Photodynamic diagnosis, formulations usable as photosensitizers for this purpose, method for the production and use thereof
In the early detection of cancer, in particular bladder cancer, a photodynamic diagnosis uses, as a photosensitizer, a formulation that contains sodium hypericinate that is bonded to polyvinylpyrrolidone or complexed with polyvinylpyrrolidone.
1. A method for preparing a lyophilizate from which a photosensitizer for photodynamic diagnosis of tumors may be obtained, comprising the following successive steps:
a) preparing a solution of a sodium or potassium salt of hypericin;
b) dissolving a complexing agent selected from the group consisting of polyethylene glycol and poly-N-vinyl amide in the solution;
c) adding sufficient of a buffer system comprising a phosphate buffer or a citric acid buffer to obtain a concentration of 0.0225 mg hypericin/g solution; and
d) lyophilizing the solution to obtain lyophilizate to yield 0.225 mg hypericin in each resulting obtained photosensitizer.
2. The method according to claim 1 , wherein poly-N-vinyl amide is a polyvinylpyrrolidone (PVP) of various degrees of polymerization and cross-linking.