Characterisation of the photochemotherapeutic agent disulphonated aluminium phthalocyanine and its high-performance liquid chromatographic separated components.

Disulphonated aluminium phthalocyanine (AlPcS2), a potential clinical photosensitiser, has been synthesised in a reproducible form and shown by reversed-phase HPLC to consist of at least eight components which are believed to be individual AlPcS2 regioisomers. These components have been isolated either as single bands or mixtures of two using preparative reversed-phase HPLC methods. The number and position of sulphonate groups per phthalocyanine macromolecule for each component has been determined using a chemical degradation and HPLC assay. Results suggest that the bulk AlPcS2 material consists mostly (> 60%) of an amphiphilic alpha-, alpha-disubstituted regioisomer, with both sulphonate groups substituted to the same side of the molecule (adjacent form). Possible structures for some of the other separated components of AlPcS2 are also presented.