Accumulation of zinc-phthalocyanine (Zn-Pc) in the aorta of atherosclerotic rabbits

Phthalocyanines are structural analogs of porphyrins and are characterized by a closely similar mechanism of transport in the bloodstream. We evaluated the accumulation of liposomebound Zn(II)-phthalocyanine (Zn-Pc) by atherosclerotic aortas in rabbits. The biodistribution of intravenously injected Zn-Pc (0.023 mg/kg body weight) in the serum and some tissues resembled that previously observed for other experimental animals. Moreover, significant amounts of Zn-Pc were recovered from the aorta of the atherosclerotic and not of the normal rabbits. The maximum accumulation (circa 0.04g of Zn-Pc g^–1 tissue) was observed at 3 h after injection. We conclude that Zn-Pc might act as a fluorescence marker for atheromas and it has a potential as a phototherapeutic agent in atherosclerosis.This topic was presented at the International Conference on Photodynamic Therapy and Medical Laser Applications, held in London on July 19–21, 1988.