TARGETING OF EXPERIMENTALLY-INDUCED ATHEROSCLEROTIC LESIONS BY LIPOSOME-DELIVERED ZN(II)-PHTHALOCYANINE

Zn(Il)-Phthalocyanine (Zn-Pc) is an exogenously administrable dye whic h is accumulated by tumors and other rapidly proliferating tissues. Th is property could be used for visualising atherosclerotic plaques. In order to define the feasibility and the optimal conditions for in vivo labelling of atheroma, we evaluated the ability of Zn-PC to be accumu lated by experimentally induced atherosclerotic lesions in rabbits. We also performed pharmacokinetic investigations to assess photosensitiz er delivery system, difference in phthalocyanine concentration between normal and atherosclerotic vessels, and the time interval after admin istration, which yields a large difference between normal and diseased vessels. We observed a preferential accumulation of Zn-Pc by atherosc lerotic lesions which accumulated about a tenfold larger amount of pho tosensitizer, and the retention of significant amounts for prolonged p eriods. Zn-Pc can be considered as a potentially useful fluorescence m arker for atheroma. The feasibility of photodiagnosis and phototherapy of atheroma deserves further investigation.