3-[7(R)-Ethyl-2(2)-hexyl-12-[1-(heptyloxy)ethyl]-3,8(R),13,17(S)-tetramethyl-2(1),2(3)-dioxo-2(1),2(2),2(3),7,8,18-hexahydro-17H-pyrido[3,4,5-at]porphyrin-18(S)-yl]propionic acid propyl ester