Abstract: The present invention provides stable crystalline polymorphic forms of antifolate compounds, particularly (S)-2-{4-[2-(2,4-diamino-quinazolin-6-yl)-ethyl]-benzoylamino}-4-methylene-pentanedioic acid, dipotassium salt, and methods of preparation thereof The polymorphs may be in the form of hydrates. The invention further provides pharmaceutical compositions comprising the polymorphs and methods of treatment using the polymorphs. The polymorphs are useful in the treatment of multiple conditions, including abnormal cell proliferation, inflammatory diseases, asthma, and arthritis, and the polymorphs may be administered alone in or combination with on or more further active agents.

Abstract: The present invention provides methods of preparing antifolate compounds. The inventive methods can particularly be use for preparing compounds exhibiting improved bioavailability, making the compound particularly useful in pharmaceutical compositions. The compounds prepared according to the inventive methods are useful in the treatment of multiple conditions, including abnormal cell proliferation, inflammatory diseases, asthma, and arthritis.