Biodistribution and phototherapeutic properties of Zinc (II) 2,9,16,23-tetrakis (methoxy) phthalocyanine in vivo

E. INÉS YSLAS; CÉSAR PRUCCA; SILVIA ROMANINI; EDGARDO N. DURANTINI; MABEL BERTUZZI; VIVIANA RIVAROLAA

Photodiagnosis Photodynamic Therapy

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2009 vol. 6 p. 62 - 70

1572-1000

Summary Photodynamic therapy (PDT) was investigated using the phthalocyanine photosensitizerZinc (II) 2,9,16,23-tetrakis (methoxy) phthalocyanine (ZnPc(OCH3)4) on BALB/c mice.Animals bearing tumor were treated with 0.2 mg/kg body weight (bw) ZnPc(OCH3)4 and 24 hlater were irradiated with 70, 140 and 210 J/cm2 of visible light from a source delivering39mW/cm2. In this study, we have tested the efficiency of ZnPc(OCH3)4 liposomal formulationon mice. Biodistribution studies were performed in tumor-free mice and tumor-bearingmice at various time points up to 24 h after ZnPc(OCH3)4-PDT treatment. The tumor sizes wereevaluated over different period in parallel experiments. The maximal efficiency and selectivityof photosensitizer accumulation in tumor tissue take place at 24 h after drug administration of0.2 mg/kg bw ZnPc(OCH3)4. In the tumor sections for biochemical studies, apoptosis was visualizedby activation of caspase-3. ZnPc(OCH3)4-PDT tumors showed a significant delay in growthas compared to untreated control mice. In all cases, ZnPc(OCH3)4-PDT-treated tumors showeda significant regression. The results indicated a dramatic decrease of tumors size after 10 dayspost-irradiation with 210 J/cm2 and no recurrence of the disease was detectable within at least90 days. The phototherapeutic agent ZnPc(OCH3)4 demonstrated preferential accumulation intumor in comparison with skin tissues, except in the case of kidney. The ratio of tumor/skintissues ranged a value of 8. These results suggest that ZnPc(OCH3)4-PDT may be of particularimportance in the treatment of accessible malignancies.