Abstract: The present invention relates to pharmaceutically active ornithine compounds, particularly to pharmaceutically acceptable ammonium salts of N?-acyl derivatives of N?(4-amino-4-deoxypteroyl)-L-ornithine compounds; and methods of treatment and pharmaceutical compositions that utilize or comprise one or more of such ammonium salts. The ammonium salts provided by the invention exhibit superior chemical stability than corresponding acidic N?-acyl derivatives of N?-acyl derivatives of N?(4-amino-4-deoxypteroyl)-L-ornithine compounds.

Abstract: The present invention relates to pharmaceutically active ornithine compounds, particularly to pharmaceutically acceptable ammonium salts of N?-acyl derivatives of N?(4-amino-4-deoxypteroyl)-L-ornithine compounds; and methods of treatment and pharmaceutical compositions that utilize or comprise one or more of such ammonium salts. The ammonium salts provided by the invention exhibit superior chemical stability than corresponding acidic N?-acyl derivatives of N?-acyl derivatives of N?(4-amino-4-deoxypteroyl)-L-ornithine compounds.

Abstract: In one embodiment, the present invention relates to a new class of ammonium salts of N?-acyl derivatives of N?-(4-amino-4-deoxypteroyl)-L-ornithine compounds having a structure according to formula II-IV. Formula II has the structure of: wherein: R2 represents up to four groups independently selected at each occurrence of R2 from the group consisting of hydrogen, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, C3-8 cycloalkyl, C1-6 alkoxy, chloro, fluoro, hydroxy, and —COOH; R3, R4, and R5 are each independently selected from hydrogen and C1-6 alkyl; or NR3R4 taken combination can form a 5 to 7 member heterocycle having at least one nitrogen ring atom; and x is a real number greater than 0 and less than about 4. The ammonium salts provided by the invention exhibit high inhibitory activity against the growth o methotrexate-resistant cells, and also exhibit superior chemical stability than corresponding acidic N?-acyl derivatives of N?-acyl derivatives of N?(4-amino-4-deoxypteroyl)-L-ornithine compounds.