Background:We examined the red blood cell and model lipid system membrane effect of some newly synthesized glycosylated tetraphenyl porphyrin derivatives that might be used in photodynamic therapy.
Material/Methods: Red blood cell characteristic hematological parameters were measured, as well as model lipid system phase transition parameters. The results were compared with those of a well known photosensitizer, tetrasulfonated zinc-phthalocyanine.
Results: Our results demonstrate, that neither of the derivatives had an effect in the dark. The effect of applying illumination was strongly dependent on the side chains attached to the porphyrin ring. The phase transition parameters of the model lipid system were influenced similarly.
Conclusions: At least one apolar ring system among the substituents is necessary for the effect. Measurement of hematological parameters seems to be an apparent method for screening photosensitizers toxicity.

Keywords: Neoplasms, therapy, photodynamic, Porphyrins, lipid system