Interaction of aggregates, oligomers, and monomers of therapeutic active hematoporphyrin derivatives with membranes and membrane-like structures

The interaction of the therapeutic active haematoporphyrin derivatives (HpD, Photosan) with micelles, liposomes, erythrocyte ghosts and erythrocytes has been investigated by fluorescence and difference absorption spectroscopy. HpD samples of different preparations were used and exhibit similar interaction patterns with membranes. The results obtained show that the monomers and/or aggregates from the aqueous phase, which are in equilibrium with the monomers, are taken up by the membranes to a much lesser extent than chemically bound oligomers and self associated oligomer complexes. Oligomers are taken up and defolded, leading to an increasing amount of monomers in the membrane versus incubation time. The photodynamic activity during the incubation process was measured to be proportional to the fluorescence of the membrane associated monomers.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.