemetrexed / Q000737:chemistry* / Q000378:metabolism; D010782:Photolysis
chemical_list: D000970:Antineoplastic Agents; D000068437:Pemetrexed
keywords: LC-MS; chemical stability; degradation products; oxidation; photodegradation; stability