Cellular uptake and photosensitizing properties of hematoporphyrin di-ethers with similar chromatographic properties as the tumorlocalizing fraction of hematoporphyrin derivative.

The di-methyl-, di-ethyl-, di-propyl-, di-normal butyl-, and di-iso-butyl-ethers of hematoporphyrin were synthesized and shown to possess chromatographic properties similar to those of the tumorlocalizing components of hematoporphyrin derivative (Hpd). The cellular uptake of these ethers, as well as their retention in cells during incubation with porphyrin free medium, increased with decreasing polarity and so did their efficiency in sensitizing cultured cells to photoinactivation. The least polar of the porphyrin ethers tested showed up to a 10-fold stronger efficiency in sensitizing cultured cells to photoinactivation than Hpd and Photofrin II (P II).