Phthalazinone derivatives

1. A compound of formula (I):

and isomers, salts and solvates thereof, wherein:

A and B together represent an optionally substituted, fused aromatic ring;

X can be NR X or CR X R Y ;

if X=NR X then n is 1 or 2 and if X=CR X R Y then n is 1;

R X is selected from the group consisting of H, optionally substituted C 1-20 alkyl, C 5-20 aryl, C 3-20 heterocyclyl, amido, thioamido, ester, acyl, and sulfonyl groups;

R X is selected from H, hydroxy, amino;

or R X and R Y may together form a spiro-C 3-7 cycloalkyl or heterocyclyl group;

R C1 and R C2 are independently selected from the group consisting of hydrogen and C 1-4 alkyl, or when X is CR X R Y , R C1 , R C2 , R X and R Y , together with the carbon atoms to which they are attached, may form an optionally substituted fused aromatic ring; and

Het is selected from:

where Y 1 is selected from CH and N, Y 2 is selected from CH and N, Y 3 is selected from CH, CF and N, where one or two of Y 1 , Y 2 and Y 3 are N; and

where Q is O or S.

2. A compound according to claim 1 , wherein the fused aromatic ring(s) represented by -A-B- consist of solely carbon ring atoms.

3. A compound according to claim 2 , wherein the fused aromatic ring represented by -A-B- is benzene.

4. A compound according to claim 1 , wherein R C1 and R C2 are hydrogen.

5. A compound according to claim 1 , wherein n is 2, X is NR X , and R X is selected from the group consisting of: H; optionally substituted C 1-20 alkyl; optionally substituted C 5-20 aryl; optionally substituted ester groups; optionally substituted acyl groups; optionally substituted amido groups; optionally substituted thioamido groups; and optionally substituted sulfonyl groups.

6. A compound according to claim 1 , wherein n is 1, X is NR X , and R X is selected from the group consisting of: H; optionally substituted C 1-20 alkyl; optionally substituted C 5-20 aryl; optionally substituted acyl; optionally substituted sulfonyl; optionally substituted amido; and optionally substituted thioamido groups.

7. A compound according to claim 6 , wherein Het is pyridylene and R X is selected from the group consisting of: optionally substituted acyl; optionally substituted sulfonyl; and optionally substituted amido.

8. A compound according to claim 6 , wherein Het is furanylene or thiophenylene and R X is selected from the group consisting of: optionally substituted C 1-20 alkyl; optionally substituted C 5-20 aryl; optionally substituted acyl; optionally substituted sulfonyl; and optionally substituted amido.

9. A compound according to claim 1 , wherein n is 1, X is CR X R Y , R Y is H and R X is selected from the group consisting of: H; optionally substituted C 1-20 alkyl; optionally substituted C 5-20 aryl; optionally substituted C 3-20 heterocyclyl; optionally substituted acyl; optionally substituted amino; optionally substituted amido; and optionally substituted ester groups.

10. A compound according to claim 9 , wherein Het is furanylene or thiophenylene, and R X is selected from optionally substituted amino, wherein the amino groups are selected from H and C 1-20 alkyl or together with the nitrogen atom, form a C 5-20 heterocyclic group.

11. A pharmaceutical composition comprising a compound according to claim 1 and a pharmaceutically acceptable carrier or diluent.

12. A method of treatment of disease ameliorated by the inhibition of PARP, comprising administering to a subject in need of treatment a therapeutically-effective amount of a compound according to claim 1 wherein the disease is selected from the group consisting of septic shock; ischemic injury; reperfusion injury; hemorrhagic shock; and multiple sclerosis.