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Jonathan L. Sessler - One of the best experts on this subject based on the ideXlab platform.
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rapid insertion of bismuth radioactive isotopes into Texaphyrin in aqueous media
Journal of Porphyrins and Phthalocyanines, 2017Co-Authors: Gregory Thiabaud, Valery Radchenko, Justin J Wilson, Kevin D John, Eva R Birnbaum, Jonathan L. SesslerAbstract:Radioisotopes 213Bi and 207Bi were successfully inserted into a water-soluble and tumor-targeting Texaphyrin ligand. The reaction with 207Bi(OAc)3 proceeds in about 15 min in aqueous media without the use of any organic base. The Bi(III) Texaphyrin complex formed (3) is stable in aqueous media even in the presence of an excess of competitive chelators (EDTA or citric acid), as well as in human blood plasma. These results validate Texaphyrins as potential candidates for coordinating bismuth radionuclides and set the stage for their use in targeted alpha therapy (TAT).
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liposomal Texaphyrin theranostics for metastatic liver cancer
Journal of the American Chemical Society, 2016Co-Authors: Min Jung Chang, Kwan Soo Hong, Sunyoung Park, Jonathan L. SesslerAbstract:Reported here is a new theranostic agent, 1, which consists of a Gd3+-Texaphyrin core conjugated to a doxorubicin prodrug via a disulfide bond. Conjugate 1 was designed to undergo cleavage in the presence of glutathione (GSH), a species typically upregulated in cancer cells. As prepared, conjugate 1 displays no appreciable fluorescence. However, when exposed to excess GSH an increase in the fluorescence intensity at 592 nm is observed that is ascribed to release of free doxorubicin. To improve the solubility and enhance the tumor targeting of 1, it was loaded into folate-receptor-targeted liposomes to produce FL-1 (for folate liposome loaded with 1). As inferred from both fluorescence turn on studies and independent HPLC analyses, FL-1 was found to undergo selective uptake and cleavage to release free Dox in the KB and CT26 cell lines, which express folate receptors on the cell surface, relative to the HepG2 and NIH3T3 cell lines, which show low expression of those receptors. FL-1 was found to produce a g...
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acid triggered release of doxorubicin from a hydrazone linked gd3 Texaphyrin conjugate
Chemical Communications, 2016Co-Authors: Min Hee Lee, Eun Joong Kim, Hyunseung Lee, Sunyoung Park, Kwan Soo Hong, Jong Seung Kim, Jonathan L. SesslerAbstract:The hydrazone-based Gd(3+)-Texaphyrin doxorubicin conjugate 1, releases active doxorubicin at acidic pH values, allowing its components to be followed by two complementary imaging methods, namely Off-On fluorescence enhancement and MR imaging. It thus acts as a promising theranostic agent.
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Liposomal Texaphyrin Theranostics for Metastatic Liver Cancer
2016Co-Authors: Min Hee Lee, Eun Joong Kim, Hyunseung Lee, Sunyoung Park, Kwan Soo Hong, Jong Seung Kim, Min Jung Chang, Hyun Min Kim, Jonathan L. SesslerAbstract:Reported here is a new theranostic agent, 1, which consists of a Gd3+-Texaphyrin core conjugated to a doxorubicin prodrug via a disulfide bond. Conjugate 1 was designed to undergo cleavage in the presence of glutathione (GSH), a species typically upregulated in cancer cells. As prepared, conjugate 1 displays no appreciable fluorescence. However, when exposed to excess GSH an increase in the fluorescence intensity at 592 nm is observed that is ascribed to release of free doxorubicin. To improve the solubility and enhance the tumor targeting of 1, it was loaded into folate-receptor-targeted liposomes to produce FL-1 (for folate liposome loaded with 1). As inferred from both fluorescence turn on studies and independent HPLC analyses, FL-1 was found to undergo selective uptake and cleavage to release free Dox in the KB and CT26 cell lines, which express folate receptors on the cell surface, relative to the HepG2 and NIH3T3 cell lines, which show low expression of those receptors. FL-1 was found to produce a greater antiproliferative effect in the case of the KB and CT26 cell lines as compared to that in the HepG2 and NIH3T3 cell lines. FL-1 was also found to provide enhanced magnetic resonance imaging in vivo under conditions of T1 contrast in the early stage of metastatic cancer progression. Finally, time-dependent tumor regrowth studies involving both subcutaneous and metastatic liver cancer mouse models revealed that FL-1 is capable of reducing the tumor burden in vivo
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photoinduced reduction of ptiv within an anti proliferative ptiv Texaphyrin conjugate
Chemistry: A European Journal, 2014Co-Authors: Gregory Thiabaud, Jonathan F. Arambula, Zahid H. Siddik, Jonathan L. SesslerAbstract:In an effort to increase the stability and control the platinum reactivity of platinum-Texaphyrin conjugates, two Pt(IV) conjugates were designed, synthesized, and studied for their ability to form DNA adducts. They were also tested for their anti-proliferative effects using wild-type and platinum-resistant human ovarian cancer cell lines (A2780 and 2780CP, respectively). In comparison to an analogous first-generation Pt(II) chimera, one of the new conjugates provided increased stability in aqueous environments. Using a combination of (1) H NMR spectroscopy and FAAS (flameless atomic-absorption spectrometry), it was found that the Pt(IV) center within this conjugate undergoes photoinduced reduction to Pt(II) upon exposure to glass-filtered daylight, resulting in an entity that binds DNA in a controlled manner. Under conditions in which the Pt(IV) complex is reduced to the corresponding Pt(II) species, these new conjugates demonstrated potent anti-proliferative activity in both test ovarian cancer cell lines.
Stuart W. Young - One of the best experts on this subject based on the ideXlab platform.
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photodynamic therapy of b16f10 murine melanoma with lutetium Texaphyrin
Journal of Investigative Dermatology, 1998Co-Authors: Kathryn W. Woodburn, Qing Fan, David Kessel, Yu Luo, Stuart W. YoungAbstract:Photodynamic therapy (PDT) of pigmented melanoma has generally been unsuccessful because of insufficient light penetration in such tissues. In this study, the responsiveness of the heavily pigmented B16F10 murine melanoma to lutetium Texaphyrin (PCI-0123), a water-soluble sensitizer with strong absorbance in the near infrared (700–760 nm), was examined. These studies were carried out in both normal and ApoE deficient C57BL/6 mice. The latter strain exhibits a lipoprotein profile more like humans (low density lipoprotein > high density lipoprotein) than rodents (high density lipoprotein >> low density lipoprotein). Under optimal conditions of drug dose, light dose, and interval between drug administration and irradiation – the median survival time of C57BL/6 tumor bearing mice was approximately doubled (29 d) compared with tumor bearing control animals (13 d). The life-span of the ApoE knockout mice was greater (33 d) than the C57BL/6 animals (23 d) when irradiation occurred 3 h after administration of a 10 μmol per kg drug dose. The greater efficacy of PDT in the ApoE deficient mice was associated with more rapid clearance of drug from the blood, greater accumulation of sensitizer in tumor tissue, and substantially greater drug binding to the very low density lipoprotein/low density lipoprotein plasma fraction. Confocal laser scanning microscopy showed that the predominant subcellular site of photosensitizer binding was to melanosomes; costaining was performed with Mel-5. Melanosomes are susceptible to oxidative stress. Photo-oxidation, mediated by PCI-0123 PDT, could potentially overload an already highly oxidized stressed state leading to cell death. The good tissue penetration depth achieved by PCI-0213 mediated PDT and the activation of melanosomes makes PDT of pigmented melanoma, for the first time, clinically relevant.
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Membrane incorporation of Texaphyrins
United States Patent and Trademark Office, 1997Co-Authors: Jonathan L. Sessler, Stuart W. Young, Tarak D. Mody, Meredith Wright, Darren MagdaAbstract:Compositions having a Texaphyrin-lipophilic molecule conjugate loaded into a biological vesicle and methods for imaging, diagnosis and treatment using the loaded vesicle are provided. For example, liposomes or red blood cells loaded with a paramagnetic Texaphyrin-lipophilic molecule conjugate have utility as a blood pool contrast agent, facilitating the enhancement of normal tissues, magnetic resonance angiography, and marking areas of damaged endothelium by their egress through fenestrations or damaged portions of the blood vascular system. Liposomes or cells loaded with a photosensitive Texaphyrin-lipophilic molecule conjugate can be photolysed, allowing for a photodynamic therapy effect at the site of lysis. Availability of red blood cells loaded with a photosensitive Texaphyrin-lipophilic molecule conjugate provides a method for delivering a photodynamic therapeutic agent to a desired site with a high concentration of oxygen. By presenting the agent in this way, it is expected that a patient will experience less toxicity.Board of Regents, University of Texas Syste
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gadolinium iii Texaphyrin a tumor selective radiation sensitizer that is detectable by mri
Proceedings of the National Academy of Sciences of the United States of America, 1996Co-Authors: Stuart W. Young, Gregory W Hemmi, Jonathan L. Sessler, Tarak D. Mody, William C Dow, Fan Qing, Anthony Harriman, Yunpeng Hao, Richard A. MillerAbstract:Gadolinium(III) Texaphyrin (Gd-tex2+) is representative of a new class of radiation sensitizers detectable by magnetic resonance imaging (MRI). This porphyrin-like complex has a high electron affinity [E1/2 (red.) approximately = -0.08 V versus normal hydrogen electrode] and forms a long-lived pi-radical cation upon exposure to hydrated electrons, reducing ketyl radicals, or superoxide ions. Consistent with these chemical findings, Gd-tex2+ was found to be an efficient radiation sensitizer in studies carried out with HT29 cells in in vitro as well as in in vivo single and multifraction irradiation studies with a murine mammary carcinoma model. Selective localization of Gd-tex2+ in tumors was confirmed by MRI scanning.
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lutetium Texaphyrin pci 0123 a near infrared water soluble photosensitizer
Photochemistry and Photobiology, 1996Co-Authors: Stuart W. Young, Jonathan L. Sessler, K W Woodburn, Meredith Wright, T D Mody, Q Fan, William C Dow, Richard A. MillerAbstract:Lutetium Texaphyrin, PCI-0123, is a pure, water-soluble photosensitizer with a large broad absorption band centered at 732 nm. The compound was tested for photodynamic therapy (PDT) effectiveness in a murine mammary cancer model. The Texaphyrin macrocycle as illustrated by magnetic resonance imaging and 14C-radiolabeled Texaphyrin studies was shown to be tumor selective; a tumor-to-muscle ratio of 10.55 was seen after 5 h. Lutetium Texaphyrin, at a drug dose of 20 mumol/kg with irradiation 5 h postinjection at 150 J/cm2 and 150 mW/cm2, had significant efficacy (P < 0.0001) in treating neoplasms of moderate size (40 +/- 14 mm3) and also had significant efficacy (P < 0.0001) in treating larger neoplasms (147 +/- 68 mm3). The PDT efficacy was correlated with the time interval between PCI-0123 administration and light exposure. A 100% cure rate was achieved when photoirradiation took place 3 h postinjection compared to 50% for 5 h using 10 mumol/kg and 150 J/cm2 at 150 mW/cm2. The PDT efficacy was attributable to the selective uptake/retention of the Texaphyrin photosensitizer in addition to the depth of light penetration achievable at the 732 nm laser irradiation.
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Experimental acute cerebral ischemia with reperfusion. Evaluation with gadolinium-Texaphyrin.
Investigative radiology, 1996Co-Authors: Stuart W. Young, Qing Fan, David M. Kunis, Gary K. SteinbergAbstract:RATIONALE AND OBJECTIVES The authors explore the potential usefulness of the new contrast medium gadolinium (Gd)-Texaphyrin (PCI-0101) in magnetic resonance imaging of experimental acute cerebral ischemia with reperfusion. METHODS Four New Zealand white rabbits underwent 2 hours of transorbital occlusion of the left internal carotid, anterior, and middle cerebral arteries, followed by 2 hours of reperfusion with normal saline. Immediately thereafter, the rabbits were injected with 25 mumol/kg of 2 mmol/L Gd-Texaphyrin and killed by barbiturate overdose. Postmortem T1- and T2-weighted coronal scans were performed at 1.5 Tesla and correlated with histopathologic findings. RESULTS Postcontrast T1-weighted images showed high signal within extensive cortical and basal ganglia infarcts. Areas of high signal on T1-weighted images were less extensive than on T2-weighted images, and corresponded to only a portion of the region of neuronal damage seen histologically. Signal intensity of infarcted brain on postcontrast T1-weighted images was significantly greater than normal brain in the contralateral hemisphere (P < 0.0014). CONCLUSIONS Experimental reperfused infarcts only 2 hours old demonstrate contrast enhancement with Gd-Texaphyrin.
Atsuhiro Osuka - One of the best experts on this subject based on the ideXlab platform.
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aromatic and antiaromatic cyclophane type hexaphyrin dimers
Chemistry-an Asian Journal, 2018Co-Authors: Akito Nakai, Tomoki Yoneda, Shinichiro Ishida, Kenichi Kato, Atsuhiro OsukaAbstract:A peripherally strapped [28]hexaphyrin takes a rectangular conformation and exhibits antiaromatic character. A cyclophane-type dimer consisting of such [28]hexaphyrins was synthesized from hexakis(pentafluorophenyl) [26]hexaphyrin via SN Ar reaction with allyl alcohol, one-pot intra- and intermolecular olefin metathesis under improved Hoveyda-Grubbs catalysis, and final reduction with NaBH4 . The cyclophane-type structures of [26]- and [28]hexaphyrin dimers have been revealed by X-ray analysis. Studies on the structural, optical, and electronic properties have led to a conclusion that there is no favorable electronic interaction between the two [28]hexaphyrin segments and thus no indication of 3D aromaticity.
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internally 2 5 thienylene bridged 46 decaphyrin annuleno annulene network consisting of mobius aromatic thia 28 hexaphyrins and strong huckel aromaticity of its protonated form
Angewandte Chemie, 2017Co-Authors: Takanori Soya, Hirotaka Mori, Yongseok Hong, Yun Hee Koo, Dongho Kim, Atsuhiro OsukaAbstract:Internally 1,3-phenylene- and 2,5-thienylene-bridged [46]decaphyrins 2 and 3 have been synthesized. While 2 shows modest aromatic character derived from the global 46π-conjugated circuit, 3 displays larger aromatic character owing to the contribution of an (annuleno)annulene-type network consisting of two twisted Mobius aromatic thia[28]hexaphyrin segments in addition to the global 46π-network. Upon protonation, these [46]decaphyrins underwent large structural changes to acquire strong aromaticity. Protonated 3 has been revealed to take on a planar structure composed of fused two triangular thia[28]hexaphyrin segments.
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a description of vibrational modes in hexaphyrins understanding the aromaticity reversal in the lowest triplet state
Angewandte Chemie, 2016Co-Authors: Young Mo Sung, Atsuhiro Osuka, Koji Naoda, Taegon Lee, Woojae Kim, Manho Lim, Dongho KimAbstract:Aromaticity reversal in the lowest triplet state, or Baird's rule, has been postulated for the past few decades. Despite numerous theoretical works on aromaticity reversal, experimental study is still at a rudimentary stage. Herein, we investigate the aromaticity reversal in the lowest excited triplet state using a comparable set of [26]- and [28]hexaphyrins by femtosecond time-resolved infrared (IR) spectroscopy. Compared to the relatively simple IR spectra of [26]bis(rhodium) hexaphyrin (R26H), those of [28]bis(rhodium) hexaphyrin (R28H) show complex IR spectra the region for the stretching modes of conjugated rings. Whereas time-resolved IR spectra of R26H in the excited triplet state are dominated by excited state IR absorption peaks, while those of R28H largely show ground state IR bleaching peaks, reflecting the aromaticity reversal in the lowest triplet state. These contrasting IR spectral features serve as new experimental aromaticity indices for Baird's rule.
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a very rapid electronic relaxation process in a highly conjugated zn ii porphyrin 26 hexaphyrin zn ii porphyrin hybrid tape
Physical Chemistry Chemical Physics, 2016Co-Authors: Hirotaka Mori, Atsuhiro OsukaAbstract:The excited-state energy relaxation processes of a Zn(II)porphyrin–[26]hexaphyrin–Zn(II)porphyrin triply linked hybrid tape, FZn, have been investigated by femtosecond transient absorption spectroscopy (TA), using a directly meso–meso linked hybrid trimer, HZn, as a reference compound. FZn has a very small S1–S0 energy gap through the expansion of π-conjugation and the absorption band at 1897 nm corresponds to its lowest singlet excited-state as a consequence of enhanced transition dipole moment that lies parallel to the long molecular axis. In TA measurements, we observe an energy transfer process (0.4 ps) from the Zn(II)porphyrin moiety to the [26]hexaphyrin core in HZn. In contrast to HZn, a biexponential decay with the time constants of 0.25 and 6.5 ps was observed in the decay profile of FZn. The detailed analysis of excitation wavelength, temperature and solvent dependent TA in FZn revealed that the electronic relaxation process (0.25 ps) from S1 to S0 is faster than the vibrational relaxation processes (5.9 ps) in the excited and ground states due to a very small S1–S0 energy gap through the expansion of π-conjugation. Accordingly, we demonstrate that electronic deactivation overtakes vibrational relaxation processes in a highly conjugated FZn.
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a mobius aromatic 28 hexaphyrin bearing a diethylamine group a rigid but smooth conjugation circuit
Angewandte Chemie, 2015Co-Authors: Tomohiro Higashino, Takanori Soya, Atsuhiro OsukaAbstract:The reaction of [26]hexaphyrin with triethylamine in the presence of BF3⋅OEt2 and O2 furnished a diastereomeric mixture of a diethylamine-bearing [28]hexaphyrin as a rare example of a Mobius aromatic metal-free expanded porphyrin. The Mobius aromaticity of these molecules is large, as indicated by their large diatropic ring currents, which are even preserved at 100 °C, owing to their internally multiply bridged robust structure with a smooth conjugation network. These molecules were reduced with NaBH4 to give an antiaromatic [28]hexaphyrin, and were oxidized with MnO2 to give aromatic [26]hexaphyrins, both through a Mobius-to-Huckel topology switch induced by a CN bond cleavage.
Darren Magda - One of the best experts on this subject based on the ideXlab platform.
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Recent Developments in Texaphyrin Chemistry and Drug Discovery
Inorganic chemistry, 2013Co-Authors: Christian Preihs, Darren Magda, Jonathan F. Arambula, Zahid H. Siddik, Heeyeong Jeong, Dongwon Yoo, Jinwoo Cheon, Jonathan L. SesslerAbstract:Texaphyrins are pentaaza expanded porphyrins with the ability to form stable complexes with a variety of metal cations, particularly those of the lanthanide series. In biological milieus, Texaphyrins act as redox mediators and mediate the production of reactive oxygen species (ROS). In this review, newer studies involving Texaphyrin complexes targeting several different applications in anticancer therapy are described. In particular, the preparation of bismuth and lead Texaphyrin complexes as potential α-core emitters for radiotherapy is detailed, as are gadolinium Texaphyrin functionalized magnetic nanoparticles with features that make them of interest as dual-mode magnetic resonance imaging contrast agents and as constructs with anticancer activity mediated through ROS-induced sensitization and concurrent hyperthermia. Also discussed are gadolinium Texaphyrin complexes as possible carrier systems for the targeted delivery of platinum payloads.
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Crown ether functionalized Texaphyrin monomers and dimers.
Journal of porphyrins and phthalocyanines, 2011Co-Authors: Christian Preihs, Darren Magda, Jonathan L. SesslerAbstract:The synthesis and characterization of two 18-crown-6 functionalized analogues of an extensively studied gadolinium Texaphyrin derivative, motexafin gadolinium (1, MGd), are reported. These are the monomeric and dimeric species, compounds 2 and 3, respectively. Both crown ether functionalized species proved to be stable at physiological pH and revealed distinct shifts in the UV spectrum when treated with sodium-, potassium-, ammonium- or zinc(II)-salts. Zinc(II) is believed to play a major role regulating apoptosis mechanisms in cancerous cells. Therefore, cytotoxicity studies of 2 and 3 were carried out using the Ramos cell line in the presence and absence of zinc(II).
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Gadolinium Texaphyrin (Gd-Tex)-Malonato-Platinum Conjugates: Synthesis and Comparison with Carboplatin in Normal and Pt-Resistant Cell Lines
Dalton transactions (Cambridge England : 2003), 2009Co-Authors: Jonathan F. Arambula, Darren Magda, Jonathan L. Sessler, Mark Fountain, Wen Hao Wei, Zahid H. SiddikAbstract:The synthesis of a new PEG-solubilized gadolinium Texaphyrin (Gd-Tex) conjugate containing a malonate-Pt(NH3)2 moiety is described. The effect of the tumor localizing Gd-Tex macrocycle on platinum activity was evaluated in cell culture. The malonate moiety, analogous to that present in carboplatin, is expected to release an aquated Pt(NH3)2 species under physiological conditions. The half-life in phosphate-buffered saline was found to be ca. 3 days at room temperature, and the hydrolytic product released from the conjugate was collected and confirmed as Pt-based by flameless atomic absorption spectrophotometry. Anti-proliferative activity was tested using A549 human lung cancer and A2780 human ovarian cancer cell lines. In both cell lines, the activity of the Gd-Tex conjugate was found to be similar to that of carboplatin. Efficacy against a Pt-resistant ovarian cell line greater than that displayed by carboplatin was also observed.
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Gadolinium Texaphyrin-methotrexate conjugates. Towards improved cancer chemotherapeutic agents.
Organic & biomolecular chemistry, 2005Co-Authors: Wen Hao Wei, Darren Magda, Mark Fountain, Dale Miles, Zhong Wang, Phil Lecane, Mimi Mesfin, Jonathan L. SesslerAbstract:Conjugates between methotrexate (MTX, Matrex®, N-[4-[[(2,4-diamino-6-pteridinyl)methyl]methylamino]benzoyl]-L-glutamic acid), an antifolate cancer chemotherapeutic to which resistance is often observed, and motexafin gadolinium (MGd), an experimental agent demonstrating selective tumor localization, are described. These systems were prepared in order to test whether linking these two species would produce agents with enhanced activity relative to MTX alone. Both ester- and amide-linked conjugates were synthesized starting from MGd and MTX. The ester conjugate showed greater in vitro anti-proliferative activity against the A549 lung carcinoma cell line at short incubation times than did MTX alone. Neither the amide conjugate, nor MGd, showed any observable activity under these in vitro conditions. These results are rationalized in terms of enhanced cellular uptake of both the ester and amide conjugates that is coupled with an effective rate of release (e.g., inherent or enzyme-mediated hydrolysis) in the case of the ester-linked conjugate, but not the corresponding amide system.
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synthesis of Texaphyrin conjugates
Pure and Applied Chemistry, 2004Co-Authors: Darren Magda, Wen Hao Wei, Zhong Wang, Nikolay Gerasimchuk, Pavel Anzenbacher, Jonathan L. SesslerAbstract:This paper summarizes recent synthetic efforts devoted to the generation of new, second-generation Texaphyrin-type drugs, specifically species that involve known or poten- tial anticancer agents covalently attached to a tumor-localizing Texaphyrin core. Particular emphasis will be placed on the strategies needed to prepare such systems, as well as on the choice of active group being subject to attachment.
Gregory W Hemmi - One of the best experts on this subject based on the ideXlab platform.
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Water soluble Texaphyrin metal complex preparation
United States Patent and Trademark Office, 1998Co-Authors: Jonathan L. Sessler, Gregory W Hemmi, Tarak D. ModyAbstract:The present invention is directed to methods for synthesizing water soluble hydroxy-substituted Texaphyrins retaining lipophilicity. The synthesis comprises condensing a diformyltripyrrole with an ortho-phenylenediamine to give a nonaromatic Texaphyrin having at least one hydroxy substituent, and oxidizing the condensation product to form an aromatic Texaphyrin metal complex having at least one hydroxy substituent. These expanded porphyrin-like macrocycles may be used for magnetic resonance imaging and for photodynamic therapy in the treatment of atheroma and tumors.Board of Regents, University of Texas Syste
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Pharmaceutical compositions comprising Texaphyrins
United States Patent and Trademark Office, 1997Co-Authors: Jonathan L. Sessler, Gregory W Hemmi, Tarak D. ModyAbstract:Texaphyrins are provided for use as radiation sensitizers. Advantageous properties of Texaphyrins for use as a radiation sensitizer include: i) a low redox potential which allows radiation-induced hydrated electrons to flow to Texaphyrin rather than neutralizing hydroxyl radicals, allowing hydroxyl radicals to cause cellular damage, ii) a relatively stable Texaphyrin radical that reacts readily to covalently modify neighboring molecules causing further cellular damage, iii) intrinsic biolocalization, and iv) indifference to the presence or absence of O.sub.2. These properties allow Texaphyrins to be particularly effective for treating the hypoxic areas of solid neoplasms. Methods of treatment for an individual having a neoplasm or atheroma include the use of a Texaphyrin as a radiation sensitizer and as an agent for photodynamic tumor therapy, or the use of a Texaphyrin for internal and for external ionizing radiation. Novel Texaphyrins are provided.Board of Regents, University of Texas Syste
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gadolinium iii Texaphyrin a tumor selective radiation sensitizer that is detectable by mri
Proceedings of the National Academy of Sciences of the United States of America, 1996Co-Authors: Stuart W. Young, Gregory W Hemmi, Jonathan L. Sessler, Tarak D. Mody, William C Dow, Fan Qing, Anthony Harriman, Yunpeng Hao, Richard A. MillerAbstract:Gadolinium(III) Texaphyrin (Gd-tex2+) is representative of a new class of radiation sensitizers detectable by magnetic resonance imaging (MRI). This porphyrin-like complex has a high electron affinity [E1/2 (red.) approximately = -0.08 V versus normal hydrogen electrode] and forms a long-lived pi-radical cation upon exposure to hydrated electrons, reducing ketyl radicals, or superoxide ions. Consistent with these chemical findings, Gd-tex2+ was found to be an efficient radiation sensitizer in studies carried out with HT29 cells in in vitro as well as in in vivo single and multifraction irradiation studies with a murine mammary carcinoma model. Selective localization of Gd-tex2+ in tumors was confirmed by MRI scanning.
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Metal complexes of Texaphyrins
United States Patent and Trademark Office, 1996Co-Authors: Jonathan L. Sessler, Gregory W Hemmi, Tarak D. Mody, Vladimir A. KralAbstract:Texaphyrins are provided for use as radiation sensitizers. Advantageous properties of Texaphyrins for use as a radiation sensitizer include: i) a low redox potential which allows radiation-induced hydrated electrons to flow to Texaphyrin rather than neutralizing hydroxyl radicals, allowing hydroxyl radicals to cause cellular damage, ii) a relatively stable Texaphyrin radical that reacts readily to covalently modify neighboring molecules causing further cellular damage, iii) intrinsic biolocalization, and iv) indifference to the presence or absence of O.sub.2. These properties allow Texaphyrins to be particularly effective for treating the hypoxic areas of solid neoplasms. Methods of treatment for an individual having a neoplasm or atheroma include the use of a Texaphyrin as a radiation sensitizer and as an agent for photodynamic tumor therapy, or the use of a Texaphyrin for internal and for external ionizing radiation. Novel Texaphyrins are provided.Board of Regents, University of Texas Syste
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Treatment of neoplastic tissue by water-soluble Texaphyrine metal complexes
United States Patent and Trademark Office, 1996Co-Authors: Jonathan L. Sessler, Gregory W Hemmi, Tarak D. ModyAbstract:The present invention relates to the use of water-soluble Texaphyrin-diamagnetic metal complexes retaining lipophilicity as photosensitizers in the treatment of benign and malignant neoplastic tissue.Board of Regents, University of Texas Syste
