Porphyrin Carrier Molecules Porphyrins are actively taken up and retained by cancer cells. SLIL scientists recognized the potential to bind cytotoxic drugs to porphyrin molecules and use them to gain access to cancer cells, especially solid tumors. This potentially allows for the active uptake and accumulation of the cytotoxic drug within cancer cells. This would not only enhance the effectiveness of the drug but might also reduce the otherwise toxic side-effects often associated with cytotoxic drugs. SLIL has developed several novel compounds based on polyamines bound to porphyrin carriers, and one naphthoquinone-porphyrin compound. To the best of the Company’s knowledge, no other company has used porphyrins as cytotoxic carriers, and a patent was filed by SLIL to cover this technology in 1999. Class Sub-Class Lead Compound Names TTD Porphyrins Porphyrin-naphthoquinone SL11145 Porphyrin-polyamine SL11159 SL11184 SL11211 SL11217 Porphyrin-cyclic polyamine SL11237