Betulinic acid and its spray dried microparticle formulation: In vitro PDT effect against ovarian carcinoma cell line and in vivo plasma and tumor disposition.

The race against ovarian cancer continue to motivate the research worldwide. It is known that many antitumor drugs have limited penetration into solid tumor tissues due to its microenvironment, thus contributing to their low efficacy. Therapeutic modalities have been exploited to elicit antitumor effects based on microenvironment of tumor, including Photodynamic therapy (PDT). Prospection of natural small molecules and nanotechnology are important tools in the development of new ways of obtaining photoactive compounds that are biocompatible. The Betulinic acid (BA) has shown potential biological effect as bioactive drug, but it has low water solubility. Thus, in the present study, owing to the poor solubility of the BA, its free form (BAF) was compared to a spray dried microparticle betulinic acid/HP-ß-CD formulation (BAC) aiming to assess the BAF and BAC efficacy as a photosensitizer in PDT for application in ovarian cancer. BAF and BAC were submitted to assays in the presence of LED (λ = 420 nm) under different conditions (2.75 J/cm2, 5.5 J/cm2, and 11 J/cm2) and in absence of irradiation, after 5 min or 4 h of contact with ovarian carcinoma cells (A2780) or fibroblast murine cells (3T3). Furthermore, HPLC-MS/MS and MALDI-MSI methods were developed and validated in plasma and tumor of mice proving suitable for in vivo studies. The results found a greater photoinduced cytotoxic effect for the BAC at low concentration for A2780 when irradiated with LED with similar results for fluorescence microscopy. The results motivate us to continue the studies with the BA as a potential antitumor bioactive compound.

Pre-clinical compartmental pharmacokinetic modeling of 2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a (HPPH) as a photosensitizer in rat plasma by validated HPLC method.

A second-generation chlorin-based photosensitizer, 2-[1-hexyloxyethyl]-2-devinyl pyropheophorbide-a (HPPH) has shown tremendous therapeutic potential in clinical trials in the treatment of esophageal cancer. Herein, we have developed and validated a bioanalytical method for estimation of HPPH in rat plasma using High Performance Liquid Chromatography (HPLC) with a photo diode array (PDA) detector. The method was applied for carrying out pharmacokinetic study of HPPH. Further pharmacokinetic modeling was carried out to understand the compartment kinetics of HPPH. The developed method was fully validated as per the United States Food and Drug Administration (US-FDA) guidelines for bioanalytical method validation. The linearity of the method was in the range of 250-8000 ng mL-1, and the plasma recovery was found to be 70%. Pharmacokinetic parameters were evaluated and compared via non-compartment analysis and compartment modeling after the intravenous (i.v.) bolus administration in rats using Phoenix WinNonlin 8.0 (Certara™, USA). From the obtained results, we hypothesize that the HPPH complies with two compartmental pharmacokinetic model. Furthermore, it was observed that HPPH has the rapid distribution from the central compartment to peripheral compartment along with slow elimination from peripheral compartment.

[Determination of 8-methoxypsoralen in mouse plasma by high performance liquid chromatography and its application to pharmacokinetic study].

OBJECTIVE: To establish a high performance liquid chromatography (HPLC) method for the determination of 8-methoxypsoralen (8-MOP) in mouse plasma and apply it to a pharmacokinetic study of 8-MOP. METHODS: 8-MOP was separated on a Waters Symmetry18 column (250 mm × 4.6 mm, 5 µm) and determined by HPLC using isocratic elution, and 5-methoxypsoralen was used as internal standard. The mobile phase consisted of methanol-water (55:45, V/V) at a flow rate of 1.0 mL/min. The excitation and emission wavelength of fluorescence detector were set at 334 nm and 484 nm respectively, and the internal standard method was used for quantitative analysis. In the study, 60 healthy ICR male mice were randomly divided into twelve groups. The mice in control group were administered intragastrically with 1% Tween 80, and the mice in the other eleven groups were administered intragastrically with 8-MOP (40 mg/kg). Plasma concentrations of 8-MOP in the mice at different time points after treatment were determined by HPLC. Pharmacokinetic parameters were calculated by DAS 2.0 software. RESULTS: The calibration curve of 8-MOP was linear with a correlation coefficient of 0.999 3 over the concentration range of 0.05 to 10 mg/L, and the limit of detection was 0.015 mg/L. The average recoveries of 8? MOP at three different concentrations (0.10, 0.50, 2.5 mg/L) were from 92.5% to 100.6%. The intra-day precision of 8-MOP was from 3.3% to 8.2%, while the inter-day precision was from 3.4% to 6.7% at three spiked concentration levels. The extraction recoveries of 8-MOP were from 90.9% to 92.0%, and the plasma samples could be stored at -80°C for 15 days at least at three spiked concentration levels. 8-MOP could be detected in mouse plasma 5 min after intragastrical administration to the mice (1.4 mg/L). The concentration of 8-MOP in the mouse plasma reached a maximum 2 h after administration, and 8-MOP could still be detected 24 h after administration (1.1 mg/L). t1/2 was (39.21±3.65) h, Cmax was (2.31±0.02) mg/L, tmax was (2.00±0.00) h, and AUC0-t was (33.34±1.19) (h×mg)/L. CONCLUSION: The proposed method is accurate and simple,suitable for pharmacokinetics of 8-MOP in mice.

Development of a quantitative method for four photocyanine isomers using differential ion mobility and tandem mass spectrometry and its application in a preliminary pharmacokinetics investigation.

Photodynamic therapy (PDT) has been accepted as an alternative treatment for cancer, and its target specificity can be achieved by controlling the location at which light activates the photosensitizer. Photocyanine, a novel anticancer phthalocyanine-based photosensitizer, is a mixture of 4 cis-isomers of a series of synthetic products, and accordingly, it is essential to verify whether there are differences in pharmacokinetics among the four isomers for clinical application, which requires reliable analytical methods to measure the plasma concentrations of the four isomers. An efficient LC-MS/MS method coupled with differential mobility spectrometry (DMS) for the simultaneous quantification of the four photocyanine isomers in human plasma was developed and validated herein. This method had a limit of quantification of 10 ng mL-1 for each isomer and showed stable and reproducible inter- and intra-day results. Use of this method in preliminary pharmacokinetic studies in patients with esophageal cancer showed that the exposure and distribution of the four isomers were different, which had not been found in previous studies. The present research revealed that DMS was an effective tool for isomeric quantitation and that LC-DMS-MS/MS presented robust and reliable in biomatrix analysis. The method significantly improved peak separation and sensitivity compared with that of other LC-MS-based methods.

UHPLC-MS and MALDI-MS study of aluminum phthalocyanine chloride and development of a bioanalytical method for its quantification in nanoemulsions and biological matrices.

Metal phthalocyanines are promising components in photodynamic therapy. Aluminum phthalocyanine chloride (AlClPc) has been used to treat oral cancer in mice, human carious tissue, lung cancer cells and other conditions. To overcome the high hydrophobicity of AlClPc, phthalocyanine is often encapsulated in nanoformulations. Despite increased usage, little is known about the pharmacokinetics and biodistribution of AlClPc. The aim of this study was the development and validation of a UHPLC-MS method for the determination of AlClPc in solution after extraction from nanoformulations and biological matrices such as plasma and tissue. The described method has been assayed as to selectivity, linearity, limits of detection and quantification, precision and recovery. The present study is the first to describe the behavior of AlClPc in biological matrices with mass spectrometry as well as the first to describe the chromatographic behavior of AlClPc contaminants. Molecular mass analysis identified dechlorination of AlClPc by both LC/MS and MALDI-MS and an adduct formation in LC/MS. The parameters observed indicated that the method has applicability and robustness for use in biodistribution studies.

Macrophage selective photodynamic therapy by meta-tetra(hydroxyphenyl)chlorin loaded polymeric micelles: A possible treatment for cardiovascular diseases.

Selective elimination of macrophages by photodynamic therapy (PDT) is a new and promising therapeutic modality for the reduction of atherosclerotic plaques. m-Tetra(hydroxyphenyl)chlorin (mTHPC, or Temoporfin) may be suitable as photosensitizer for this application, as it is currently used in the clinic for cancer PDT. In the present study, mTHPC was encapsulated in polymeric micelles based on benzyl-poly(ε-caprolactone)-b-methoxy poly(ethylene glycol) (Ben-PCL-mPEG) using a film hydration method, with loading capacity of 17%. Because of higher lipase activity in RAW264.7 macrophages than in C166 endothelial cells, the former cells degraded the polymers faster, resulting in faster photosensitizer release and higher in vitro photocytotoxicity of mTHPC-loaded micelles in those macrophages. However, we observed release of mTHPC from the micelles in 30min in blood plasma in vitro which explains the observed similar in vivo pharmacokinetics of the mTHPC micellar formulation and free mTHPC. Therefore, we could not translate the beneficial macrophage selectivity from in vitro to in vivo. Nevertheless, we observed accumulation of mTHPC in atherosclerotic lesions of mice aorta's which is probably the result of binding to lipoproteins upon release from the micelles. Therefore, future experiments will be dedicated to increase the stability and thus allow accumulation of intact mTHPC-loaded Ben-PCL-mPEG micelles to macrophages of atherosclerotic lesions.

Evaluation of the Medicinal Potential of Two Ruthenium(II) Polypyridine Complexes as One- and Two-Photon Photodynamic Therapy Photosensitizers.

Two [Ru(phen)2 dppz]2+ derivatives (phen=1,10-phenantroline, dppz=dipyrido[3,2-a:2',3'-c]phenazine) with different functional groups on the dppz ligand [dppz-7,8-(OMe)2 (1), dppz-7,8-(OH)2 (2)] have been synthesized, characterized and investigated as photosensitizers (PSs) for photodynamic therapy (PDT) against cancer. Both complexes showed intense red phosphorescence and promising singlet oxygen (1 O2 ) quantum yields of 75 % (1) and 54 % (2) in acetonitrile. Complex 1 (logPo/w =-0.52, 2.4 nmol Ru per mg protein) was found to be more lipophilic, having also a higher cellular uptake efficiency compared to 2 (logPo/w =-0.20, 0.9 nmol Ru per mg protein). Complex 1 localized evenly in HeLa cells whereas 2, was mainly visualized in the cell membrane by confocal microscopy. In the dark, complex 1 (IC50 =36.5 µm) was found to be more toxic than complex 2 (IC50 >100 µm) on a HeLa cells monolayer. Importantly, in view of PDT applications, both complexes were found to be non-toxic in the dark towards multicellular HeLa spheroids (IC50 >100 µm). Upon one-photon irradiation (420 nm, 9.27 J cm-2 ), 1 exhibited higher phototoxicity (IC50 =3.1 µm) than 2 (IC50 =16.7 µm) on HeLa cell monolayers. When two-photon irradiation (800 nm, 9.90 J cm-2 ) was applied, only 1 (IC50 =9.5 µm) was found to be active toward HeLa spheroids. This study demonstrates that the functional group on the intercalative ligand has a strong influence on the cellular localization and anticancer activity of RuII polypyridyl complexes.

Evaluation of a general toxicity study incorporating phototoxicity assessments in Sprague-Dawley rats.

Previously, we showed that phototoxicity assessments in Sprague-Dawley (SD) rats can detect phototoxic potential to the same degree as those in guinea pigs. In this study, we examined whether phototoxicity assessments can be incorporated into general toxicology studies, using SD rats. Three phototoxic compounds were tested. Acridine and 8-methoxypsoralen (8-MOP) were transdermally administered, and 8-MOP and lomefloxacin were orally administered. The animals were allocated to three groups for each compound: single-dose, repeated-dose, and repeated-dose plus toxicokinetics (TK). The single-dose group was irradiated with UV-A and UV-B after a single administration of the drug. The repeated-dose and TK groups were irradiated after 8 days of repeated administration of the drug. Blood samples were also collected from the TK group on days 1 and 7 after administration. The phototoxic compounds resulted in skin reactions in all the groups, with no difference in the degree of skin reaction among the three groups. In the TK measurements, all of the phototoxic compounds were detected in the plasma samples, and the irradiation timing was close to the Tmax. These results indicate that phototoxic potential could be evaluated in the TK group, and phototoxicity assessments could be incorporated into general toxicology studies. This reduces the number of studies and animals required, thus shortening the research and development period, and supporting the 3Rs principle of animal experiments. The study also provides information regarding appropriate irradiation timings, differences between the sexes, and dose-response, in turn enabling the phototoxic risk of the compounds to be clearly evaluated.

A multi-functional nanoplatform for tumor synergistic phototherapy.

Phototherapy, which mainly includes photothermal treatment (PTT) and photodynamic treatment (PDT), is a photo-initiated, noninvasive and effective approach for cancer treatment. The high accumulation of photosensitizers (PSs) in a targeted tumor is still a major challenge for efficient light conversion, to generate reactive oxygen species (ROS) and local hyperthermia. In this study, a simple and efficient hyaluronic acid (HA)-modified nanoplatform (HA-TiO2@MWCNTs) with high tumor-targeting ability, excellent phototherapy efficiency, low light-associated side effects and good water solubility was developed. It could be an effective carrier to load hematoporphyrin monomethyl ether (HMME), owing to the tubular conjugate structure. Apart from this, the as-prepared TiO2@MWCNTs nanocomposites could also be used as PSs for tumor PTT and PDT. Those results in vitro and in vivo showed that the anti-tumor effect of this system-mediated PTT/PDT were significantly better than those of single treatment manner. In addition, this drug delivery system could realize high ratio of drug loading, sustained drug release, prolonged circulation in vivo and active targeted accumulation in tumor. These results suggest that HA-TiO2@MWCNTs/HMME has high potential for tumor synergistic phototherapy as a smart theranostic nanoplatform.

Pharmacokinetic and biodistribution study following systemic administration of Fospeg®--a Pegylated liposomal mTHPC formulation in a murine model.

Fospeg® is a newly developed photosensitizer formulation based on meso-tetra(hydroxyphenyl)chlorin (mTHPC), with hydrophilic liposomes to carry the hydrophobic photosensitizer to the target tissue. In this study the pharmacokinetics and biodistribution of Fospeg® were investigated by high performance liquid chromatography at various times (0.5-18 hours) following systemic i.v. administration. As a model an experimental HT29 colon tumor in NMRI nu/nu mice was employed. Our study indicates a higher plasma peak concentration, a longer circulation time and a better tumor-to-skin ratio than those of Foslip®, another liposomal mTHPC formulation. Data from ex vivo tissue fluorescence and reflectance imaging exhibit good correlation with chemical extraction. Our results have shown that optical imaging provides the potential for fluorophore quantification in biological tissues.

Pharmacokinetics of temoporfin-loaded liposome formulations: correlation of liposome and temoporfin blood concentration.

Liposomal formulations of the highly hydrophobic photosensitizer temoporfin were developed in order to overcome solubility-related problems associated with the current therapy scheme. We have incorporated temoporfin into liposomes of varying membrane composition, cholesterol content, and vesicle size. Specifically, two phosphatidyl oligoglycerols were compared to PEG2000-DSPE with respect to the ability to prolong circulation half life of the liposomal carrier. We measured the resulting pharmacokinetic profile of the liposomal carrier and the incorporated temoporfin in a rat model employing a radioactive lipid label and (14)C-temoporfin. The data for the removal of liposomes and temoporfin were analyzed in terms of classical pharmacokinetic theory assuming a two-compartment model. This model, however, does not allow in a straightforward manner to distinguish between temoporfin eliminated together with the liposomal carrier and temoporfin that is first transferred to other blood components (e. g. plasma proteins) before being eliminated from the blood. We therefore additionally analyzed the data based on two separate one-compartment models for the liposomes and temoporfin. The model yields the ratio of the rate constant of temoporfin elimination together with the liposomal carrier and the rate constant of temoporfin elimination following the transfer to e. g. plasma proteins. Our analysis using this model demonstrates that a fraction of temoporfin is released from the liposomes prior to being eliminated from the blood. In case of unmodified liposomes this temoporfin release was observed to increase with decreasing bilayer fluidity, indicating an accelerated temoporfin transfer from gel-phase liposomes to e. g. plasma proteins. Interestingly, liposomes carrying either one of the three investigated surface-modifying agents did not adhere to the tendencies observed for unmodified liposomes. Although surface-modified liposomes exhibited improved pharmacokinetic properties with regard to the liposomal carrier, an enhanced temoporfin loss and elimination from the PEGylated-liposomes was observed. This effect was more pronounced for PEGylated liposomes than for the two oligo-glycerols. Our combined experimental-theoretical approach for in vivo plasma re-distribution of liposomal drugs may help to optimize colloidal drug carrier systems.

Quantification of the plasma clearance kinetics of a gadolinium-based contrast agent by photoinduced triplet harvesting.

The use of gadolinium-based contrast agents (GBCA) is integral to the field of diagnostic magnetic resonance imaging (MRI). Pharmacokinetic evaluation of the plasma clearance of GBCA is required for all new agents or improved formulations, to address concerns over toxicity or unforeseen side effects. Current methods to measure GBCA in plasma lack either a rapid readout or the sensitivity to measure small samples or require extensive processing of plasma, all obstacles in the development and characterization of new GBCA. Here, we quantify the plasma concentration of a labeled analogue of a common clinical GBCA by ligand triplet harvesting and energy transfer. The nonemittive GBCA becomes a "dark donor" to a fluorescent detector molecule, with a lower limit of detection of 10(-7) M in unprocessed plasma. On a time scale of minutes, we determine the plasma clearance rate in the wild-type mouse, using time-resolved fluorescence on a standard laboratory plate reader.

Glycodendrimeric phenylporphyrins as new candidates for retinoblastoma PDT: blood carriers and photodynamic activity in cells.

Photodynamic therapy (PDT) has recently been proposed as a possible indication in the conservative treatment of hereditary retinoblastoma. In order to create photosensitizers with enhanced targeting ability toward retinoblastoma cells, meso-tetraphenylporphyrins bearing one glycodendrimeric moiety have been synthesized. The binding properties to plasma proteins and photodynamic activity of two monodendrimeric porphyrins bearing three mannose units via monoethylene glycol (1) or diethylene glycol (2) linkers have been compared to that of the non-dendrimeric tri-substituted derivative [TPP(p-Deg-O-α-ManOH)(3)]. The dendrimeric structure was found to highly increase the binding affinity to plasma proteins and to modify to some extent plasma distribution. HDL and to a lesser extent LDL have been shown to be the main carriers of dendrimeric and non-dendrimeric compounds. The phototoxicity observed for the two glycodendrimers (1) and (2) (LD(50)=0.5 µM) in Y79 cells is of the same order of magnitude that for TPP(p-Deg-O-α-ManOH)(3) (LD(50)=0.7 µM), with a similar cellular uptake level for (1) and a lower for (2). A serum content increase from 2% to 20% (v/v) in the incubation medium was found to inhibit both cellular uptake and photoactivity of dendrimeric derivatives, whereas those of TPP(p-Deg-O-α-ManOH)(3) remained little affected. Specificities of glycodendrimeric porphyrins, combining a lower cellular uptake together with a higher affinity toward plasma proteins, make these derivatives possible candidates for a vascular targeting PDT.

Biodistribution and pharmacokinetic studies of a porphyrin dimer photosensitizer (Oxdime) by fluorescence imaging and spectroscopy in mice bearing xenograft tumors.

Herein, we present a study of the pharmacokinetics and biodistribution of a butadiyne-linked conjugated porphyrin dimer (Oxdime) designed to have high near-infrared (NIR) 2-photon absorption cross-section for photodynamic therapy (PDT). Changes in biodistribution over time were monitored in mice carrying B16-F10 melanoma xenografts, following intravenous injection. Using fluorescence imaging of live animals and analyzing isolated organs ex vivo at different time points between 30 min and 24 h after injection, accumulation of Oxdime was measured in several organs (heart, kidney and liver) and in tumor. The concentration in the plasma was about 5-10 times higher than in other tissues. The fluorescence signal peaked at 3-12 h after injection in most tissues, including the tumor and the plasma. The change in the fluorescence emission spectrum of the sensitizer over time was also monitored and a shift in the maximum from 800 to 740 nm was observed over 24 h, showing that the Oxdime is metabolized. Significant quantities accumulated in the tumor, indicating that this PDT sensitizer may be promising for cancer treatment.

Interaction of liposomal formulations of meta-tetra(hydroxyphenyl)chlorin (temoporfin) with serum proteins: protein binding and liposome destruction.

mTHPC is a non polar photosensitizer used in photodynamic therapy. To improve its solubility and pharmacokinetic properties, liposomes were proposed as drug carriers. Binding of liposomal mTHPC to serum proteins and stability of drug carriers in serum are of major importance for PDT efficacy; however, neither was reported before. We studied drug binding to human serum proteins using size-exclusion chromatography. Liposomes destruction in human serum was measured by nanoparticle tracking analysis (NTA). Inclusion of mTHPC into conventional (Foslip(®)) and PEGylated (Fospeg(®)) liposomes does not affect equilibrium serum protein binding compared with solvent-based mTHPC. At short incubation times the redistribution of mTHPC from Foslip(®) and Fospeg(®) proceeds by both drug release and liposomes destruction. At longer incubation times, the drug redistributes only by release. The release of mTHPC from PEGylated vesicles is delayed compared with conventional liposomes, alongside with greatly decreased liposomes destruction. Thus, for long-circulation times the pharmacokinetic behavior of Fospeg(®) could be influenced by a combination of protein- and liposome-bound drug. The study highlights the modes of interaction of photosensitizer-loaded nanovesicles in serum to predict optimal drug delivery and behavior in vivo in preclinical models, as well as the novel application of NTA to assess the destruction of liposomes.

Glutathione S-transferase genotype is associated with sensitivity to psoralen-ultraviolet A photochemotherapy.

BACKGROUND: There is marked interpatient variation in responses to psoralen-ultraviolet A (PUVA) photochemotherapy. Identification of molecular biomarkers of PUVA sensitivity may facilitate treatment predictability.The glutathione S-transferases (GSTs) influence cutaneous defence against UV radiation-induced oxidative stress and are therefore candidate biomarkers of PUVA sensitivity. Several human GSTs, including GSTM1 and GSTT1, are polymorphic, and null polymorphisms have been associated with increased UVB erythemal sensitivity and skin cancer risk. PUVA also increases skin cancer risk. OBJECTIVES: To investigate the effect of GST genotype on PUVA sensitivity. METHODS: We investigated GST genotype in patients starting PUVA (n=111) and the effects of 8-methoxypsoralen (8-MOP) on antioxidant response element (ARE)-regulated gene expression in mammalian cells. RESULTS: Lower minimal phototoxic doses (MPD) (P=0·022) and higher serum 8-MOP concentrations (P=0·052) were seen in GSTM1-null allele homozygotes compared with patients with one or two active alleles. In a subset of patients with psoriasis (n=50), the GSTM1 genotype was not associated with PUVA outcomes, although MPD [hazard ratio (HR) 1·37; 95% confidence interval (CI) for HR 1·15-1·64] and GSTT1-null (HR 2·39; 95% CI for HR 1·31-4·35) and GSTP1b (HR 1·96; 95% CI for HR 1·10-3·51) genotypes were associated with clearance of psoriasis in this patient group. Exposure of mammalian cells to 8-MOP induced gene expression via the ARE, a regulatory sequence in promoters of cytoprotective genes including GSTs, suggesting that these genes may be implicated in 8-MOP metabolism. CONCLUSION: The polymorphic human GSTs are associated with PUVA sensitivity. Further studies are required to examine the clinical relevance of these preliminary findings.

Improved in vivo delivery of m-THPC via pegylated liposomes for use in photodynamic therapy.

Pegylated liposomal nanocarriers have been developed with the aim of achieving improved uptake of the clinical PDT photosensitiser, m-THPC, into target tissues through increased circulation time and bioavailability. This study investigates the biodistribution and PDT efficacy of m-THPC in its standard formulation (Foscan®) compared to m-THPC incorporated in liposomes with different degrees of pegylation (FosPEG 2% and FosPEG 8%), following i.v. administration to normal and tumour bearing rats. The plasma pharmacokinetics were described using a three compartmental analysis and gave elimination half lives of 90 h, 99 h and 138 h for Foscan®, FosPEG 2% and 8% respectively. The accumulation of m-THPC in tumour and normal tissues, including skin, showed that maximal tumour to skin ratios were observed at ≤ 24 h with FosPEG 2% and 8%, whilst skin photosensitivity studies showed Foscan® induces more damage compared to the liposomes at drug-light intervals of 96 and 168 h. PDT treatment at 24h post-administration (0.05 mg kg⁻¹) showed higher tumour necrosis using pegylated liposomal formulations in comparison to Foscan®, which is attributed to the higher tumour uptake and blood plasma concentrations. Clinically, this improved selectivity has the potential to reduce not only normal tissue damage, but the drug dose required and cutaneous photosensitivity.

Characterization of cutaneous photosensitivity in healthy volunteers receiving talaporfin sodium.

PURPOSE: Historically, cutaneous photosensitivity has been the most common side effect of treatment with light-activated drugs. Talaporfin sodium is a water soluble photosensitizer in commercial use and clinical development that is cleared from the body relatively rapidly. This trial was conducted to determine the period of skin photosensitivity in healthy subjects given talaporfin sodium and to determine the correlation between photosensitivity and plasma levels of talaporfin sodium. METHODS: Twenty healthy volunteers were dosed with 0.25-1.0mg/kg talaporfin sodium and exposed at successive timepoints to a solar simulator applied to a small patch of skin on the back. Photosensitivity was assessed at these sites 24h later. Duration of photosensitivity and correlation with plasma drug concentration were analyzed. RESULTS: Skin reactions were generally mild and were classified most commonly as asymptomatic erythema. Photosensitivity subsided in each subject between 1 and 3 weeks after dosing. Subjects no longer exhibited photosensitivity at plasma drug levels between 600 and 2900ng/ml in each subject. Two subjects in the lowest dose group did not exhibit photosensitivity despite plasma drug levels as high as 4000ng/ml. CONCLUSIONS: These results indicate that a clinically effective dose of talaporfin sodium was well-tolerated and that cutaneous photosensitivity was mild and resolved relatively rapidly.

Enhancement of blood porphyrin emission intensity with aminolevulinic acid administration: a new concept for photodynamic diagnosis of early prostate cancer.

BACKGROUND: The objective of this paper was to verify if the oral administration of δ-aminolevulinic acid (ALA) in animals with prostate tumor can increase the sensitivity of cancer diagnosis by protoporphyrin IX blood autofluorescence. In this study, the autofluorescence of blood porphyrin was analyzed using fluorescence spectroscopy on healthy male NUDE mice and in those with prostate cancer induced by the inoculation of DU145 cells. METHODS: A total of 18 male NUDE mice, ∼8 weeks old on arrival were divided into 3 groups: Control, Tumor and ALA Tumor. The autofluorescence of blood porphyrin of the groups was analyzed using fluorescence spectroscopy at different days after tumor induction, to monitor the tumor progression. Emission spectra were obtained by exciting the samples at 405 nm. The animals inoculated had their blood collected with and without oral ALA solution administration to compare PPIX endogenous (Tumor group) and exogenous (ALA Tumor group) signal intensity and to establish a method to diagnosis early prostate cancer. RESULTS: Significant differences were observed in autofluorescence intensities measured in the 575-725 nm spectral regions for the studied groups. CONCLUSIONS: The results showed an enhancement of almost 100% in blood PPIX fluorescence, using the oral administration of δ-aminolevulinic acid on male NUDE mice with prostate cancer, making fluorescence measurements more accurate and sensitive since the first week after tumor induction.

Study on the interaction between hematoporphyrin monomethyl ether and DNA and the determination of hematoporphyrin monomethyl ether using the resonance light scattering technique.

The interaction between photosensitizer anticancer drug hematoporphyrin monomethyl ether (HMME) and ctDNA has been studied based on the decreased resonance light scattering (RLS) phenomenon. The RLS, UV-vis and fluorescence spectra characteristics of the HMME-ctDNA system were investigated. Besides, the phosphodiesters quaternary ammonium salt (PQAS), a kind of new gemini surfactant synthesized recently, was used to determine anticancer drug HMME based on the increasing RLS intensity. Under the optimum assay conditions, the enhanced RLS intensity was proportional to the concentration of HMME. The linear range was 0.8-8.4microgmL(-1), with correlation coefficient R(2)=0.9913. The detection limit was 0.014microgmL(-1). The human serum samples and urine samples were determined satisfactorily, which proved that this method was reliable and applicable in the determination of HMME in body fluid. The presented method was simple, sensitive and straightforward and could be a significant method in clinical analysis.