Neutrexin is the brand name for trimetrexate glucuronate. Trimetrexate, a 2,4-diaminoquinazoline, non-classical folate antagonist, is a synthetic inhibitor of the enzyme dihydrofolate reductase (DHFR). Neutrexin (trimetrexate glucuronate inj) is available as a sterile lyophilized powder, containing trimetrexate glucuronate equivalent to either 200mg or 25mg of trimetrexate without any preservatives or excipients. The powder is reconstituted prior to intravenous infusion (see DOSAGE AND ADMINISTRATION, Reconstitution And Dilution).

Trimetrexate glucuronate is chemically known as 2,4-diamino-5-methyl-6-[(3,4,5-trimethoxyanilino)methyl] quinazoline mono-D-glucuronate, and has the following structure:

The empirical formula for trimetrexate glucuronate is C₁₉H₂₃N₅O₃•C₆H₁₀O₇ with a molecular weight of 563.56. The active ingredient, trimetrexate free base, has an empirical formula of C₁₉H₂₃N₅O₃ with a molecular weight of 369.42. Trimetrexate glucuronate for injection is a pale greenish-yellow powder or cake. Trimetrexate glucuronate is soluble in water ( > 50 mg/mL), whereas trimetrexate free base is practically insoluble in water ( < 0.1 mg/mL). The pKa of trimetrexate free base in 50% methanol/water is 8.0. The logarithm10 of the partition coefficient of trimetrexate free base between octanol and water is 1.63.

Last reviewed on RxList: 4/20/2009
This monograph has been modified to include the generic and brand name in many instances.