Distribution of Xanthene Dyes in DPPC Vesicles: Rationally Accounting for Drug Partitioning Using a Membrane Model

Abstract

The correct selection of a dye that has effective action as a photosensitizer is a primary concern for successful therapeutic outcomes. The effectiveness of the photodynamic agent is related to both the targeting of cell membranes and the photochemical yield of the chosen dye. The distributions of xanthene derivatives Eosin Y, Erythrosin B, and Rose Bengal B in vesicles of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) in both liquid-crystalline and gel phases were investigated by fluorescence spectroscopy. Binding constants, fluorescence anisotropy, fluorescence quenching, fluorescence quantum yield, and fluorescence resonance energy transfer at physiological pH conditions were determined. To Erythrosin B and Eosin Y, the iodide quenching rate constant was shown to involve a sphere of action mechanism driven by a specific interaction between Erythrosin B and Eosin Y molecules and the choline head-group of the phospholipid; in contrast, Rose Bengal B was located deep in the membrane and this mechanism was not present. The dyes can be ordered by their penetration depth in the membrane, and this order was found to be Eosin Y < Erythrosin B < Rose Bengal B. These results demonstrate a rational approach for the screening of more active agents for photodynamic therapy based on the affinity between the xanthene derivatives and DPPC vesicles.

Alkane Chain‐extended Pterin Through a Pendent Carboxylic Acid Acts as Triple Functioning Fluorophore, 1O2 Sensitizer and Membrane Binder

“…As shown in Fig. , the binding constant of CapC to eggPC LUVs was obtained by fitting the fluorescence intensity as a function of the concentration of the LUVs and the value of K b obtained was 8 (± 2) × 10 3 M −1 , which is in the same order of constants obtained for O ‐ and N ‐decyl‐pterins 1 – 4 and other lipophilic compounds . The pterin moiety in CapC has the capacity to form hydrogen bonds with the water phase, even though native pterin is sparingly soluble in water itself.…”

Evidence of photoinduced lipid hydroperoxidation in Langmuir monolayers containing Eosin Y

“…Since the first generation of PS based on tetrapyrrole structure [6][7][8][9], many synthetic compounds such as chlorins, porphyrins, phenothiazines and xanthene derivatives have been proven efficient in PDT [10,11]. Xanthenes, for instance, have shown not only high ΦΔ 1 O 2 but also ability to interact with lipid membranes [12][13][14], which make them attractive as PS.…”

Design of a nanostructured mucoadhesive system containing curcumin for buccal application: from physicochemical to biological aspects

“…where I VH and I VV represent the intensity measured by the excitation of the vertically aligned polarizer and the horizontally aligned polarizer, respectively. G is the instrumental correction factor of the ratio of the sensitivities for vertically and horizontally polarized light [48,88–89].…”