Lutetium texaphyrin (lu-tex): A potential new agent for ocular fundus angiography and photodynamic therapy

PURPOSE: To investigate the suitability of lutetium texaphyrin (lu-tex) as a fluorescence imaging agent in the delineation of retinal vascular and cho roidal vascular diseases. The utilization of an efficient fluorescent molec ule that is also a photosensitizer represents a unique opportunity to coupl e diagnosis and therapy. METHODS: Fundus fluorescence angiography comparing lu-tex (motexafin luteti um, Optrin, Pharmacyclics Inc, Sunnyvale, California) with the conventional angiographic dyes, sodium fluorescein, and indocynanine green (ICG), was p erformed on the eyes of normal and laser-injured New Zealand white rabbits. Plasma pharmacokinetic data and plasma protein binding were assessed in ad dition to light microscopy of the retina in both imaged and laser-injured e yes. RESULTS: Normal retinal and choroidal vasculature was well delineated by lu -tex angiography. Experimentally induced choroidal and retinal vascular les ions were enhanced by lu-tex and demonstrated different staining patterns t han fluorescein or ICG, particularly at the margins of the lesions. Lu-tex cleared rapidly from the plasma, with 39.7% bound to the high-density lipop rotein (HDL) fraction while 15.8% was bound to the low-density lipoprotein (LDL) fraction. No evidence of retinal toxicity after dye administration wa s observed by either ophthalmoscopy and fundus photography or by light micr oscopy, CONCLUSION: Lu-tex angiography is a potentially valuable method for retinal vascular and choroidal vascular evaluation, and it has advantages over flu orescein and ICG angiography. The same agent could conceivably be used for both the identification of abnormal vasculature and subsequent photodynamic treatment. (C) 2000 by Elsevier Science Inc. All rights reserved.