Separation of regioisomers of metal phthalocyanines

1. A process for the separation of regioisomeric mixtures of metal phthalocyanines of general formula (I)

wherein

Me is selected from the group consisting of Zn, Si(OR 4 ) 2 , Ge(OR 4 ) 2 and AlOR 4 , wherein R 4 is chosen from the group consisting of H and C 1 -C 15 alkyl;

n=0, 1;

R and R 1 are selected from substituents of general formula (II)

wherein

X is selected from the group consisting of O, S, NHCO, —CH 2 —, C═C and C≡C;

Z is selected from phenyl, aryl, arylalkyl and cycloaliphatic groups; and

Y and Y′, equal or different from each other, are selected from C 1 -C 15 alkyl groups;

q=0, 1;

R 2 and R 3 are selected from H and substituents of general formula (II) as defined above, with the proviso that:

at least one of R 2 and R 3 is always other than H; and

when n=0:

a) R 2 and R 3 , same or different from each other, are both different from H, or

b) R 2 =H and R 3 is same or different from R 1 ;

and of pharmaceutically acceptable salts thereof;

said process consisting in a chromatographic separation comprising the following steps:

i) applying the mixture to a separation column containing the stationary phase comprising a solid support;

ii) separating said mixture by eluting the said column with the mobile phase comprising a solvent selected from water, an organic solvent and mixtures thereof, said organic solvent being selected from the group consisting of dichloromethane, tetrahydrofuran, methanol, n-hexane, acetonitrile and mixtures thereof.

2. The process according to claim 1 , wherein the said chromatographic separation is performed by a chromatographic method selected from the group consisting of high pressure liquid chromatography (HPLC) and medium pressure liquid chromatography (MPLC).

3. The process according to claim 2 , wherein the said high pressure liquid chromatography is selected from the group consisting of Normal Phase HPLC, Reverse Phase HPLC and ION PAIR Reverse Phase HPLC.

4. The process according to claim 1 , wherein the said solid support is selected from the group consisting of aluminium oxide, silica and silica on which groups are bonded, said groups being selected from aliphatic groups, aromatic groups and mixtures thereof.

5. The process according to claim 4 , wherein said groups are selected from the group consisting of octyl, octadecyl and equi-molar quantities of phenyl and hexyl groups.

6. The process according to claim 1 , wherein in the said metal phthalocyanines of formula (I) Me is Zn.

7. The process according to claim 1 , wherein in the said metal phthalocyanines of formula (I) n=0, R 2 =H and R 1 =R 3 , X is selected from between O and S, Z is phenyl, and Y and Y′ are selected from between methyl and ethyl.

8. The process according to claim 1 , wherein the said metal phthalocyanine of formula (I) is 1(4),8(11),15(18),22(25)-tetrakis[(3-(dimethylamino)phenoxy) phthalocyaninato] zinc(II) (compound 1).

9. The process according to claim 1 , wherein the said metal phthalocyanine of formula (I) is 1(4),8(11),15(18),22(25)-tetrakis[(4-(dimethylamino)phenoxy) phthalocyaninato] zinc(II) (compound 2).

10. The process according to claim 1 , wherein the said metal phthalocyanine of formula (I) is 1(4),8(11),15(18),22(25)-tetrakis[(2-(dimethylamino)phenoxy) phthalocyaninato] zinc(II) (compound 3).

11. The process according to claim 1 , wherein the said metal phthalocyanine of formula (I) is 1(4),8(11),15(18),22(25)-tetrakis[(4-(diethylamino)phenoxy) phthalocyaninato] zinc(II) (compound 4).

12. The process according to claim 1 , wherein the said metal phthalocyanine of formula (I) is 1(4),8(11),15(18),22(25)-tetrakis[((3-(dimethylamino)phenyl)sulfanyl) phthalocyaninato] zinc(II) (compound 5).

13. The process according to claim 1 , wherein the said metal phthalocyanine of formula (I) is 1(4),8(11),15(18),22(25)-tetrakis[(3-(trimethylammonium)phenoxy) phthalocyaninato] zinc(II) (compound 6).

14. Regioisomers of the metal phthalocyanines of formula (I)

wherein

Me is selected from the group consisting of Zn, Si(OR 4 ) 2 , Ge(OR 4 ) 2 and AlOR 4 , wherein R 4 is chosen from the group consisting of H and C 1 -C 5 alkyl;

n=0, 1;

R and R 1 are selected from substituents of general formula (II)

wherein

X is selected from the group consisting of O, S, NHCO, —CH 2 —, C═C and C≡C;

Z is selected from phenyl, aryl, arylalkyl and cycloaliphatic groups; and

Y and Y′, equal or different from each other, are selected from C 1 -C 15 alkyl groups;

q=0, 1;

R 2 and R 3 are selected from H and substituents of general formula (II) as defined above, with the proviso that:

at least one of R 2 and R 3 is always other than H; and

when n=0:

a) R 2 and R 3 , same or different from each other, are both different from H, or

b) R 2 =H and R 3 is same or different from R 1 ; said regioisomers being in substantially pure form, and represented by:

regioisomer C 4h ;

regioisomer D 2h ;

regioisomer C 2v ;

regioisomer Cs;

mixture of regioisomers C 2v and Cs.

15. Pharmaceutical compositions for the photodynamic therapy comprising a regioisomer of metal phthalocyanines of formula (I) as defined in claim 14 .

16. Diagnostic agents for the in vivo/in vitro diagnostic use containing as the active principle a regioisomer of metal phthalocyanines of formula (I) as defined in claim 14 .