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Different pH-sensitive, randomly- and terminally-alkylated N-isopropylacrylamide (NIPAM) copolymers were synthesized and used to prepare pH-responsive polymeric micelles (PM). These copolymers were modified from previously-studied copolymers by incorporating an additional hydrophilic monomer, N-vinyl-2-pyrrolidone (VP) to decrease uptake by the mononuclear phagocyte system (MPS) and improve localization in tumors. VP lowered the phase transition pH of the copolymers but did not affect the onset of micellization. The in vitro cytotoxicity of the copolymers was evaluated on EMT-6 mouse mammary tumor cells in comparison to Cremophor EL (CRM). The anticancer photosensitizer aluminum chloride phthalocyanine (AlClPc) was loaded into the PM with a standard dialysis procedure. Biodistribution and in vivo photodynamic activity were then evaluated in Balb/c mice bearing intradermal EMT-6 tumors. All NIPAM copolymers demonstrated substantially lower cell cytotoxicity than the control surfactant CRM. In vivo, similar AlClPc tumor uptake was observed for the PM and CRM formulations. However, the PM appeared to exhibit greater activity in vivo than CRM formulation at an AlClPc subtherapeutic dose. Therefore, NIPAM-based copolymers containing VP units represent promising alternatives for the formulation of poorly water-soluble phthalocyanines.

Immunophototherapy of cancer combines the specificity of a monoclonal antibody (MAb) to an overexpressed tumor marker with the phototoxic properties of the conjugated dye. To analyze the potential role of internalisation of the dye on photo-induced cytotoxicity, we compared two target antigens, carcinoembryonic antigen (CEA) that does not internalise and ErbB2 that does. Human ovarian carcinoma SKOv3 cells that express a high level of ErbB2 were transfected with the CEA cDNA. Using FACS analysis, the resulting cell line, SKOv3-CEA-1B9, demonstrated comparable levels of expression of the two target antigens. Aluminium tetrasulfophthalocyanine (AlPcS 4) was covalently coupled to anti-CEA MAb 35A7, anti-ErbB2 MAb FSP77 and a non-specific MAb PX, via a five-carbon sulfonamide spacer chain (A 1) at molar ratios ranging from 6 to 9 moles of AlPcS 4 per mole of MAb. The 35A7-(AlPcS 4 A 1)8 conjugate induced 68% growth inhibition of the SKOv3-CEA-1B9 cell line after a 20 h incubation at 2.50 μg/ml (based on AlPcS 4 A 1 content) following light exposure. However, the FSP77-(AlPcS 4 A 1)6 conjugate gave a 51% growth inhibition for an AlPcS 4 A 1 concentration as low as 0.04 μg/ml after the same incubation time and exposure to the same light dose. At a 1.25 μg/ml AlPcS 4 A 1 concentration, the FSP77-(AlPcS 4 A 1)6 conjugate gave a 67% growth inhibition after an incubation time as short as 1 h, reaching a 96% inhibition after an 8 h incubation time. Using an unique cell line that expresses two different target antigens, we demonstrated a clear advantage of an internalising over a non-internalising MAb-dye conjugate in terms of phototoxic efficacy. In vivo evaluation of the photodynamic properties of the conjugates is in progress. © 2001 Cancer Research Campaign http://www.bjcancer.com © 2001 Cancer Research Campaign

pH-sensitive polymeric micelles of randomly and terminally alkylated N-isopropylacrylamide copolymers were prepared and characterized. Aluminium chloride phthalocyanine (AlClPc), a second generation sensitizer for the photodynamic therapy of cancer, was incorporated in the micelles by dialysis. Their photodynamic activities were evaluated in-vitro against EMT-6 mouse mammary tumour cells and in-vivo against EMT-6 tumours implanted intradermally on each hind thigh of Balb/c mice. pH-sensitive polymeric micelles were found to exhibit greater cytotoxicity in-vitro than control Cremophor EL formulations. In the presence of chloroquine, a weak base that raises the internal pH of acidic organelles, in-vitro experiments demonstrated the importance of endosomal/lysosomal acidity for the pH-sensitive polymeric micelles to be fully effective. Biodistribution was assessed by fluorescence of tissue extracts after intravenous injection of 2 μmol kg−1 AlClPc. The results revealed accumulation of AlClPc polymeric micelles in the liver, spleen and lungs, with a lower tumour uptake than AlClPc Cremophor EL formulations. However, polymeric micelles exhibited similar activity in-vivo to the control Cremophor EL formulations, demonstrating the higher potency of AlClPc polymeric micelles when localized in tumour tissue. It was concluded that polymeric micelles represent a good alternative to Cremophor EL preparations for the vectorization of hydrophobic drugs.

Palladium catalysts offer a rich and highly versatile chemistry for the synthesis of novel porphyrins and phthalocyanines. These mild and flexible reactions have been used extensively in the preparation of interesting porphyrins and phthalocyanines, either in the synthesis of substituted precursors or in the modification of pre-existing macrocycles. For these tetrapyrrolic compounds, metal-mediated reactions such as these offer extensive benefits, which have been taken advantage of in order to add novel substituents, synthesize naturally occurring molecules and prepare multi-macrocyclic arrays. This review gives an overview of the use of palladium catalysts in the synthesis of porphyrins and phthalocyanines along with the applications of some of the compounds prepared.

The potential use of unsubstituted aluminium phthalocyanine (AlClPc) as a sensitizer for photodynamic therapy (PDT) of cancer has not been fully exploited in spite of its higher efficiency as compared to the sulphonated derivatives. This is largely due to the strong hydrophobic character of AlClPc which renders the material difficult to formulate for in vivo administration. We prepared two water-soluble derivatives of AlClPc by axial coordination of polyethyleneglycol (PEG, MW 2000) or polyvinylalcohol (PVA, MW 13 000–23 000) to the central aluminium ion. Their photodynamic activities were evaluated in vitro against the EMT-6 mouse mammary tumour cells and in vivo against the EMT-6 and the colon carcinoma Colo-26 tumours implanted intradermally in Balb/c mice. Pharmacokinetics were studied in the EMT-6 tumour-bearing mice. After 1 h incubation, the light dose required to kill 90% of cells (LD90) was at least three times less for AlClPc (Cremophor emulsion) as compared to AlPc–PEG and AlPc–PVA, while after 24 h incubation all three preparations were highly phototoxic. All three dye preparations induced complete EMT-6 tumour regression in 75–100% of animals at a low drug dose (0.25 μmol kg−1) following PDT (400 J cm−2, 650–700 nm) at 24 h pi. Complete tumour regression in the Colo-26 tumour model was obtained in 30% of mice at a dose of 2 μmol kg−1. In the non-cured animals, AlPc–PVA induced the most significant tumour growth delay. This dye showed a prolonged plasma half-life (6.8 h) as compared to AlClPc (2.6 h) and AlPc–PEG (23 min), lower retention by liver and spleen and higher tumour-to-skin and tumour-to-muscle ratios. Our data demonstrate that addition of hydrophilic axial ligands to AlPc, while modifying in vitro and in vivo kinetics, does not reduce the PDT efficiency of the parent molecule. Moreover, in the case of the polyvinylalcohol derivative, axial coordination confers advantageous pharmacokinetics to AlPc, which makes this photosensitizer a valuable, water soluble candidate drug for clinical PDT of cancer. © 1999 Cancer Research Campaign

We report the novel cooperative properties of a complex obtained by self-assembling in solution a tetracationic cobalt porphyrin, CoIIP4+, and a tetraanionic sulfoaluminum phthalocyanine, AlIIIPc4-. In the ground state, the complex displays a charge transfer character, CoII-δ P4+/(AlIIIPc4-)+δ, and the oxidation of the phthalocyanine moiety is catalyzed in the presence of its partner. In aerated media, the neutral complex strongly binds molecular oxygen to form a stable zwitterionic species, -O2CoIIP4+/(AlIIIPc4-)+˚. The zwitterion can revert to the neutral form CoII-δP4+/(AlIIIPc4-)+δ upon vigourous bubbling of the solution with an inert gas (N2, Ar) or under light stimuli. In the excited state, the complex photoejects the oxygen and relaxes to the ground state via a triplet excited state. The latter species can transfer its excess energy to nearby oxygen molecules. The mechanism of photoproduction of 1O2 was studied via steady-state and time-resolved absorption and fluorescence techniques over a wide ti...

Aluminium phthalocyanines sulfonated to a different degree ( AlPcS n) and consisting of various isomeric species were studied by spectroscopic techniques to determine their tendencies to form dimers and aggregates. These characteristics were compared with the cell-penetrating properties of the species, using the Ehrlich ascites mouse tumor cell line, to arrive at structure-activity relationships. AlPcS n preparations consisting of the least number of isomeric species exhibited the highest tendency to form dimers and aggregates, whereas the more complex preparations, consisting of many isomeric products, showed more consistent monomeric features in aqueous environments. Uptake in cells was shown to correlate well with the overall hydrophobicity of the preparation and inversely with its degree of aggregation in the extracellular environment. Among the purified, single isomeric AlPcS n the amphiphilic disulfonated AlPcS 2a , enriched in positional isomers featuring sulfonate groups on adjacent phthalic subunits, showed the best membrane-penetrating properties. Even higher cell uptake was observed for the AlPcS 2mix reflecting a combination of optimal lipophilicity and a low degree of aggregation. Similarly, in the case of AlPcS 4, the pure isomeric compound showed less cell uptake than the mixed isomeric preparation of similar hydrophobicity, reflecting the higher degree of aggregation invoked by its symmetrical structure. Our data indicate that mixed sulfonated phthalocyanine preparations may exert higher photodynamic efficacy in biological applications as compared to the pure isomeric constituents.

The synthesis and brain uptake in mice of the radioiodinated derivatives of N,N-dimethyl-N'-(iododimethoxyphenyl)-1,3-propanediamine, as well as the N-substituted derivatives of (iodoalkylphenyl)isopropyl, iodoalkylphenylethylamine and 3,4-(methylenedioxy)phenyl-amphetamine (MDA) are described. These compounds contain structural features of both IMP and HIPDM, the cerebral perfusion agents currently in clinical use. The radiolabeled analogs were obtained via the [125I]I exchange method, or by [125I]NaI treatment of the iodo-free precursor in the presence of an oxidant. Following intravenous injection in mice, all compounds showed important radioactivity concentrations in the lungs and kidneys. The N-substituted (iodoalkylphenyl)isopropyl and iodoalkylphenyl-ethylamine derivatives displayed a high initial brain uptake (> 10% IDg-1) followed by a rapid clearance phase, resulting in lower brain-to-blood ratios as those reported for IMP and HIPDM. In contrast, N,N-dimethyl-N'-(iododimethyphenyl)-1,3-propanediamine derivatives featuring the iodo substituent on the benzene carbon adjacent to the methyl amine group and the methoxy substituents on the 2,5- or 2,4-positions, showed low but more persistant brain uptake. Combined with fast blood clearance, this resulted in high brain-to-blood ratios at later time points. Among all compounds tested, the highest brain-to-blood ratio was observed with compound N,N-dimethyl-N'-(6-iodo-3,4-dimethyoxyphenyl)-1,3-propanediamine (27e), reaching a maximum of > 20 at 12 h post-injection.

Summary Photodynamic therapy (PDT) is a treatment modality for a number of human neoplasms. The drug preparation most widely used in current clinical trials is photofrin. Photofrin lacks definite structure and as a result the interpretation of its pharmacokinetic data is difficult. Thus the development of new sensitizers of known structure such as the phthalocyanines and naphthalocyanines has been proposed. In our approach, we have studied the use of tetraazaporphyrins (porphyrazines) as sensitizers. This class of sensitizers has received very little attention. A number of porphyrazines were synthesized via the cyclization of tricyanovinyl amines and dinitrile amines in pentanol solution of magnesium oxide. These porphyrazines were converted to their respective zinc chelates and tested for their stability in acidic media and for their ability to photoinactivate cells in culture. Results indicate that these porphyrazines show promise and must be investigated further for applications in PDT.

Zinc phthalocyanine (ZnPc) is a second-generation photosensitiser for the photodynamic therapy (PDT) of cancer. Unsubstituted ZnPc is, however, highly insoluble in most common solvents, and for clinical applications the material needs to be incorporated in liposomes. We report a simple, alternative procedure to formulate ZnPc through non-covalent binding to bovine serum albumin (BSA). Intravenous administration of ZnPc-BSA preparations, at a molar ratio of 11:1 and at a ZnPc dose equivalent to 0.5 mol kg-1, to tumour-bearing mice followed 24 h later by PDT was shown to provide tumour control in two different models, the EMT-6 tumour in Balb/c mice and the human colon T380 carcinoma in nude mice. Analysis of serum fractions from treated animals showed that ZnPc readily redistributes over the serum high-density lipoprotein (HDL) fraction. We also demonstrated the absence of hepatic toxicity of the ZnPc-BSA preparation by monitoring the hepatic cytochrome P450 activity in treated animals and the viability of human cultured hepatocytes.

La photochimiotherapie (PCT) du cancer consiste a traiter les tissus tumoraux avec la lumiere visible apres l'administration systemique d'agents photosensibilisants du type des porphyrines. Nous avons recemment demontre le potentiel des derives bis(alkylsiloxy) 2,3-naphtalocyanine. de silicium comme photosensibilisateurs pour la PCT, dans la partie rouge lointain du spectre, la ou la transmission de la lumiere par les tissus est optimale. Le derive bis(dimethylthexylsiloxy) SiNc administre a 0.1 μmole/Kg 24 h avant la PCT est apparu le plus actif, induisant la regression de la tumeur EMT-6 chez plus de 80% des souris BALB/c. Ces resultats ont ete obtenus avec une longueur d'onde d'excitation fixee a 780 ni, qui represente le maximum d'absorption du compose a l'etat non aggrege. Le present travail porte sur l'evaluation de la reponse tumorale en fonction de la longueur d'onde d'excitation fixee entre 770 ni et 790 ni. Le spectre d'action de l'efficacite anti-tumorale du derive bis(dimethylthexylsiloxy) SiNc correspond bien au spectre d'excitation de fluorescence du compose.

Hexadecafluorinated zinc phthalocyanine (ZnPcF16), an analogue of zinc phthalocyanine (ZnPc) in which all hydrogen atoms have been substituted by fluorine, was prepared as a single isomeric product via the condensation of tetrafluorophthalonitrile with zinc acetate. Fluorination renders the ZnPc soluble in most common solvents. The photodynamic properties and pharmacokinetics of the ZnPcF16 were evaluated in EMT-6 tumour-bearing Balb/c mice using 65Zn-radiolabelled analogues. Both dyes, administered i.v. at 1 mumol kg-1 as Cremophor emulsions, revealed good tumour uptake [approximately 8-9 per cent of the injected dose per g tissue (%IDg-1)] at 24 h post injection (p.i.), with the fluorinated dye reaching higher concentrations (approximately 11%IDg-1) at 48 h p.i. and subsequently higher tumour-blood ratios due to rapid blood clearance. ZnPcF16 at a dose of 5 mumol kg-1 (4.3 mg kg-1) induced complete tumour regression after phototherapy (24 h p.i., 650-700 nm band, 360 J cm-2, 200 mW cm-1). At a dose of 2 mumol kg-1 and phototherapy at 24 h p.i., the tumour volume doubling time increased to 11 days vs 6 days for the control tumours. A similar tumour growth delay was observed when phototherapy was conducted at 48 h or 72 h after dye injection implying that tumour response correlates with tumour dye concentrations rather than serum concentrations. As a result of its low solubility, the administered dose of ZnPc was limited to 1 mumol kg-1 and at this drug level significant tumour response was only observed when the dye was solubilised as the pyridinium salt. Isolation of the neoplastic cells after in vivo dye administration and in vitro exposure to red light followed by a colony formation assay showed that the ZnPcF16 exhibited a 1-2 order of magnitude higher potential for direct cell killing as compared with Photofrin and about a five times lower efficiency than ZnPc. However, all three photosensitisers induced complete occlusion of tumour vasculature immediately after PDT, suggesting that tumour regression mainly resulted from vascular stasis. The ZnPcF16 offers several advantages over ZnPc for clinical applications, including improved solubility in most solvents, resulting in facilitated drug formation, favourable pharmacokinetics as well as the potential use in fluorine magnetic resonance (F-MR) imaging.

Etoposide (VP-16) is an anti-cancer drug commonly used against several types of tumours and leukaemia, either alone or in combination chemotherapy. Photodynamic therapy (PDT) is another, relatively new modality for treatment of various malignancies. The interactions between VP-16 and PDT, using aluminium tetrasulphophthalocyanine as photosensitiser, in K562 human leukaemic cells were investigated. Cell responses to individual and combined drug treatment under different experimental conditions revealed synergistic drug toxicity. The latter was evident from various events of cell response, including supra-additive accumulation of cells in G2/M cell cycle phase and endonucleolytic DNA fragmentation (apoptosis). The involvement of the cellular antioxidant system in the synergistic interactions of photosensitisation and VP-16 is proposed. Images Figure 5

Les mecanismes des alterations tissulaires induites par la therapie photodynamique avec le Photofrin ou des phtalocyanines d'aluminium di- ou tetrasulfonee (AlPcS 2 ou AlPcS 4 ) ont ete etudies sur la peau et la tumeur mammaire EMT6 de souris. L'oedeme, la congestion et des alterations cytopathiques des cellules neoplasiques sont deja visibles 3 h apres le traitement. L'hemorragie, focale a 3 h et severe a 24 h, a ete uniquement observee dans les tumeurs. Les dommages vasculaires causes par AlPcS 2 ou AlPcS 4 sont apparus plus tardivement que la necrobiose, ce qui suggere fortement l'implication de l'effet direct dans le mecanisme d'action de ces 2 composes, a la difference du Photofrin, qui semble induire une necrose par infarctus hemorragique

La photochimiotherapie (PCT) du cancer repose sur l'activation par la lumiere rouge d'agents photosensibilisants du type des porphyrines, qui sont retenus preferentiellement par les tissus tumoraux apres leur administration systemique. Au cours des dernieres annees, plusieurs classes de composes ont ete proposes comme nouveaux photosensibilisateurs. Parmi eux, les naphtalocyanines presentent l'avantage d'une absorption elevee vers 780 nm, ou la transmission de la lumiere par les tissus est maximale. Nous avons donc prepare quatre derives 2,3-naphtalocyanines de silicium, substitues axialement avec deux chaines siloxy-alkyles de longueur croissante

Notre etude porte sur les photosensibilisateurs suivants: bis-(tri-n-hexylsiloxy) (compose I), bis(dimethyloctadecylsiloxy) (II), bis-(dimethylthexylsiloxy) (III), bis(tert-butyldimethylsiloxy) (IV) 2,3-naphtalocyanine de silicium (SiNc) et 2,3-naphtalocyanine de zinc (ZnNc) (V). Une methode d'etalonnage, pour obtenir le rendement quantique d'oxygene singulet ( 1 O 2 ), a ete developpee avec l'utilisation d'un capteur de 1 O 2 , le 9,10-diphenylanthracene (DPA). Nous avons ainsi calcule des rendements quantiques de 1 O 2 . Les valeurs suivantes ont ete obtenues: pour le compose I, Φ=0,38; pour le II, Φ=0,39; pour le III, Φ=0,39 et pour le IV, Φ=0,22

Six sulfonated metallophthalocyanines, chelated with either aluminum or zinc and sulfonated to different degrees, were studied in vivo for their photodynamic activity in a rat skin-fold chamber model. The chamber, located on the back of female WAG/Rij rats, contained a syngeneic mammary carcinoma implanted into a layer of subcutaneous tissue. Twenty-four hours after intravenous administration of 2.5 μmol/kg of one of the dyes, the chambers received a treatment light dose of 600 J/cm2 with monochromatic light of 675 nm at a power density of 100 mW/ cm2. During light delivery and up to a period of 7 days after treatment, vascular effects of tumor and normal tissue were scored. Tumor cell viability was determined by histology and by reimplantation of the chamber contents into the skin of the same animal, either 2 h after treatment or after the 7 day observation period. Vascular effects of both tumor and subcutaneous tissue were strongest with dyes with the lowest degree of sulfonation and decreased with increasing degree of sulfonation. Tumor regrowth did not occur with aluminum phthalocyanine mono- and disulfonate and with zinc phthalocyanine monosulfonate. With the protocol that was used, complete necrosis without recovery was only observed when reimplantation took place at the end of the 7 day follow-up period. Reimplantation 2 h after treatment always resulted in tumor regrowth. At this interval, the presence of viable tumor cells was confirmed histologically. In general tumor tissue vasculature was more susceptible to photodynamic damage than vasculature of the normal tissue. The effect on the circulation of both tumor and normal tissue increased with decreasing degree of sulfonation. Based on this study, the photodynamic effects using the six sulfonated metallophthalocyanines on the vasculature can be ranked from high to low as: AlPcS2= ZnPcS1 > AIPcS1 > AIPcS4 > ZnPcS2 > ZnPcS4.

Zinc phthalocyanine substituted with four hydroxyl groups attached to the macrocycle, either directly or via spacer chains of three or six carbon atoms, were tested for their photodynamic ability to inactivate Chinese hamster lung fibroblasts (line V-79) in vitro, and to induce regression of EMT-6 tumours grown subcutaneously in Balb/c mice. Their potential to inflict direct cell killing during photodynamic therapy was investigated by examining vascular stasis immediately following photoirradiation using fluorescein as a marker, and also by an in vivo/in vitro EMT-6 cell survival assay. Both of the tetraalkylhydroxy substituted zinc phthalocyanines are effective photodynamic sensitisers in vivo with the tetrapropylhydroxy compound exhibiting about twice the activity of the tetrahexylhydroxy analogue. The differences in activities were accentuated in vitro, the tetrapropylhydroxy compound was two orders of magnitude more potent than the tetrahexylhydroxy analogue in photoinactivating V-79 cells. The tetrahydroxy compound lacking spacer chains failed to exhibit photodynamic activity in either system. Tumour response with the active compounds was preceded by vascular stasis immediate following irradiation which suggests, together with the absence of activity in the in vivo/in vitro assay, that tumour regression involves an indirect response to the photodynamic action rather than direct cell killing. These data demonstrate the importance of the spatial orientation of functional groups around the macrocycle of photosensitisers for their efficacy in the photodynamic therapy of cancer.

The spectral and electrochemical properties of tetrabenzo[5,10,15]triazaporphine (TBTAP) and its magnesium derivatives having a long alkyl chain attached to the meso carbon have been studied. Both metal-free and metallated species show typical metal-free phthalocyanine-like spectra. Two reduction and two oxidation redox couples have been observed. The cation, anion, and dianion species of these porphyrin derivatives have been electrochemically generated and their electronic spectra are recorded.

The effect of human serum components on the photodynamic activity of zinc phthalocyanine (ZnPc) toward Chinese hamster fibroblasts (line V-79) was studied. Photodynamic activities were correlated with cellular uptake of radiolabeled [65Zn]ZnPc, which allowed corrections to be made for the amount of sensitizer present in the cells at the time of irradiation and to express photodynamic efficiencies on a cellular dye concentration basis. All serum components, with the exception of high-density lipoproteins, inhibit uptake of ZnPc by V-79 cells, when compared to incubation of ZnPc with the same cells in serum-free medium. High-density lipoproteins increased ZnPc uptake by 23%, but the photodynamic efficiency corrected for the cellular ZnPc concentration was unaffected. Very low-density lipoprotein and globulins decreased ZnPc cell uptake but likewise did not affect the cellular photodynamic efficiency of the dye. In contrast low-density lipoprotein and albumin, while inhibiting ZnPc cell uptake, increased the cellular photodynamic efficiency of ZnPc, suggesting that these proteins facilitate localization of the dye at cellular targets sensitive to photodynamic damage and vital to cell survival. We conclude from these results that association of ZnPc with serum components can have important, and widely differing, effects on both degree of uptake and cellular distribution of the photosensitizer.

We have prepared the 2- and 4-fluoro derivatives of 16α-[18F]fluoroestradiol (FES) (4a, b) and 11β-OMe-FES (4c, d). Electrophilic substitution of estrone or 11β-OMe-estrone with N-fluoropyridinium salt gave the 2-and 4-F derivatives 1, which were converted to the triols 2 and subsequently to the reactive 16β, 17β-cyclic sulfates 3. Stereoselective opening of the cyclic sulfates via nucleophilic fluorination with Me4NF or [18F]F- and removal of the protecting ether and sulfate groups via rapid acid hydrolysis gave 4a-d or [16α-18F]-(4a-d).

Aluminium phthalocyanines substituted to different degrees with hydrophilic sulphonic acid and hydrophobic phthalimidomethyl groups were investigated in vivo as new agents for the photodynamic therapy of malignant tumours. Parameters studied included the photodynamic action on EMT-6 mammary tumours in BALB/c mice, the therapeutic window and the potential for direct cell killing, assayed via an in vivo/in vitro test. Although the efficiency of photoinactivation of the EMT-6 tumour increases by a factor of ten with reduction of the number of sulphonic acid groups from four to two, no further effect was seen with the addition of the hydrophobic phthalimidomethyl groups. Addition of the latter groups however increased the potential for direct cell killing by a factor of two and expanded the therapeutic window by a factor of four, thus improving the usefulness of the dye as a photosensitiser for the photodynamic therapy of cancer.

High-performance liquid chromatography-thermospray mass spectrometry was applied to the analysis of various radiation-induced decomposition products of thymidine including N-(2-deoxy-β- d - erythro -pentofuranosyl)formamide and the various diastereomers of 5,6-dihydroxy-5,6-dihydrothymidine, 5-hydroxy-5,6-dihydrothymidine and 5,6-dihydrothymidine. This method combines high sensitivity and product resolution, rendering it particularly useful for monitoring the formation of radiation-induced base damage within DNA.

Proposees comme photosensibilisateurs pour un nouveau traitement contre le cancer appele la therapie photodynamique, les phtalocyanines sulfonees de gallium ont ete substituees avec des groupes tertio-butyles afin d’accentuer leur caractere hydrophobe et amphiphile permettant d’augmenter leur accumulation cellulaire et ainsi leur potentiel photocytotoxique. Parmi les derives etudies, la phtalocyanine disulfonee de gallium avec deux groupes tertio-butyles en positions adjacentes a ete la plus active en demontrant un gain d’efficacite photocytotoxique relative de pres de cinq comparativement a la phtalocyanine disulfonee de gallium depourvue des groupes tertio-butyles. Ces substituants, en plus d’accentuer l’accumulation cellulaire, permettraient aux phtalocyanines de mieux se distribuer pres de la cible photosensible intracellulaire ou optimiseraient l’interaction moleculaire entre la phtalocyanine et la molecule cible.

Les proprietes photophysiques de deux dimeres mixtes de porphyrine et de phtalocyanine lies de facon covalente, soit par un atome d’oxygene (dimere I), soit par un pont amide (dimere II) ont ete etudiees. Dans les deux cas, lors de l’excitation selective de la porphyrine, un transfert d’energie vers la phtalocyanine a lieu. Ce processus est particulierement efficace dans le dimere II pour lequel le rendement de transfert est proche de l’unite.

Les principales reactions d’oxydation radicalaire des radicaux hydroxyles (aspects cinetiques et structuraux sur les radicaux formes transitoirement et caracterisation des produits diamagnetiques qui en resultent) induites dans les quatre nucleosides de l’ADN en solution aqueuse aeree sont presentees. Les donnees recentes sur les reactions de transformation des radicaux cations puriniques et pyrimidiniques de ces memes composes modeles de l’ADN, qui sont d’importants intermediaires de l’effet direct du rayonnement ionisant et de reactions photosensibilisees, sont aussi discutees. L’accent est mis tout particulierement sur les analogies qui ont ete observees concernant la formation des radicaux oxydants par action des radicaux OH et par hydratation ou deprotonation des radicaux cations. Un bilan des reactions radicalaires de type oxydatif des bases puriniques et pyrimidiniques dans l’ADN isole, cellulaire et tissulaire est aussi presente.

To evaluate the biodistribution and tumor uptake of chlorogallium tetraoctadecyloxy phthalocyanine, a potential new drug for the photodynamic therapy of cancer, we prepared the radioactive 67Ga-labeled complex and its water soluble sulfonated derivative. The non-sulfonated dye was obtained by condensation of octadecyloxyphthalonitrile in the presence of a mixture of 67Ga and 69Ga chloride. The sulfonated derivative was obtained by treatment of the condensation product with oleum. As singlet molecular oxygen has been implicated in the photodynamic action of phthalocyanines (Pcs), the quantum yield of singlet oxygen (φΔ) was evaluated for chlorogallium tetraoctadecyloxy Pc, and also its zinc, aluminum and metal free analogues. After intraperitoneal administration of the non-sulfonated dye into RIF tumor bearing C3H mice, a very high 67Ga-uptake was observed in the spleen, while tumor radioactivity remained low during the 3 day study. The in vivo stability of the 67Ga-phthalocyanine complex was confirmed by comparing the distribution pattern with that of 67Ga-citrate, which proved to be significantly different. Intravenous injection of the sulfonated dye resulted in an overall lowering of 67Ga-uptake by most tissues, particularly in the spleen, while tumor radioactivities were slightly higher. These data suggest that amphiphilic photosensitizers, containing both polar sulfonate groups and long aliphatic substituents, exhibit the best distribution pattern for both imaging and photodynamic therapy of tumors.

The biodistribution and metabolism of 14C-labeled disulfonated and trisulfonated gallium phthalocyanine (Ga-PcS) was studied in radiation-induced fibrosarcoma tumor-bearing C3H mice. The [14C]Ga-PcS compounds were prepared via the condensation of [14C]phthalic acid and sulfophthalic acid in the presence of gallium chloride and characterized by their spectroscopic and chromatographic properties. The tissue concentrations of the dyes was measured by scintillation counting of the 14C and by extraction and fluorescence measurements. Elevated dye levels were found in the liver, lungs, kidneys and spleen as well as in the tumor. Lower sulfonation of Ga-PcS favored liver and spleen uptake whereas higher dye sulfonation resulted in greater kidney uptake. Both dyes showed high tumor uptake with peak concentrations exceeding those of most tissues except for the liver in the case of Ga-PcS2. The highest tumor uptake was observed with Ga-PcS3. Both dyes were slowly excreted from the body. The liver—feces pathway was favored in the case of Ga-PcS2 with high activities persisting in the liver, even after 21 days. The Ga-PcS3 was preferentially excreted via the kidney—urine pathway. High performance liquid chromatography analysis of the liver and tumor extracts of [14C]Ga-PcS3-treated animals did not reveal desulfonation of the dye.

Numerous detrimental side effects and/or lack of water-solubility of anticancer drugs often prove dose-limiting in chemotherapy. Water-soluble polymeric drug carriers may overcome/minimise many of these limitations.Aspartic acid polymers to which ferrocene-containing antineoplastic agents are covalently bound, were tested for cytotoxicity against murine EMT-6 cancer cells. Cell survival was measured by means of the colorometric 3-(4,5-dimethylthiazol-2-yl)-diphenyltertrazolium bromide assay.The 90% lethal dosage of pure 3-ferrocenylbutanoic acid is 452 microg/mL LD90 for the polymeric derivative, expressed in terms of 3-ferrocenylbutanoic acid content, is only 65 microg/ml. A polymer structural effect in drug activity was evident: longer side chains linking drugs to polymer backbones enhanced drug activity. Drug activity is also enhanced if drug modifications (to enable drug anchoring) resulted in a lower ferrocenyl reduction potential.The effectivity of antineoplastic drugs may be enhanced by covalently anchoring them on suitable biodegradable water-soluble polymeric drug carriers.

Palladium catalysts offer a rich and highly versatile chemistry for the synthesis of novel porphyrins and phthalocyanines. These mild and flexible reactions have been used extensively in the preparation of interesting porphyrins and phthalocyanines, either in the synthesis of substituted precursors or in the modification of pre-existing macrocycles. For these tetrapyrrolic compounds, metal-mediated reactions such as these offer extensive benefits, which have been taken advantage of in order to add novel substituents, synthesize naturally occurring molecules and prepare multi-macrocyclic arrays. This review gives an overview of the use of palladium catalysts in the synthesis of porphyrins and phthalocyanines along with the applications of some of the compounds prepared.

The aim of this study was to investigate a possible relationship between 99mTc-methoxyisobutyl isonitrile (MIBI) uptake and the estrogen receptor (ER) status of breast tumors as determined by 11beta-methoxy-(17alpha,20Z)-[123I]iodovinylestradi ol (MIVE) scintimammography.Thirteen patients referred for MIVE scintimammography after abnormal mammography or finding of a suspect mass on physical examination were injected intravenously with MIVE. Planar images of the breasts and axillary region were taken with both radiopharmaceuticals and compared with pathologic examination of the tumor tissue and in vitro ER quantification.The presence of cancerous tissue, as indicated by MIBI uptake, is a prerequisite for the accumulation of MIVE by the breast tumors. There was no statistically significant correlation between the MIBI and MIVE tumor uptake ratios. However, the latter correlate well with the presence of ER, as determined by an in vitro assay.MIVE scans add unique information concerning the tumor ER status in breast cancer patients, which could contribute to a better characterization of the tumor and aid in the selection of the most appropriate treatment protocol.

pH-responsive polymeric micelles (PM) consisting of random copolymers of N-isopropylacrylamide (NIPA), methacrylic acid (MAA), and octadecyl acrylate (ODA) were prepared and characterized. The critical aggregation concentration, as determined by a fluorescence probe technique, was approximately 10 mg/L in water and phosphate-buffered saline. Phase transition pH was estimated at 5.7. The decrease in pH was accompanied by the destruction of hydrophobic clusters. Micelle size was dependent on temperature and the nature of the aqueous medium. The micelles were successfully loaded with a substantial amount of a photoactive anticancer drug, namely, aluminum chloride phthalocyanine (AlClPc). pH-responsive PM loaded with AlClPc were found to exhibit higher cytotoxicity against EMT-6 mouse mammary cells in vitro than control Cremophor EL formulation. These results show the potential of poly(NIPA-co-MAA-co-ODA) for in vivo administration of water-insoluble, photosensitizing anticancer drugs.

Three new 125I-radioiodinated estrogens featuring a 13beta-ethyl instead of the natural 13beta-methyl group, i.e. 18-homoestradiols, were synthesized and evaluated as potential estrogen receptor imaging agents. The 16alpha-iodo-18-methylestradiol and the 125I-labeled analog were synthesized from the corresponding 16beta-bromo analog by the halogen-exchange method. The cis-bromohydrin precursor was obtained by bromination of an estrone enolacetate, followed by epimerization and reduction. The isomeric (17alpha,20E/Z)-iodovinyl-18-methylestradiols were prepared via the vinyltin intermediates. Treatment of 18-methyl-17alpha-ethynylestradiol with tri-n-butyltin hydride, in the presence of azobisisobutyronitrile as catalyst and heating at 90-100 degrees C afforded the (17alpha,20E)-tri-n-butylstannyl isomer as the major product. Changing the catalyst for triethyl borane, at room temperature, mainly gave the 20Z-isomer. The nca 125I-labeled analogs were obtained from their corresponding tin intermediates upon treatment with [125I]NaI in the presence of H2O2. The 16alpha-[125I]iodo- and isomeric (17alpha,20E/Z)-[125I]iodovinyl-18-methylestradiols were evaluated for estrogen receptor-mediated uterine uptake in immature female rats. Homologation of the C13-methyl group did improve the uterine uptake of the iodovinyl derivatives, but also increased blood retention, resulting in lower target uptake ratios. In the case of the 16alpha-iodo analog uterine retention decreased upon C13-homologation.

A brief summary of the mechanisms involved in photodynamic therapy (PDT) and the role of delivery vehicles for photosensitizer targeting is addressed. Phthalocyanines (Pc) have been coupled to adenovirus type 2 capsid proteins including the hexon, the penton base and the fiber to enhance their target selectivity. Adenovirus penton base proteins contain the arginine-glycine-aspartic acid peptidic sequence (RGD) motif known to bind with great affinity and high specificity to integrin receptors, expressed by several types of cancer. Tetrasulfonated aluminum phthalocyanine (AlPcS4) was covalently coupled to the various capsid proteins via one or two caproic acid spacer chains (A1 or A2) in 7:1 up to 66:1 molar ratios. The capacity of the bioconjugates for singlet oxygen production, as measured by an L-tryptophan oxidation assay, was strongly reduced, likely reflecting scavenging by the carrier. Cell adsorption and in vitro photocytotoxicity assays were carried out using the A549 and HEp2 human cell lines expressing integrin receptors, and one murine, the EMT-6 cell line, which lacks receptors for the RGD sequence. The AlPcS4A2-protein complexes induced greater cytotoxicity as compared to the analogous AlPcS4A1 preparations. The penton base-AlPcS4A2 derivative was the more phototoxic for all cell lines tested. Tumor response studies using Balb/c mice with EMT-6 tumor implants demonstrated that the free AlPcS4A2 induced complete tumor regression at a dose of 1 mumol/kg and 400 J/cm2, which is comparable to the activity of the known AlPcS2adj. A mixture of adenovirus type 2 soluble proteins covalently labeled with AlPcS4A2 required 0.5 mumol/kg to induce the same response with the same light dose, suggesting that the high affinity RGD/receptor complex is able to target Pc for PDT.

The biodistribution and dosimetry of the 20E and 20Z stereoisomers of 11 beta-methoxy-(17alpha,20)-[123I]iodovinylestradiol (MIVE) were evaluated in six healthy women. Tumor uptake and metabolism of the 20Z isomer were evaluated in 13 women referred after abnormal mammography or after discovery of a suspect mass at physical examination.The radiopharmaceuticals were prepared from their corresponding stannyl intermediates and administrated intravenously. Blood samples were drawn at different time intervals and urine was collected for up to 24 h. Metabolites were detected by radiochromatography. Tissue distribution was followed for up to 24 h by scintigraphic imaging. The dosimetry was computed according to the Medical Internal Radiation Dose scheme.The 20E and 20Z isomers exhibit similar biodistribution and dosimetry patterns. Chromatographic analysis of plasma samples of healthy volunteers and cancer patients, as well as in vitro plasma incubations, confirmed the in vivo stability of (20Z)-[123I]MIVE. Radioactivity was rapidly cleared from the blood by the liver and excreted through the gut, which received the highest radiation dose (0.211 mGy/MBq). The effective doses for the adult female and male phantom were 0.054 and 0.046 mSv/MBq, respectively. Among the 13 patients imaged with (20Z)-[123I]MIVE, 3 had fibrocystic disease with no focal uptake, 8 had good agreement with in vitro estrogen receptor determination and 2 were false-positive.The radiation dose after intravenous administration of 20E- or (20Z)-[123I]MIVE at imaging dose levels is within acceptable limits. There was a good correlation between uptake of (20Z)-[123I]MIVE and the presence of estrogen receptors in breast cancer patients.