Preparation of Hematoporphyrin-Poly(Lactic Acid) Nanoparticles Encapsulated Perfluoropentane/Salicylic Acid for Enhanced US/CEST MR Bimodal Imaging.

Background: Medical imaging modalities, such as magnetic resonance imaging (MRI), ultrasound, and fluorescence imaging, have gained widespread acceptance in clinical practice for tumor diagnosis. Each imaging modality has its own unique principles, advantages, and limitations, thus necessitating a multimodal approach for a comprehensive disease understanding of the disease process. To enhance diagnostic precision, physicians frequently integrate data from multiple imaging modalities, driving research advancements in multimodal imaging technology research. Methods: In this study, hematoporphyrin-poly (lactic acid) (HP-PLLA) polymer was prepared via ring-opening polymerization and thoroughly characterized using FT-IR, 1H-NMR, XRD, and TGA. HP-PLLA based nanoparticles encapsulating perfluoropentane (PFP) and salicylic acid were prepared via emulsion-solvent evaporation. Zeta potential and mean diameter were assessed using DLS and TEM. Biocompatibility was evaluated via cell migration, hemolysis, and cytotoxicity assays. Ultrasonic imaging was performed with a dedicated apparatus, while CEST MRI was conducted using a 7.0 T animal scanner. Results: We designed and prepared a novel dual-mode nanoimaging probe SA/PFP@HP-PLLA NPs. PFP enhanced US imaging, while salicylic acid bolstered CEST imaging. With an average size of 74.43 ± 1.12 nm, a polydispersity index of 0.175 ± 0.015, and a surface zeta potential of -64.1 ± 2.11 mV. These NPs exhibit excellent biocompatibility and stability. Both in vitro and in vivo experiments confirmed the SA/PFP@HP-PLLA NP's ability to improve tumor characterization and diagnostic precision. Conclusion: The SA/PFP@HP-PLLA NPs demonstrate promising dual-modality imaging capabilities, indicating their potential for preclinical and clinical use as a contrast agent.

Positron emission tomography guided synergistic treatment of melanoma using multifunctional zirconium-hematoporphyrin nanosonosensitizers.

Sonodynamic therapy (SDT) has emerged as a useful approach for tumor treatment. However, its widespread application is impeded by poor pharmacokinetics of existing sonosensitizers. Here we developed a metal-organic nanoplatform, wherein a small-molecule sonosensitizer (hematoporphyrin monomethyl ether, HMME) was ingeniously coordinated with zirconium, resulting in a multifunctional nanosonosensitizer termed Zr-HMME. Through post-synthetic modifications involving PEGylation and tumor-targeting peptide (F3) linkage, a nanoplatform capable of homing on melanoma was produced, which could elicit robust immune responses to suppress tumor lung metastasis in the host organism. Importantly, after seamless incorporation of positron-emitting 89Zr into this nanosonosensitizer, positron emission tomography (PET) could be used to monitor its in vivo pharmacokinetics. PET imaging studies revealed that this nanoplatform exhibited potent tumor accumulation and strong in vivo stability. Using intrinsic fluorescence from HMME, a dual-modal diagnostic capability (fluorescence and PET) was confirmed for this nanosonosensitizer. In addition, the mechanisms of how this nanoplatform interacted with immune system were also investigated. The collective data proved that the coordination structure between small-molecule drug cargos and metals may enhance the functions of each other while mitigating their weaknesses. This straightforward approach can expand the potential applications of suitable drug molecules.

Study of pharmacokinetics and cutaneous photosensitization of hemoporfin in healthy volunteers.

BACKGROUND: Hemoporfin is a porphyrin-based photosensitizer and has been used for photodynamic therapy of port wine stain birthmarks in China. This study assessed the pharmacokinetics and cutaneous photosensitization of Hemoporfin in healthy volunteers. METHODS: Sixteen healthy subjects received a single intravenous infusion injection of Hemoporfin (5 mg/kg). The concentrations of Hemoporfin (MHD) and its metabolite Haematoporphyrin (HP) in plasma, urine and faeces were determined. The pharmacokinetic parameters were calculated. In addition, the cutaneous photosensitization was evaluated under the irradiation of solar simulator, 532 nm laser, and sunlight. RESULTS: The Cmax of MHD and HP were 46.7 ± 8.41 and 1.04 ± 0.265 µg/ml, respectively. The t1/2 of MHD and HP were 5.09 ± 0.945 and 5.71 ± 2.65 h, respectively. The AUC0-24h of MHD and HP were 29.8 ± 6.19 and 0.757 ± 0.285 h·µg/ml, respectively. The AUC0-∞ of MHD and HP were 29.8 ± 6.2 and 0.792 ± 0.308 h·µg/ml, respectively. The cumulative fecal excretion rate of MHD and HP were 45.3% and 1.05% at 96 h, respectively. Whereas, the cumulative urinary excretion rate of MHD was only 0.132% at 96 h. The concentration of HP in urine was less than 10% of MHD. After 52 h of administration, the cutaneous photosensitization associated with the exposure to various light sources was minimal. CONCLUSION: MHD and HP were excreted mainly through the faeces after intravenous infusion. Hemoporfin associated cutaneous photosensitization was insignificant.

pH-sensitive metal-phenolic network capsules for targeted photodynamic therapy against cancer cells.

Photodynamic therapy (PDT) is an effective and promising method for cancer treatment, which is proposed for more than one century. However, the specific delivery of photosensitizer to target carcinoma cells to reduce the side effect is still a great challenge. This work provides a strategy to deliver photosensitizers to cancer cells by utilizing pH-sensitive polyethylene glycol metal-phenolic network (PEG-MPN) capsules to encapsulate haematoporphyrin monomethyl ether (HMME). With the assistance of folic acid (FA), HMME-doped PEG-MPN capsules (MPN@HMMEs) accumulate in carcinoma cells selectively followed by releasing HMME in the lysosomes because of the physiologically relevant acidic pH environment. From the fluorescent ratiometric sensing and reactive oxygen species (ROS) regionality distribution of MPN@HMMEs, we demonstrated the encapsulated photosensitizers are diffused from lysosomes to cytoplasm. Under irradiation at 638 nm laser, ROS generated from the photosensitizers induced cancer cells undergoing apoptosis while normal cells survive. Therefore, MPN@HMME could be applied as a new strategy for targeted PDT against cancer and PEG-MPN capsules are expected to be general carries for drug delivering.

HematoPorphyrin Monomethyl Ether polymer contrast agent for ultrasound/photoacoustic dual-modality imaging-guided synergistic high intensity focused ultrasound (HIFU) therapy.

This study is to prepare a hematoporphyrin monomethyl ether (HMME)-loaded poly(lactic-co-glycolic acid) (PLGA) microcapsules (HMME/PLGA), which could not only function as efficient contrast agent for ultrasound (US)/photoacoustic (PA) imaging, but also as a synergistic agent for high intensity focused ultrasound (HIFU) ablation. Sonosensitizer HMME nanoparticles were integrated into PLGA microcapsules with the double emulsion evaporation method. After characterization, the cell-killing and cell proliferation-inhibiting effects of HMME/PLGA microcapsules on ovarian cancer SKOV3 cells were assessed. The US/PA imaging-enhancing effects and synergistic effects on HIFU were evaluated both in vitro and in vivo. HMME/PLGA microcapsules were highly dispersed with well-defined spherical morphology (357 ± 0.72 nm in diameter, PDI = 0.932). Encapsulation efficiency and drug-loading efficiency were 58.33 ± 0.95% and 4.73 ± 0.15%, respectively. The HMME/PLGA microcapsules remarkably killed the SKOV3 cells and inhibited the cell proliferation, significantly enhanced the US/PA imaging results and greatly enhanced the HIFU ablation effects on ovarian cancer in nude mice by the HMME-mediated sono-dynamic chemistry therapy (SDT). HMME/PLGA microcapsules represent a potential multifunctional contrast agent for HIFU diagnosis and treatment, which might provide a novel strategy for the highly efficient imaging-guided non-invasive HIFU synergistic therapy for cancers by SDT in clinic.

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.

Undifferentiated Neuroblastoma Cells Are More Sensitive to Photogenerated Oxidative Stress Than Differentiated Cells.

Neuroblastoma is one of the most aggressive cancers and has a complex form of differentiation. We hypothesized that advanced cellular differentiation may alter the susceptibility of neuroblastoma to photodynamic treatment (PDT) and confer selective survival advantage. We demonstrated that hematoporphyrin uptake by undifferentiated SH-SY5Y cells was lower than that of differentiated counterparts, yet the former were more susceptible to PDT-induced oxidative stress killing. Photogenerated reactive oxygen species (ROS) in undifferentiated cells efficiently stimulated cell cycle arrest at G2/M phase, mitochondrial apoptotic pathway activation, the sustained phosphorylation of Akt/GSK-3ß and ERK. Differentiated cells with more resistance to PDT exhibited a ROS-independent and a prolonged activation of ERK. Both SH-SY5Y cells exposed to PDT exhibited ROS-independent p38 and JNK activation. These results may have important implications for neuroblastoma patients undergoing photodynamic therapy.

The application of hyaluronic acid-derivatized carbon nanotubes in hematoporphyrin monomethyl ether-based photodynamic therapy for in vivo and in vitro cancer treatment.

Carbon nanotubes (CNTs) have shown great potential in both photothermal therapy and drug delivery. In this study, a CNT derivative, hyaluronic acid-derivatized CNTs (HA-CNTs) with high aqueous solubility, neutral pH, and tumor-targeting activity, were synthesized and characterized, and then a new photodynamic therapy agent, hematoporphyrin monomethyl ether (HMME), was adsorbed onto the functionalized CNTs to develop HMME-HA-CNTs. Tumor growth inhibition was investigated both in vivo and in vitro by a combination of photothermal therapy and photodynamic therapy using HMME-HA-CNTs. The ability of HMME-HA-CNT nanoparticles to combine local specific photodynamic therapy with external near-infrared photothermal therapy significantly improved the therapeutic efficacy of cancer treatment. Compared with photodynamic therapy or photothermal therapy alone, the combined treatment demonstrated a synergistic effect, resulting in higher therapeutic efficacy without obvious toxic effects to normal organs. Overall, it was demonstrated that HMME-HA-CNTs could be successfully applied to photodynamic therapy and photothermal therapy simultaneously in future tumor therapy.

Apoptosis of U937 cells induced by hematoporphyrin monomethyl ether-mediated sonodynamic action.

PURPOSE: The present study aims to investigate apoptosis of U937 cells induced by hematoporphyrin monomethyl ether (HMME)-mediated sonodynamic therapy (SDT). MATERIALS: HMME concentration was kept constant at 10 µg/mL. Tumor cells suspended in serum-free RPM1640 were exposed to ultrasound at 1.1 MHz for up to 60 seconds with an intensity of 1 W/cm(2) in the presence and absence of HMME. The viability of cells was determined by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltertrazolium bromide tetrazolium (MTT) test. Apoptosis was analyzed using a flow cytometer with Annexin V-PE/7-ADD staining as well as fluorescence microscopy with 4'-6-diamidino-2-phenylindole (DAPI) staining. The DNA damage of U937 cells, intracellular reactive oxygen species (ROS), and mitochondria membrane potential (MMP) were also analyzed by a flow cytometer after exposures. Western blotting and reverse transcriptase-polymerase chain reaction were used to analyze the protein and mRNA expression level of caspase-3 and poly(ADP-ribose) polymerase (PARP). RESULTS: Fluorescent imaging revealed that HMME mainly localized in the mitochondria. MTT assay showed 55.6% of cell survival at 4 hours post-SDT. Flow cytometric analysis displayed a significant increase in the early- and late-apoptotic cell populations (35.6%) of U937 cells by HMME-mediated SDT. Compared with the control, ultrasound-alone, and HMME-alone groups, the intracellular ROS and the MMP loss were greatly increased in the combined SDT group. Obvious nuclear condensation was also found with DAPI staining, and the DNA fragment increased to 33.9% at 2 hours post-SDT treatment. Immunofluorescent staining indicated obvious Bax translocation after SDT. Western blot showed visible enhancement of caspase-3 and PARP cleavage. In addition, caspase-3 and PARP mRNA expression of U937 cells increased remarkably after SDT treatment. CONCLUSIONS: The findings demonstrated that HMME-mediated sonodynamic action (HMME-SDT) significantly induced apoptosis of U937 cells, suggesting that HMME may be a good sonosensitizer, and HMME-SDT might be a potential therapeutic strategy for cancer treatment.

Research progress of Hemoporfin--part one: preclinical study.

The second generation photosensitizer Hemoporfin (7(12)-(1-methoxyethyl) -12(7)-(1-hydroxyethyl)-3,8,13,17-tetramethyl-21H,23H-porphin-2,18-dipropionic acid) is a porphyrin derivative which processes a stable structure, high singlet oxygen yield, high photoactivity, low dark toxicity and fast clearance rate. Hemoporfin, also known as hematoporphyrin monomethyl ether (HMME) has been studied and used in photodynamic therapy (PDT) in China since 1989. This series of reports will provide an overview on the preclinical and clinical studies of this PDT photosensitizer. The first part of this series will highlight the results of preclinical studies that focused on the compound's optical characteristics, mechanism of the activities, pharmacological and toxicological properties.

Synthesis, radiolabeling, biodistribution and fluorescent imaging of histidine-coupled hematoporphyrin.

INTRODUCTION: Hematoporphyrin (Hp) and hematoporphyrin derivatives (HpDs) have been widely used as photosensitizers in photodynamic therapy (PDT). Radiolabeling of HpDs is helpful for preclinical and clinical studies of PDT. METHODS: The histidine-coupled hematoporphyrin (His-Hp) was synthesized and radiolabeled with [(99m)Tc(CO)(3)(H(2)O)(3)](+). Biodistribution of the radioligand and fluorescent imaging of His-Hp in mice bearing S180 tumor were investigated. RESULTS: [(99m)Tc(CO)(3)](+)-labeled His-Hp was electrically neutral, hydrophilic and stable. The biodistribution of the radioligand in S180 tumor-bearing mice was similar with that of nonlabeled HpD in the literature. The uptake of His-Hp in tumors and livers was confirmed by fluorescent imaging. CONCLUSIONS: The complex [(99m)Tc(CO)(3)](+)-His-Hp might be suitable for in vivo dose evaluation of HpD in PDT.

Tolerance and pharmacokinetics of single-dose intravenous hemoporfin in healthy volunteers.

AIM: To investigate the safety, tolerability and pharmacokinetics of intravenous hemoporfin, a novel photosensitive drug for the treatment of port-wine stain (PWS), in healthy Chinese volunteers following single-dose administration. METHODS: Thirty-six healthy Chinese subjects were enrolled. The subjects were administered hemoporfin (2.5, 5, 7.5 or 10 mg/kg) via single-dose intravenous infusion. Pharmacokinetics of the drug were studied in the groups with doses of 2.5, 5 and 7.5 mg/kg, and tolerability was studied in all the 4 groups. Safety and tolerance were evaluated by monitoring adverse events and laboratory parameters, and pharmacokinetics were assessed by determining hemoporfin content with a validated high-performance liquid chromatography with fluorescence detection (HPLC/FLD) method. RESULTS: Mild and transient adverse events occurred in the trial (n=10), but none were serious, and no subjects were withdrawn from the trial. The gastrointestinal tract adverse events, such as nausea, stomach upset, abdominal pain and vomiting, were observed in the groups with doses of 7.5 and 10 mg/kg. Increased alanine aminotransferase (ALT) concentration was found in 3 subjects, and increased alkaline phosphatase (ALP) concentration in one subject. The half-life of hemoporfin for doses of 2.5, 5, and 7.5 mg/kg was 1.26 h, 1.31 h, and 1.70 h, respectively. C(max) and AUC increased with dose for intravenous single-dose administration of hemoporfin in the 2.5, 5, and 7.5 mg/kg groups. Urinary excretion of hemoporfin within 12 h was less than 0.2%. CONCLUSION: Hemoporfin is safe and well-tolerated in healthy Chinese volunteers at a single intravenous dose of up to 10 mg/kg. It was rapidly cleared from the blood and had a short half-life, which insures a short light-avoidance period.

In vitro and in vivo targeted delivery of photosensitizers to the tumor cells for enhanced photodynamic effects.

BACKGROUND: Efficacy of photodynamic therapy can be enhanced by improving uptake, localization, and sub-cellular localization of sensitizers at the sensitive targets. MATERIALS AND METHODS: Uptake, localization, and photodynamic effects of hematoporphyrin derivative (HpD, Photosan-3; PS-3) and disulfonated aluminum phthalocyanine (AlPcS2) were studied either encapsulated in liposomes or conjugated to a monoclonal antibody to carcinoembryonic antigen (anti-CEA) in a brain glioma cell line, BMG-1. RESULTS: Although the total uptake with encapsulated or conjugated sensitizers was less than the free sensitizers, photodynamic efficiency was higher due to the localization of the sensitizer at the sensitive targets. Biodistribution of intravenously administered technetium (99m Tc)-labeled PS-3 analyzed by gamma camera imaging showed maximum accumulation in the liver followed by tumor. Tumor/muscle (T/N) ratio of free PS-3 was higher compared to encapsulated or conjugated PS-3 but the accumulation of PS-3 significantly reduced in brain and cutaneous tissue following modulated delivery. Pharmacokinetics suggested faster accumulation of encapsulated and conjugated PS-3 in the tumor. CONCLUSION: Localization of sensitizers at sensitive targets and reduced accumulation in normal tissues with liposome encapsulation and antibody conjugation suggest that these two delivery systems can potentially enhance the efficacy of photodynamic treatment.

Non-homogeneous liver distribution of photosensitizer and its consequence for photodynamic therapy outcome.

BACKGROUND: Photodynamic therapy is mainly used for treatment of malignant lesions, and is based on selective location of a photosensitizer in the tumor tissue, followed by light at wavelengths matching the photosensitizer absorption spectrum. In molecular oxygen presence, reactive oxygen species are generated, inducing cells to die. One of the limitations of photodynamic therapy is the variability of photosensitizer concentration observed in systemically photosensitized tissues, mainly due to differences of the tissue architecture, cell lines, and pharmacokinetics. This study aim was to demonstrate the spatial distribution of a hematoporphyrin derivative, Photogem, in the healthy liver tissue of Wistar rats via fluorescence spectroscopy, and to understand its implications on photodynamic response. METHODS: Fifteen male Wistar rats were intravenously photosensitized with 1.5mg/kg body weight of Photogem. Laser-induced fluorescence spectroscopy at 532 nm-excitation was performed on ex vivo liver slices. The influence of photosensitizer surface distribution detected by fluorescence and the induced depth of necrosis were investigated in five animals. RESULTS: Photosensitizer distribution on rat liver showed to be greatly non-homogeneous. This may affect photodynamic therapy response as shown in the results of depth of necrosis. CONCLUSIONS: As a consequence of these results, this study suggests that photosensitizer surface spatial distribution should be taken into account in photodynamic therapy dosimetry, as this will help to better predict clinical results.

Differences in sensitivity to HMME-mediated photodynamic therapy between EBV+ C666-1 and EBV- CNE2 cells.

OBJECTIVES: The aim of this study was to compare the sensitivity of hematoporphyrin monomethyl ether (HMME)-mediated PDT in the Epstein-Barr virus (EBV) positive and negative human nasopharyngeal carcinoma (NPC) cells. METHODS AND MATERIALS: The intracellular uptake of HMME in C666-1 (EBV+) and CNE2 (EBV-) cells was quantitatively determined after incubating with different concentration of HMME. The subcellular localization of HMME was examined under a laser scanning fluorescence microscopy. The survival rate of C666-1 and CNE2 cells after HMME PDT was evaluated with clonogenic assay. RESULTS: The EBV- CNE2 cells showed higher intracellular uptake of HMME and lower survival rate than EBV+ C666-1 cells. There was no significant difference in terms of subcellular localization of HMME between C666-1 and CNE2 cells. CONCLUSION: The sensitivity of EBV- CNE2 cells to HMME-mediated PDT was significantly higher than that of EBV+ C666-1 cells. The intracellular uptake of HMME plays a key role in determining the PDT sensitivity.

Evaluation of in vivo biological activities of tetrapyrrole ethanolamides as novel anticancer agents.

The tetrapyrrole ethanolamide derivatives, hematoporphyrin propylether ethanolamide (HPPEEA, 1) and pheophorbide a ethanolamide (PEA, 2) have previously shown some photodynamic activities in an in vitro photodynamic assay (D. Girard et al. Bioorg. Med. Chem. Lett. 18 (2008) 360-365). Extending this study to an in vivo one, HPPEEA and PEA were evaluated for their anticancer, toxicity, and pharmacokinetic activities in mouse animal models. The compounds showed moderate anticancer activity without apparent acute toxicity and without secondary tumour development. This indicates noteworthy anti-metastasis activity. The pharmacokinetic study revealed the compound fast clearances from body tissues. This is an important therapeutic concern since these compounds are light sensitive. Thus, the combination of photodynamic and anti-metastasis activities with fast tissue clearance indicates that HPPEEA and PEA are good candidates for further photodynamic treatment evaluations.

Cell death and intracellular distribution of hematoporphyrin in a KB cell line.

OBJECTIVE: The objective of this study is to investigate the effect of intracellular photosensitizer distribution on tumor cell death after photodynamic therapy (PDT). BACKGROUND DATA: The photosensitizer accumulates in tumor tissue during PDT, and generates intracellular reactive oxygen species (ROS), resulting in tumor cell death. MATERIALS AND METHODS: This study was carried out to elucidate the effects of PDT in a KB oral cancer cell line using hematoporphyrin with irradiation at 635 nm and 5 mW/cm(2). After irradiation, the MTT reduction method, agarose gel electrophoresis, flow cytometry, and Diff-Quick staining were performed. The intracellular ROS level was measured by DCF-DA. Intracellular hematoporphyrin was monitored with a confocal microscope, and Western blot and caspase activity assays were performed. RESULTS: In our study, cell survival was reduced by about 50% after 3 h of hematoporphyrin incubation time. In DNA fragmentation, flow cytometry, and Diff-Quick assay, necrosis was identified within 12 h and apoptosis soon thereafter. Confocal microscopy revealed that hematoporphyrin was localized in the cell membrane, cytoplasm, and nucleus as time passed. The quantities of intracellular ROS correlated with the time of hematoporphyrin accumulation. Additionally, Western blot analysis of Bcl-2/Bax, the release of cytochrome C, and activity of caspase-3 and caspase-9 showed that apoptosis followed the mitochondria-dependent pathway. CONCLUSION: PDT with hematoporphyrin in the KB cell line showed morphological changes of cell necrosis and apoptosis, which were associated with the time of distribution and localization of hematoporphyrin. Also, the apoptosis evoked followed the mitochondria-dependent pathway.

Potential ability of hematoporphyrin to enhance an optical coherence tomographic image of gastric cancer in vivo in mice.

An ideal diagnostic system for the tumor tissues should be able to detect and define the location of tumor tissues and the early development of malignant diseases. There is great need for enhancement of imaging ability to tumor tissues. Optical coherence tomography (OCT) is used in detection and location of varied tumor tissues. In order to improve the sensitivity and specificity of an OCT image, hematoporphyrin as a new type of contrast agent was used in this study. The orthotopic graft model of gastric cancer in nude mice was used. The image formations of the tumor tissues without and with injection of hematoporphyrin in vivo were obtained by an OCT system at a 1,310 nm central wavelength. The experimental results showed that the tumor tissues accumulated with hematoporphyrin have an ability of light absorption which results in the increase of signal attenuation in the gastric cancer tissues, and that the boundary between the tumor tissues and surrounding normal tissues was perfectly defined owing to the accumulation of hematoporphyrin. From the experimental results, it is found that hematoporphyrin, a photosensitizing agent, could be used as a contrast agent for OCT imaging of tumor tissues, which offer an effective OCT image method for clinical detection and localization of tumor tissues in vivo.

Development and validation of a sensitive quantification method for hematoporphyrin monomethyl ether in plasma using high-performance liquid chromatography with fluorescence detection.

A rapid, sensitive, precise and specific method for determination of hematoporphyrin monomethyl ether (HMME), a novel photodynamic therapy (PDT) drug, was developed and validated using high-performance liquid chromatography (HPLC) with fluorescence detection. HMME was isolated from the plasma by a single-step liquid-liquid extraction with ethyl acetate. The analyte and internal standard fluorescein were baseline separated on a Diamonsil C(18) analytical column (4.6 x 150 mm, 5 microm) and analyzed using a fluorescence detector with the excitation and emission wavelengths set at 395 and 613 nm, respectively. The method was linear in the concentration range 0.025-5 microg/mL with a lower limit of quantitation (LLOQ) of 10 ng/mL. The inter- and intra-day accuracies and precisions were all within 10% and the mean recoveries of HMME and fluorescein were 95 +/- 3.7 and 90 +/- 2.3%, respectively. The analyte was stable during all sample storage, preparation and analysis periods. This method was successfully applied to a pharmacokinetic study after a single-dose intravenous administration of HMME (5 mg/kg) to beagle dogs. This method was reproducible and sensitive enough for the pharmacokinetic study of HMME. Based on the results of the pharmacokinetic study, we suggest that a rather long light-avoiding time is essential for patients under HMME therapy.

Photodynamic therapy of brain tumours: evaluation of porphyrin uptake versus clinical outcome.

The objective of this study was to investigate whether the level of the photosensitizer haematoporphyrin derivative (HpD) uptake measured in tissue samples taken from brain tumour patients was associated with survival post-treatment with photodynamic therapy (PDT). The mean HpD uptake in tumour tissue was significantly higher in glioblastoma multiforme than anaplastic astrocytoma. Recurrent tumours had a higher mean uptake compared to primary tumours, which was evident in all grades of tumour. Among patients with GBM, there was a significant association between greater HpD uptake and survival (HR = 0.26 [0.12, 0.59], p = 0.001). There was also some evidence of a weak association between greater HpD uptake and survival among patients with AA, although the result was inconclusive (HR = 0.73 [0.32, 1.71], p = 0.472).