Blood group porphyrins in lipid-protein model systems: Preferential solvation of hematoporphyrin in 1-octanol-N,N-dimethylformamide mixtures

Abstract

109 Natural porphyrins and their analogues play an important role in living nature. They are parts of numerous pharmaceuticals, in particular, they were used to develop agents for photodynamic therapy of cancer [1–3]. The passive transport of photosensitiz ers to cancer cells occurs via the interaction of porphy rins with cell membranes, and the simplest model of the latter is 1 octanol [4]. Furthermore, the environment of the protoporphyrin molecule in a heme consists of amino acid residues, which were modeled by amides, in particular, N,N dimethylformamide (DMF) [5]. Study of the solvation of blood group porphyrins in 1 octanol–DMF mixtures can be used to model the gradual transition from biological object interaction with a slightly polar membrane to the interaction with much more polar protein membrane. To estimate these interactions, which largely determine the passive transport of photosensitizers, we used the enthalpy characteristics of the solutions of hematoporphyrin dimethyl ester–dimethyl ether (H2HPTME) in an 1 octanol–DMF mixture at 298 K.