Analogs of biologically active, naturally occurring polyamines, pharmaceutical compositions and methods of treatment

A polyamine having the formula:

• or a salt thereof with a pharmaceutically acceptable acid wherein:
• R21-R6 may be the same or different and are alkyl, aryl, aryl alkyl, cycloalkyl, optionally having an alkyl chain interrupted by at least one etheric oxygen atom, or hydrogen and at least one of said R1 and R2 and at least one of said R5 and R6 are not hydrogen;
• N1, N2, N3 and N4 are nitrogen atoms capable of protonation at physiological pH's;
• a and b may be the same or different and are integers from 1 to 4;
• A, B and C may be the same or different and are bridging groups selected from the group consisting essentially of alkylene, branched alkylene, cycloalkylene, arlalkylene or unsubstituted heterocyclic bridging groups, which effectively maintain the distance between said nitrogen atoms such that said polyamine:
• (i) is capable of uptake by a target cell upon administration of said polyamine to a human or non-human animal;
• and
• (ii) upon uptake by said target cell, competitively binds via an electrostatic interaction between the positively charged nitrogen atoms to substantially the same biological counter-anions as the intracellular natural polyamines in the target cell, provided that where A, B or C is a heterocyclic bridging group, the bridging group is an unsubstituted heterocyclic group incorporating said N′, N2, N3or N4 atoms the heterocyclic ring as an unsubstituted N atom;
• excepting the polyamines of the above formula wherein:
• (a) A, B and C are each tetramethylene, and R1-R6 are each methyl:
• (b) A and C are both trimethylene, B is tetramethylene, R1 and R6 are both ethyl, and R2-R5 are each H,
• (c) A and C are both trimethylene, B is tetramethylene, and R1-R6, are each methyl;
• (d) A. B and C are each trimethylene, and R1-R6 are each methyl,
• (e) A. B and C are each trimethylene, R1 and R6 are both ethyl, R2 and R5 are both H, and R3 and R4 are both methyl;
• (f) A and C are both trimethylene, B is tetramethylene, and R1-R6 are the same and are either methyl, ethyl or propyl;
• (g) A, B and C are each dimethylene:
• R1, R3 and R6 are each H, R2 is benzyl, R4 and R5 are both methyl;
• (h) B is heptamethylene;
• and
• (i) A, B and C are each tetramethylene, R1 and R6 are both ethyl, and R2-R5 are each H;
• said polyamine, upon binding to said biological counter-anion in the cell, functions in a manner biologically different than said intracellular polyamines, said polyamine not occurring in nature.