RESUMO
Microencapsulation and targeted delivery of cytotoxic and antibacterial agents of photodynamic therapy (PDT) improve the treatment outcomes for infectious diseases and cancer. In many cases, the loss of activity, poor encapsulation efficiency, and inadequate drug dosing hamper the success of this strategy. Therefore, the development of novel and reliable microencapsulated drug formulations granting high efficacy is of paramount importance. Here we report the in vitro delivery of a water-soluble cationic PDT drug, zinc phthalocyanine choline derivative (Cholosens), by biodegradable microcapsules assembled from dextran sulfate (DS) and poly-l-arginine (PArg). A photosensitizer was loaded in pre-formed [DS/PArg]4 hollow microcapsules with or without exposure to heat. Loading efficacy and drug release were quantitatively studied depending on the capsule concentration to emphasize the interactions between the DS/PArg multilayer network and Cholosens. The loading data were used to determine the dosage for heated and intact capsules to measure their PDT activity in vitro. The capsules were tested using human cervical adenocarcinoma (HeLa) and normal human dermal fibroblast (NHDF) cell lines, and two bacterial strains, Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. Our results provide compelling evidence that encapsulated forms of Cholosens are efficient as PDT drugs for both eukaryotic cells and bacteria at specified capsule-to-cell ratios.
RESUMO
An unprecedented stable neutral radical nickel(II) complex of 3,5-bis(dimedonyl)azadiisoindomethene (1) was prepared by the direct reaction between 1,3-diiminoisoindoline and dimedone. A new radical complex 1 has an intense and narrow absorption at 1008 nm and can be reduced to a less stable anionic [1]- with a typical aza(dibenzo)boron dipyrromethene (aza-BODIPY) UV-vis spectrum. Complex 1, along with two other colored condensation reaction products 2 and 3, was characterized by spectroscopy and X-ray crystallography, while the paramagnetic nature of 1 was probed by EPR and SQUID methods. Complex 1 forms dimers in the solid state with short (â¼3.16 Å) Ni---Ni contacts. Redox data on 1 are indicative of a reversible reduction process in this complex; its magnetism suggests a S = 1/2 state with the spin density delocalized over the aza-BODIPY core. The experimental data 1 and [1]- were correlated with the density functional theory (DFT) and time-dependent DFT calculations.
RESUMO
Physico-chemical properties, biodistribution in animal tissues, and PDT efficacy of bacteriochlorin photosensitizers, namely cationic salts of synthetic meso-tetrakis(N-alkyl-3-pyridyl)bacteriochlorins were studied in ÐÐÑ2 cell line and in the LLC mouse model. The tested compounds showed high stability in the dark and high in vitro phototoxicity against ÐÐÑ2 cells (the half maximal inhibitory concentration LD50 in the range from 0.34±0.03 to 1.5±0.03µm). Synthetic bacteriochlorins rapidly accumulate in mouse tumor tissue with tumor-to-normal tissue fluorescence contrast ratios of 2.3-3.3, possess high PDT activity against LLC cells: inhibition of tumor growth, TGI 85.8-100%, increase in life span, ILS 105.7-129.2%, response rate, RR 50-100%. The highest PDT efficacy was found for meso-tetrakis[1-(4'-bromobutyl)-3-pyridyl]bacteriochlorin tetrabromide (IC50 0.34±0.03µm in vitro, TGI and RR 100% in vivo).
Assuntos
Carcinoma Pulmonar de Lewis/tratamento farmacológico , Fotoquimioterapia , Fármacos Fotossensibilizantes/uso terapêutico , Porfirinas/uso terapêutico , Animais , Carcinoma Pulmonar de Lewis/patologia , Feminino , Camundongos , Fármacos Fotossensibilizantes/química , Porfirinas/química , Sais , Carga Tumoral/efeitos dos fármacosRESUMO
In photodynamic therapy (PDT), photosensitizers are required to arrive in high concentrations at selective targets like cancer cells avoiding toxicity in healthy tissue. In this work, we propose the application of porous calcium carbonate carriers in the form of polycrystalline vaterite for this task. We investigated the loading efficiency for the photosensitizer Photosens in vaterite micro- and nanocarriers. A possible release mechanism depending on the surrounding pH was studied, showing a fast degradation of the carriers in buffers below pH7. These results hold out the prospect of a novel PDT drug delivery system. Variation of particle size or additional coatings allow custom-design of workload release curves. An intrinsic cancer-sensitivity can be expected from the pH-dependent release in the acidic microenvironment of cancer tissue.
Assuntos
Antineoplásicos/química , Carbonato de Cálcio/química , Portadores de Fármacos/química , Fármacos Fotossensibilizantes/química , Antineoplásicos/administração & dosagem , Humanos , Concentração de Íons de Hidrogênio , Nanopartículas/química , Neoplasias/tratamento farmacológico , Tamanho da Partícula , Fotoquimioterapia , Fármacos Fotossensibilizantes/administração & dosagemRESUMO
We compare the two-photon absorption (2PA) spectra of non-centrosymmetrical metal-free tribenzo-tetraazachlorin (H2TBTAC) and analogous symmetrical tetra-tert-butyl-phthalocyanine (H2TtBuPc). Surprisingly, despite formal lack of center of inversion, the 2PA spectrum of H2TBTAC displays a two-photon allowed transition at 935 nm, similar to gerade-gerade (g-g) transitions observed in H2TtBuPc and in other symmetrical phthalocyanines. This transition is even better resolved in the singlet-singlet excited-state absorption spectrum. We tentatively explain the survival of the g-g transition in H2TBTAC by assuming that the main π-electron conjugation pathway in the tetraaza-substituted tetrapyrrole macrocycle bypasses the outer parts of the two oppositely located isoindole rings and thus renders the optically responsive core of the chromophore quasi-centrosymmetrical. By using the independently measured ground- and excited-state absorption extinction coefficients, we also show that the two-photon absorptivity can be quantitatively explained by a simple three-level model with the lowest energy Q1 state serving as an intermediate level.
Assuntos
Fótons , Porfirinas/química , Conformação Molecular , Análise EspectralRESUMO
Minor products in the reaction between substituted 1,3-diiminoisoindolines and 2,5-diamino-3,4-dicyanothiophene were identified as the nickel seco-tribenzoporphyrazines 4 and 5, which have been characterized by UV-vis, MCD, NMR, and mass spectroscopy. Experimentally observed tetraazachlorin-type UV-vis spectra of new seco-tribenzoporphyrazines were explained on the basis of DFT and TDDFT calculations.
Assuntos
Níquel/química , Porfirinas/química , Espectroscopia de Ressonância Magnética , Espectrofotometria Ultravioleta , Espectrometria de Massas em TandemRESUMO
Mixed condensation of tetramethylsuccinonitrile and either 2,3-dicyano-5,6-diethylpyrazine, 2,3-dicyanopyridine, or 3,4-pyridinedicarboximide in the presence of nickel chloride forms novel pyrazine-, 2,3-pyridine-, or 3,4-pyridine-ring-fused tetraazachlorin (TAC), tetraazabacteriochlorin (TABC), and tetraazaisobacteriochlorin (TAiBC) derivatives. All possible structural isomers were separated using repeated thin-layer chromatography and have been investigated by absorption and magnetic circular dichroism spectroscopy. Similarly to previously reported TAC analogues, the TAC and TABC derivatives show large splitting of the Q band, while a single, intense absorption band is observed for the TAiBC derivatives. Although the absorption spectra are practically identical in shape for the separated structural isomers of TACs and TABCs, the Q-band maxima of the TAiBCs depend significantly on their structures. The observed spectroscopic properties were interpreted on the basis of electrochemical data and the results of (time-dependent) DFT calculations.
Assuntos
Compostos Aza/química , Porfirinas/química , Pirazinas/química , Piridinas/química , Absorção , Dicroísmo Circular , Eletroquímica , Isomerismo , Espectroscopia de Ressonância Magnética , Magnetismo , Nitrogênio/química , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/isolamento & purificação , Porfirinas/isolamento & purificação , Teoria Quântica , Espectrofotometria Ultravioleta , Fatores de TempoRESUMO
In 1992-2006 at P.A. Hertsen Moscow Oncology Research Institute photodynamic therapy (PDT) was performed in 48 esophageal cancer patients (total 48 lesions). For PDT we used Russian photosensitizers (Photogem, Photosens, Radachlorin, Alasens), Russian diode lasers (Crystall) and endoscopic equipment. As a result of PDT complete regression was in 77% of esophageal cancer lesions, partial regression was in 23%. The follow-up period was 3-11 years. Median of survival was in 4.59 years of esophageal cancer patient.
Assuntos
Neoplasias Esofágicas/tratamento farmacológico , Fotoquimioterapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do TratamentoRESUMO
N-(Porphyrin-2-ylmethyl)glycine was synthesized and used as precursor of azomethine ylide, which was trapped with several dipolarophiles. The reaction of that azomethine ylide with dimethyl fumarate afforded the expected adduct. However, with 1,4-benzo- and 1,4-naphthoquinones only dehydrogenated adducts were isolated. Also, the reaction of that ylide with meso-tetrakis(pentafluorophenyl)porphyrin and tetraazaporphine allowed access to novel porphyrin-chlorin and porphyrin-tetraazachlorin dyads.