Last week we said we would look and see what we had on this topic.  Of the articles we found, the one most on point was:

J. Roberts, "Phototoxicity and cytotoxicity of fullerol in human lens epithelial cells," Toxicology and Applied Pharmacology, Vol. 228, at 49-58 (2008).

The article reports on a study of the ocular toxicity of hydroxylated fullerenes which "determined that fullerols are both cytotoxic and phototoxic to human lens epithelial cell model system in the presence of either UVA or visible light." The researcher exposed human lens cells and whole rat eye lenses to a fullerol suspension for 24 and 1 hour periods, both in the dark and in visible light. Both the human lens cell and the rat lenses absorbed some of the fullerene solution.  The author reports that "fullerol exhibits both dark cytoxicity and phototoxic effects on human lens epithelial cells."   This could theoretically cause a loss of lens transparency, leading to cataracts.   The study concludes that "before fullerols are used in the future to deliver drugs to the eye, their potential side effects on the human eye should be further examined."

Other articles we found were:

A. de Compos, et al., "Chitosan nanoparticles as new ocular drug delivery systems: in vitro stability, in vivo fate, and cellular toxicity," Pharmaceutical Research, Vol. 21, No. 5 (May 2004).  ("No inherent toxicity can be attributed to the [Chitosan] nanoparticles at concentrations as high as 2mg/ml. In addition, the viability of the recovered cells was totally preserved irrespective of the nanoparticles concentration.");

M. Alonso, et al., "The potential of Chitosan in Ocular Drug Delivery," Journal of Pharmacy and Pharmacology, Vol. 55, at 1451-1563 (2003).  ("Preliminary studies performed in conjunctival cell cultures have shown the low toxicity of Chitosan nanoparticles.");

B. Short, "Safety Evaluation of Ocular Drug Delivery Formulations," Techniques and Practical Considerations, Toxicology Pathology, Vol. 36, at 49-62 (2008);

Y. Diebold, et al., "Ocular drug delivery by liposome-chitosan nanoparticles complexes (LCS-NP)," Biomaterials, Vol. 28, at 1553-1564 (2007);

J. Bourges, et al., "Ocular Drug Delivery Targeting the Retina and Retinal Pigment Epithelium Using Polyactide Nanoparticles," Investigative Ophthalmology & Visual Science, Vol. 44, No. 8 (2003); and

R. Bejjani, et al., "Nanoparticles for gene delivery to retinal pigment epithelial cells," Molecular Vision, Vol. 11 at 124-132 (2005);