The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Alfred Fahr - One of the best experts on this subject based on the ideXlab platform.
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transfer of a lipophilic drug Temoporfin between small unilamellar liposomes and human plasma proteins influence of membrane composition on vesicle integrity and release characteristics
Journal of Liposome Research, 2013Co-Authors: Christiane Decker, Frank Steiniger, Alfred FahrAbstract:AbstractThe introduction of PEG lipid conjugates into lipid bilayers leads to long circulating liposomes with improved pharmacokinetics and pharmacodynamics characteristics. The concentration range of PEG-lipids is limited by their micelle forming properties. We investigated two phosphatidyl oligoglycerols as potential alternatives to PEG-lipid conjugates and compared their micelle forming properties after incorporation of increasing amounts of oligoglycerols into gel-phase liposomes via cryo-transmission electron microscopy. The incorporation of highly hydrophobic drugs into liposomes makes water soluble formulations possible and improves the therapeutic properties of the drug. We incorporated the hydrophobic photosensitizer Temoporfin into liposomes varying in membrane fluidity and nature of surface modifying agents. The main purpose of this study was the investigation of liposome integrity and Temoporfin incorporation stability in the presence of plasma. After incubation of Temoporfin-loaded liposomes ...
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pharmacokinetics of Temoporfin loaded liposome formulations correlation of liposome and Temoporfin blood concentration
Journal of Controlled Release, 2013Co-Authors: Christiane Decker, Harald Schubert, Sylvio May, Alfred FahrAbstract: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.
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wheat germ agglutinin modified liposomes for the photodynamic inactivation of bacteria
Photochemistry and Photobiology, 2012Co-Authors: Kewei Yang, Burkhard Gitter, Ronny Ruger, Volker Albrecht, Gerhard D Wieland, Alfred FahrAbstract:Photodynamic inactivation (PDI) of bacteria is a promising approach for combating the increasing emergence of antibiotic resistance in pathogenic bacteria. To further improve the PDI efficiency on bacteria, a bacteria-targeting liposomal formulation was investigated. A generation II photosensitizer (Temoporfin) was incorporated into liposomes, followed by conjugation with a specific lectin (wheat germ agglutinin, WGA) on the liposomal surface. WGA was successfully coupled to Temoporfin-loaded liposomes using an activated phospholipid containing N-hydroxylsuccinimide residue. Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa were selected to evaluate the WGA modified liposomes in terms of bacteria targeted delivery and in vitro PDI test. Fluorescence microscopy revealed that Temoporfin was delivered to both kinds of bacteria, while flow cytometry demonstrated that WGA- modified liposomes delivered more Temoporfin to bacteria compared to nonmodified liposomes. Consequently, the WGA- modified liposomes eradicated all MRSA and significantly enhanced the PDI of P. aeruginosa. In conclusion, the WGA- modified liposomes are a promising formulation for bacteria targeted delivery of Temoporfin and for improving the PDI efficiency of Temoporfin on both Gram-positive and Gram-negative bacterial cells.
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fast high throughput screening of Temoporfin loaded liposomal formulations prepared by ethanol injection method
Journal of Liposome Research, 2012Co-Authors: Kewei Yang, Joseph T Delaney, Ulrich S Schubert, Alfred FahrAbstract:A new strategy for fast, convenient high-throughput screening of liposomal formulations was developed, utilizing the automation of the so-called ethanol-injection method. This strategy was illustrated by the preparation and screening of the liposomal formulation library of a potent second-generation photosensitizer, Temoporfin. Numerous liposomal formulations were efficiently prepared using a pipetting robot, followed by automated size characterization, using a dynamic light scattering plate reader. Incorporation efficiency of Temoporfin and zeta potential were also detected in selected cases. To optimize the formulation, different parameters were investigated, including lipid types, lipid concentration in injected ethanol, ratio of ethanol to aqueous solution, ratio of drug to lipid, and the addition of functional phospholipid. Step-by-step small liposomes were prepared with high incorporation efficiency. At last, an optimized formulation was obtained for each lipid in the following condition: 36.4 mg·mL...
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antimicrobial peptide modified liposomes for bacteria targeted delivery of Temoporfin in photodynamic antimicrobial chemotherapy
Photochemical and Photobiological Sciences, 2011Co-Authors: Kewei Yang, Burkhard Gitter, Ronny Ruger, Volker Albrecht, Gerhard D Wieland, Ming Chen, Xiangli Liu, Alfred FahrAbstract:Photodynamic antimicrobial chemotherapy (PACT) and antimicrobial peptides (AMPs) are two promising strategies to combat the increasing prevalence of antibiotic-resistant bacteria. To take advantage of these two strategies, we integrated a novel antimicrobial peptide (WLBU2) and a potent generation II photosensitizer (Temoporfin) into liposomes by preparing WLBU2-modified liposomes, aiming at bacteria targeted delivery of Temoporfin for PACT. WLBU2 was successfully coupled to Temoporfin-loaded liposomes using a functional phospholipid. The delivery of Temoporfin to bacteria was confirmed by fluorescence microscopy and flow cytometry, thus demonstrating that more Temoporfin was delivered to bacteria by WLBU2-modified liposomes than by unmodified liposomes. Consequently, the WLBU2-modified liposomes eradicated all methicillin-resistant Staphylococcus aureus (MRSA) and induced a 3.3 log10 reduction of Pseudomonas aeruginosa in the in vitro photodynamic inactivation test. These findings demonstrate that the use of AMP-modified liposomes is promising for bacteria-targeted delivery of photosensitizers and for improving the PACT efficiency against both gram-positive and gram-negative bacteria in the local infections.
Nina Dragiceviccuric - One of the best experts on this subject based on the ideXlab platform.
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efficacy of Temoporfin loaded invasomes in the photodynamic therapy in human epidermoid and colorectal tumour cell lines
Journal of Photochemistry and Photobiology B-biology, 2010Co-Authors: Nina Dragiceviccuric, Susanna Grafe, Burkhard Gitter, Alfred FahrAbstract:Abstract In the case of cutaneous malignant or non-malignant diseases, topical photodynamic therapy (PDT) with a Temoporfin (mTHPC)-containing formulation would be advantageous. Unfortunately, mTHPC is a highly hydrophobic drug with low percutaneous absorption and novel mTHPC-loaded invasomes for enhanced skin delivery were developed. The purpose of this study was to investigate photodynamic efficacy of mTHPC-loaded invasomes in vitro in two cell lines, i.e. the human colorectal tumour cell line HT29 and the epidermoid tumour cell line A431. Invasomes are vesicles containing besides phospholipids a mixture of terpenes or only one terpene and ethanol. Dark toxicity, phototoxicity and intracellular localization of mTHPC were studied. Laser scanning microscopy indicated perinuclear localization of mTHPC. Results revealed that mTHPC-invasomes and mTHPC-ethanolic solution used at a 2 μM mTHPC-concentration and photoirradiation at 20 J/cm 2 were able to reduce survival of HT29 cells and especially of A431 cells, being more sensitive to PDT. In contrast to HT29 cells, where there was not a significant difference between cytotoxicity of mTHPC-ethanolic solution and mTHPC-invasomes, in A431 cells mTHPC-invasomes were more cytotoxic. Survival of about 16% of A431 cells treated with mTHPC-invasomes is very promising, since it demonstrates invasomes’ potential to be used in topical PDT of cutaneous malignant diseases.
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surface charged Temoporfin loaded flexible vesicles in vitro skin penetration studies and stability
International Journal of Pharmaceutics, 2010Co-Authors: Nina Dragiceviccuric, Susanna Grafe, Burkhard Gitter, Sven Winter, Alfred FahrAbstract:In order to increase topical delivery of Temoporfin (mTHPC), a highly hydrophobic photosensitizer with low percutaneous penetration, neutral, anionic and cationic flexible liposomes (i.e. flexosomes) were prepared and investigated for their penetration enhancing ability. The in vitro skin penetration study was performed using human abdominal skin mounted in Franz diffusion cells. Besides the effect of surface charge of flexosomes on skin penetration of mTHPC, also its effect on physical properties (particle size, polydispersity index, lamellarity) and physicochemical stability of vesicles was investigated. Photon-correlation spectroscopy revealed that vesicles had after preparation a small particle size and low polydispersity index, while cryo-electron microscopy confirmed that these vesicles were mostly unilamellar and of a spherical shape. Regarding stability, contrasting to anionic flexosomes showing lack of long-term stability, neutral and cationic flexosomes were stable during 9 months storage at 4 degrees C. As to the penetration enhancing ability, cationic flexosomes possessed the highest, i.e. they delivered the highest mTHPC-amount to stratum corneum and deeper skin layers compared to conventional liposomes, neutral and anionic flexosomes. In conclusion, mTHPC-loaded cationic flexosomes could be a promising tool for delivering mTHPC to the skin, which would be beneficial for the photodynamic therapy of cutaneous malignant or non-malignant diseases.
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surface charged Temoporfin loaded flexible vesicles in vitro skin penetration studies and stability
International Journal of Pharmaceutics, 2010Co-Authors: Nina Dragiceviccuric, Susanna Grafe, Burkhard Gitter, Sven Winter, Alfred FahrAbstract:Abstract In order to increase topical delivery of Temoporfin (mTHPC), a highly hydrophobic photosensitizer with low percutaneous penetration, neutral, anionic and cationic flexible liposomes (i.e. flexosomes) were prepared and investigated for their penetration enhancing ability. The in vitro skin penetration study was performed using human abdominal skin mounted in Franz diffusion cells. Besides the effect of surface charge of flexosomes on skin penetration of mTHPC, also its effect on physical properties (particle size, polydispersity index, lamellarity) and physicochemical stability of vesicles was investigated. Photon-correlation spectroscopy revealed that vesicles had after preparation a small particle size and low polydispersity index, while cryo-electron microscopy confirmed that these vesicles were mostly unilamellar and of a spherical shape. Regarding stability, contrasting to anionic flexosomes showing lack of long-term stability, neutral and cationic flexosomes were stable during 9 months storage at 4 °C. As to the penetration enhancing ability, cationic flexosomes possessed the highest, i.e. they delivered the highest mTHPC-amount to stratum corneum and deeper skin layers compared to conventional liposomes, neutral and anionic flexosomes. In conclusion, mTHPC-loaded cationic flexosomes could be a promising tool for delivering mTHPC to the skin, which would be beneficial for the photodynamic therapy of cutaneous malignant or non-malignant diseases.
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development of liposomes containing ethanol for skin delivery of Temoporfin characterization and in vitro penetration studies
Colloids and Surfaces B: Biointerfaces, 2009Co-Authors: Nina Dragiceviccuric, Volker Albrecht, Dietrich Scheglmann, Alfred FahrAbstract:The aim of this study was to develop ethanol-containing (3.3-20%, w/v) liposomes loaded with Temoporfin (mTHPC), which presents a highly hydrophobic photosensitizer with low percutaneous penetration, and to investigate their skin penetration enhancing effect. Characterization parameters of liposomes were measured by photon correlation spectroscopy, lamellarity was analyzed by cryo-electron microscopy and mTHPC-content in formulations was determined spectrofotometrically. In order to assess the stability of mTHPC-liposomes at 4 and 23 degrees C, at predetermined time intervals characterization parameters and mTHPC-content were measured. The in vitro skin penetration of mTHPC was investigated using human abdominal skin mounted in Franz cells. The results indicated that mTHPC-liposomes were of a small particle size, small polydispersity index, negative surface charge, unilamellar or oligolamellar, and of a spherical or oval shape. All liposomes were stable during 12 months' storage at 4 degrees C. Increasing the amount of ethanol in mTHPC-liposomes the skin deposition of mTHPC increased also. Liposomes without ethanol delivered the lowest amount of mTHPC into the skin, while liposomes containing 20% ethanol showed the highest penetration enhancement. In conclusion, mTHPC-liposomes containing 20% ethanol could be a promising tool for delivering Temoporfin to the skin, which would be beneficial for the photodynamic therapy of cutaneous malignant or non-malignant diseases.
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stability evaluation of Temoporfin loaded liposomal gels for topical application
Journal of Liposome Research, 2009Co-Authors: Nina Dragiceviccuric, Sven Winter, Danina Krajisnik, Mirjana Stupar, Jela Milic, Susanna Graefe, Alfred FahrAbstract:Temoporfin (mTHPC) is a potent second-generation synthetic photosensitizer. Topical delivery of mTHPC is of great interest for the photodynamic therapy of psoriasis and superficial skin cancer lesions. The aim of this study was to evaluate the stability of hydrophilic gels containing mTHPC-loaded liposomes. Two different mTHPC-loaded liposome dispersions, composed of 15 % (w/w) nonhydrogenated soybean lecithin of different phosphatidylcholine content, were prepared and incorporated (2:1 w/w) into hydrogels of different carbomer concentrations (1.5, 2.25, and 3%; w/w). Obtained liposomal hydrogels, containing 0.15% (w/w) mTHPC, 10% (w/w) phospholipids, and 0, 0.5, or 1% (w/w) carbomer, were analyzed for flow properties, liposome particle size, and polydispersity index (PDI), pH value, and mTHPC content after their preparation and at predetermined time intervals during 6 months of storage at 4 and 23 degrees C. All hydrogels showed, during the whole period of investigation, adequate characteristics for topical application (i.e., they revealed shear-thinning plastic flow behavior). Rheological parameters, particle size, and PDI of liposomes in hydrogels, mTHPC content, and pH value did not show remarkable changes during the storage of gels, which could make them unacceptable for topical use. The obtained results indicated physical and chemical stability of liposomal gels containing mTHPC during 6 months of storage at both temperatures.
Dietrich Scheglmann - One of the best experts on this subject based on the ideXlab platform.
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predicting human pharmacokinetics of liposomal Temoporfin using a hybrid in silico model
European Journal of Pharmaceutics and Biopharmaceutics, 2020Co-Authors: Laura Jablonka, Volker Albrecht, Dietrich Scheglmann, Mukul Ashtikar, Ge Fiona Gao, Manuela Thurn, Harshvardhan Modh, Jiongwei Wang, Annegret Preus, Beate RoderAbstract:Abstract Over the years, the performance of the liposomal formulations of Temoporfin, Foslip® and Fospeg®, was investigated in a broad array of cell-based assays and preclinical animal models. So far, little attention has been paid to the influence of drug release and liposomal stability on the plasma concentration–time profile. The drug release is a key attribute which impacts product quality and the in vivo efficacy of nanocarrier formulations. In the present approach, the in vitro drug release and the drug-protein transfer of Foslip® and Fospeg® was determined using the dispersion releaser technology. To analyze the stability of both formulations in physiological fluids, nanoparticle tracking analysis was applied. A comparable drug release behavior and a high physical stability with a vesicle size of approximately 92 ± 2 nm for Foslip® and at 111 ± 5 nm for Fospeg® were measured. The development of a novel hybrid in silico model resulted in an optimal representation of the in vivo data. Based on the information available for previous formulations, the model enabled a prediction of the performance of Foslip® in humans. To verify the simulations, plasma concentration–time profiles of a phase I clinical trial were used. An absolute average fold error of 1.4 was achieved. Moreover, a deconvolution of the pharmacokinetic profile into different fractions relevant for the in vivo efficacy and safety was achieved. While the total plasma concentration reached a cmax of 2298 ng/mL after 0.72 h, the monomolecular drug accounted for a small fraction of the photosensitizer with a cmax of 321 ng/mL only.
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matryoshka type liposomes offer the improved delivery of Temoporfin to tumor spheroids
Cancers, 2019Co-Authors: Ilya Yakavets, Vladimir Zorin, Henri-pierre Lassalle, Dietrich Scheglmann, Marie Millard, Arno Wiehe, Laureline Lamy, Aurelie FrancoisAbstract:The balance between the amount of drug delivered to tumor tissue and the homogeneity of its distribution is a challenge in the efficient delivery of photosensitizers (PSs) in photodynamic therapy (PDT) of cancer. To date, many efforts have been made using various nanomaterials to efficiently deliver Temoporfin (mTHPC), one of the most potent photosensitizers. The present study aimed to develop double-loaded matryoshka-type hybrid nanoparticles encapsulating mTHPC/cyclodextrin inclusion complexes in mTHPC-loaded liposomes. This system was expected to improve the transport of mTHPC to target tissues and to strengthen its accumulation in the tumor tissue. Double-loaded hybrid nanoparticles (DL-DCL) were prepared, characterized, and tested in 2D and 3D in vitro models and in xenografted mice in vivo. Our studies indicated that DL-DCL provided deep penetration of mTHPC into the multicellular tumor spheroids via cyclodextrin nanoshuttles once the liposomes had been destabilized by serum proteins. Unexpectedly, we observed similar PDT efficiency in xenografted HT29 tumors for liposomal mTHPC formulation (Foslip®) and DL-DCL.
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advanced in silico modeling explains pharmacokinetics and biodistribution of Temoporfin nanocrystals in humans
Journal of Controlled Release, 2019Co-Authors: Laura Jablonka, Volker Albrecht, Dietrich Scheglmann, Mukul Ashtikar, Manuela Thurn, Annegret Preus, Beate Roder, Ge Gao, Fabian Jung, Matthias G WackerAbstract:Foscan®, a formulation comprising Temoporfin dissolved in a mixture of ethanol and propylene glycol, has been approved in Europe for palliative photodynamic therapy of squamous cell carcinoma of the head and neck. During clinical and preclinical studies it was observed that considering the administration route, the drug presents a rather atypical plasma profile as plasma concentration peaks delayed. Possible explanations, as for example the formation of a drug depot or aggregation after intravenous administration, are discussed in current literature. In the present study an advanced in silico model was developed and evaluated for the detailed description of Foscan® pharmacokinetics. Therefore, in vitro release data obtained from experiments with the dispersion releaser technology investigating dissolution pressures of various release media on the drug as well as in vivo data obtained from a clinical study were included into the in silico models. Furthermore, precipitation experiments were performed in presence of biorelevant media and precipitates were analyzed by nanoparticle tracking analysis. Size analysis and particle fraction were also incorporated in this model and a sensitivity analysis was performed. An optimal description of the in vivo situation based on in vitro release and particle characterization data was achieved, as demonstrated by an absolute average fold error of 1.21. This in vitro-in vivo correlation provides an explanation for the pharmacokinetics of Foscan® in humans.
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Temoporfin-in-cyclodextrin-in-lposome - A new approach for anticancer drug delivery: The optimization of composition
Nanomaterials, 2018Co-Authors: Ilya Yakavets, Vladimir Zorin, Henri-pierre Lassalle, Dietrich Scheglmann, Arno Wiehe, Lina BezdetnayaAbstract:The main goal of this study was to use hybrid delivery system for effective transportation of Temoporfin (meta-tetrakis(3-hydroxyphenyl)chlorin, mTHPC) to target tissue. We suggested to couple two independent delivery systems (liposomes and inclusion complexes) to achieve drug-in-cyclodextrin-in-liposome (DCL) nanoconstructs. We further optimized the composition of DCLs, aiming to alter in a more favorable way a distribution of Temoporfin in tumor tissue. We have prepared DCLs with different compositions varying the concentration of mTHPC and the type of β-cyclodextrin (β-CD) derivatives (Hydroxypropyl-, Methyl- and Trimethyl-β-CD). DCLs were prepared by thin-hydration technique and mTHPC/β-CD complexes were added at hydration step. The size was about 135 nm with the surface charge of (−38 mV). We have demonstrated that DCLs are stable and almost all mTHPC is bound to β-CDs in the inner aqueous liposome core. Among all tested DCLs, trimethyl-β-CD-based DCL demonstrated a homogenous accumulation of mTHPC across tumor spheroid volume, thus supposing optimal mTHPC distribution.
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Temoporfin-in-Cyclodextrin-in-Liposome—A New Approach for Anticancer Drug Delivery: The Optimization of Composition
'MDPI AG', 2018Co-Authors: Ilya Yakavets, Vladimir Zorin, Henri-pierre Lassalle, Dietrich Scheglmann, Arno Wiehe, Lina BezdetnayaAbstract:The main goal of this study was to use hybrid delivery system for effective transportation of Temoporfin (meta-tetrakis(3-hydroxyphenyl)chlorin, mTHPC) to target tissue. We suggested to couple two independent delivery systems (liposomes and inclusion complexes) to achieve drug-in-cyclodextrin-in-liposome (DCL) nanoconstructs. We further optimized the composition of DCLs, aiming to alter in a more favorable way a distribution of Temoporfin in tumor tissue. We have prepared DCLs with different compositions varying the concentration of mTHPC and the type of β-cyclodextrin (β-CD) derivatives (Hydroxypropyl-, Methyl- and Trimethyl-β-CD). DCLs were prepared by thin-hydration technique and mTHPC/β-CD complexes were added at hydration step. The size was about 135 nm with the surface charge of (−38 mV). We have demonstrated that DCLs are stable and almost all mTHPC is bound to β-CDs in the inner aqueous liposome core. Among all tested DCLs, trimethyl-β-CD-based DCL demonstrated a homogenous accumulation of mTHPC across tumor spheroid volume, thus supposing optimal mTHPC distribution
Burkhard Gitter - One of the best experts on this subject based on the ideXlab platform.
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wheat germ agglutinin modified liposomes for the photodynamic inactivation of bacteria
Photochemistry and Photobiology, 2012Co-Authors: Kewei Yang, Burkhard Gitter, Ronny Ruger, Volker Albrecht, Gerhard D Wieland, Alfred FahrAbstract:Photodynamic inactivation (PDI) of bacteria is a promising approach for combating the increasing emergence of antibiotic resistance in pathogenic bacteria. To further improve the PDI efficiency on bacteria, a bacteria-targeting liposomal formulation was investigated. A generation II photosensitizer (Temoporfin) was incorporated into liposomes, followed by conjugation with a specific lectin (wheat germ agglutinin, WGA) on the liposomal surface. WGA was successfully coupled to Temoporfin-loaded liposomes using an activated phospholipid containing N-hydroxylsuccinimide residue. Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa were selected to evaluate the WGA modified liposomes in terms of bacteria targeted delivery and in vitro PDI test. Fluorescence microscopy revealed that Temoporfin was delivered to both kinds of bacteria, while flow cytometry demonstrated that WGA- modified liposomes delivered more Temoporfin to bacteria compared to nonmodified liposomes. Consequently, the WGA- modified liposomes eradicated all MRSA and significantly enhanced the PDI of P. aeruginosa. In conclusion, the WGA- modified liposomes are a promising formulation for bacteria targeted delivery of Temoporfin and for improving the PDI efficiency of Temoporfin on both Gram-positive and Gram-negative bacterial cells.
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antimicrobial peptide modified liposomes for bacteria targeted delivery of Temoporfin in photodynamic antimicrobial chemotherapy
Photochemical and Photobiological Sciences, 2011Co-Authors: Kewei Yang, Burkhard Gitter, Ronny Ruger, Volker Albrecht, Gerhard D Wieland, Ming Chen, Xiangli Liu, Alfred FahrAbstract:Photodynamic antimicrobial chemotherapy (PACT) and antimicrobial peptides (AMPs) are two promising strategies to combat the increasing prevalence of antibiotic-resistant bacteria. To take advantage of these two strategies, we integrated a novel antimicrobial peptide (WLBU2) and a potent generation II photosensitizer (Temoporfin) into liposomes by preparing WLBU2-modified liposomes, aiming at bacteria targeted delivery of Temoporfin for PACT. WLBU2 was successfully coupled to Temoporfin-loaded liposomes using a functional phospholipid. The delivery of Temoporfin to bacteria was confirmed by fluorescence microscopy and flow cytometry, thus demonstrating that more Temoporfin was delivered to bacteria by WLBU2-modified liposomes than by unmodified liposomes. Consequently, the WLBU2-modified liposomes eradicated all methicillin-resistant Staphylococcus aureus (MRSA) and induced a 3.3 log10 reduction of Pseudomonas aeruginosa in the in vitro photodynamic inactivation test. These findings demonstrate that the use of AMP-modified liposomes is promising for bacteria-targeted delivery of photosensitizers and for improving the PACT efficiency against both gram-positive and gram-negative bacteria in the local infections.
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efficacy of Temoporfin loaded invasomes in the photodynamic therapy in human epidermoid and colorectal tumour cell lines
Journal of Photochemistry and Photobiology B-biology, 2010Co-Authors: Nina Dragiceviccuric, Susanna Grafe, Burkhard Gitter, Alfred FahrAbstract:Abstract In the case of cutaneous malignant or non-malignant diseases, topical photodynamic therapy (PDT) with a Temoporfin (mTHPC)-containing formulation would be advantageous. Unfortunately, mTHPC is a highly hydrophobic drug with low percutaneous absorption and novel mTHPC-loaded invasomes for enhanced skin delivery were developed. The purpose of this study was to investigate photodynamic efficacy of mTHPC-loaded invasomes in vitro in two cell lines, i.e. the human colorectal tumour cell line HT29 and the epidermoid tumour cell line A431. Invasomes are vesicles containing besides phospholipids a mixture of terpenes or only one terpene and ethanol. Dark toxicity, phototoxicity and intracellular localization of mTHPC were studied. Laser scanning microscopy indicated perinuclear localization of mTHPC. Results revealed that mTHPC-invasomes and mTHPC-ethanolic solution used at a 2 μM mTHPC-concentration and photoirradiation at 20 J/cm 2 were able to reduce survival of HT29 cells and especially of A431 cells, being more sensitive to PDT. In contrast to HT29 cells, where there was not a significant difference between cytotoxicity of mTHPC-ethanolic solution and mTHPC-invasomes, in A431 cells mTHPC-invasomes were more cytotoxic. Survival of about 16% of A431 cells treated with mTHPC-invasomes is very promising, since it demonstrates invasomes’ potential to be used in topical PDT of cutaneous malignant diseases.
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surface charged Temoporfin loaded flexible vesicles in vitro skin penetration studies and stability
International Journal of Pharmaceutics, 2010Co-Authors: Nina Dragiceviccuric, Susanna Grafe, Burkhard Gitter, Sven Winter, Alfred FahrAbstract:Abstract In order to increase topical delivery of Temoporfin (mTHPC), a highly hydrophobic photosensitizer with low percutaneous penetration, neutral, anionic and cationic flexible liposomes (i.e. flexosomes) were prepared and investigated for their penetration enhancing ability. The in vitro skin penetration study was performed using human abdominal skin mounted in Franz diffusion cells. Besides the effect of surface charge of flexosomes on skin penetration of mTHPC, also its effect on physical properties (particle size, polydispersity index, lamellarity) and physicochemical stability of vesicles was investigated. Photon-correlation spectroscopy revealed that vesicles had after preparation a small particle size and low polydispersity index, while cryo-electron microscopy confirmed that these vesicles were mostly unilamellar and of a spherical shape. Regarding stability, contrasting to anionic flexosomes showing lack of long-term stability, neutral and cationic flexosomes were stable during 9 months storage at 4 °C. As to the penetration enhancing ability, cationic flexosomes possessed the highest, i.e. they delivered the highest mTHPC-amount to stratum corneum and deeper skin layers compared to conventional liposomes, neutral and anionic flexosomes. In conclusion, mTHPC-loaded cationic flexosomes could be a promising tool for delivering mTHPC to the skin, which would be beneficial for the photodynamic therapy of cutaneous malignant or non-malignant diseases.
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surface charged Temoporfin loaded flexible vesicles in vitro skin penetration studies and stability
International Journal of Pharmaceutics, 2010Co-Authors: Nina Dragiceviccuric, Susanna Grafe, Burkhard Gitter, Sven Winter, Alfred FahrAbstract:In order to increase topical delivery of Temoporfin (mTHPC), a highly hydrophobic photosensitizer with low percutaneous penetration, neutral, anionic and cationic flexible liposomes (i.e. flexosomes) were prepared and investigated for their penetration enhancing ability. The in vitro skin penetration study was performed using human abdominal skin mounted in Franz diffusion cells. Besides the effect of surface charge of flexosomes on skin penetration of mTHPC, also its effect on physical properties (particle size, polydispersity index, lamellarity) and physicochemical stability of vesicles was investigated. Photon-correlation spectroscopy revealed that vesicles had after preparation a small particle size and low polydispersity index, while cryo-electron microscopy confirmed that these vesicles were mostly unilamellar and of a spherical shape. Regarding stability, contrasting to anionic flexosomes showing lack of long-term stability, neutral and cationic flexosomes were stable during 9 months storage at 4 degrees C. As to the penetration enhancing ability, cationic flexosomes possessed the highest, i.e. they delivered the highest mTHPC-amount to stratum corneum and deeper skin layers compared to conventional liposomes, neutral and anionic flexosomes. In conclusion, mTHPC-loaded cationic flexosomes could be a promising tool for delivering mTHPC to the skin, which would be beneficial for the photodynamic therapy of cutaneous malignant or non-malignant diseases.
Susanna Grafe - One of the best experts on this subject based on the ideXlab platform.
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photodynamic activity of Temoporfin nanoparticles induces a shift to the m1 like phenotype in m2 polarized macrophages
Journal of Photochemistry and Photobiology B-biology, 2018Co-Authors: Zhenxin Zhu, Susanna Grafe, Claudia Scalfihapp, Anastasia V Ryabova, Arno Wiehe, Ralfuwe Peter, Victor B Loschenov, Rudolf Steiner, Rainer WittigAbstract:Abstract The monocyte/macrophage cell lineage reveals an enormous plasticity, which is required for tissue homeostasis, but is also undermined in various disease states, leading to a functional involvement of macrophages in major human diseases such as atherosclerosis and cancer. We recently generated in vivo evidence that crystalline, nonfluorescent nanoparticles of the hydrophobic porphyrin-related photosensitizer Aluminum phthalocyanine are selectively dissolved and thus may be used for specific fluorescent labelling of rejected, but not of accepted xenotransplants. This led us to hypothesize that nanoparticles made of planar photosensitizers such as porphyrins and chlorins were preferentially taken up and dissolved by macrophages, which was verified by in vitro studies. Here, using an in vitro system for macrophage differentiation/polarization of the human monocyte THP-1 cell line, we demonstrate differential uptake/dissolution of Temoporfin-derived nanoparticles in polarized macrophages, which resulted in differential photosensitivity. More importantly, low dose photodynamic sensitization using Temoporfin nanoparticles can be used to trigger M1 re-polarization of THP-1 cells previously polarized to the M2 state. Thus, sublethal photodynamic treatment using Temoporfin nanoparticles might be applied to induce a phenotypic shift of tumor-associated macrophages for the correction of an immunosuppressive microenvironment in the treatment of cancer, which may synergize with immune checkpoint inhibition.
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synthesis of β functionalized Temoporfin derivatives for an application in photodynamic therapy
Bioorganic & Medicinal Chemistry Letters, 2011Co-Authors: Daniel Aicher, Susanna Grafe, Christian B W Stark, Arno WieheAbstract:The synthesis of novel β-functionalized derivatives of the clinically used photosensitizer Temoporfin has been achieved by nucleophilic addition reactions to a corresponding diketo chlorin. The β-substituted dihydroxychlorin products exhibit a strong absorption in the red spectral region, a high singlet oxygen quantum yield, and were found to be highly effective in in vitro assays against HT-29 tumor cells.
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efficacy of Temoporfin loaded invasomes in the photodynamic therapy in human epidermoid and colorectal tumour cell lines
Journal of Photochemistry and Photobiology B-biology, 2010Co-Authors: Nina Dragiceviccuric, Susanna Grafe, Burkhard Gitter, Alfred FahrAbstract:Abstract In the case of cutaneous malignant or non-malignant diseases, topical photodynamic therapy (PDT) with a Temoporfin (mTHPC)-containing formulation would be advantageous. Unfortunately, mTHPC is a highly hydrophobic drug with low percutaneous absorption and novel mTHPC-loaded invasomes for enhanced skin delivery were developed. The purpose of this study was to investigate photodynamic efficacy of mTHPC-loaded invasomes in vitro in two cell lines, i.e. the human colorectal tumour cell line HT29 and the epidermoid tumour cell line A431. Invasomes are vesicles containing besides phospholipids a mixture of terpenes or only one terpene and ethanol. Dark toxicity, phototoxicity and intracellular localization of mTHPC were studied. Laser scanning microscopy indicated perinuclear localization of mTHPC. Results revealed that mTHPC-invasomes and mTHPC-ethanolic solution used at a 2 μM mTHPC-concentration and photoirradiation at 20 J/cm 2 were able to reduce survival of HT29 cells and especially of A431 cells, being more sensitive to PDT. In contrast to HT29 cells, where there was not a significant difference between cytotoxicity of mTHPC-ethanolic solution and mTHPC-invasomes, in A431 cells mTHPC-invasomes were more cytotoxic. Survival of about 16% of A431 cells treated with mTHPC-invasomes is very promising, since it demonstrates invasomes’ potential to be used in topical PDT of cutaneous malignant diseases.
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surface charged Temoporfin loaded flexible vesicles in vitro skin penetration studies and stability
International Journal of Pharmaceutics, 2010Co-Authors: Nina Dragiceviccuric, Susanna Grafe, Burkhard Gitter, Sven Winter, Alfred FahrAbstract:Abstract In order to increase topical delivery of Temoporfin (mTHPC), a highly hydrophobic photosensitizer with low percutaneous penetration, neutral, anionic and cationic flexible liposomes (i.e. flexosomes) were prepared and investigated for their penetration enhancing ability. The in vitro skin penetration study was performed using human abdominal skin mounted in Franz diffusion cells. Besides the effect of surface charge of flexosomes on skin penetration of mTHPC, also its effect on physical properties (particle size, polydispersity index, lamellarity) and physicochemical stability of vesicles was investigated. Photon-correlation spectroscopy revealed that vesicles had after preparation a small particle size and low polydispersity index, while cryo-electron microscopy confirmed that these vesicles were mostly unilamellar and of a spherical shape. Regarding stability, contrasting to anionic flexosomes showing lack of long-term stability, neutral and cationic flexosomes were stable during 9 months storage at 4 °C. As to the penetration enhancing ability, cationic flexosomes possessed the highest, i.e. they delivered the highest mTHPC-amount to stratum corneum and deeper skin layers compared to conventional liposomes, neutral and anionic flexosomes. In conclusion, mTHPC-loaded cationic flexosomes could be a promising tool for delivering mTHPC to the skin, which would be beneficial for the photodynamic therapy of cutaneous malignant or non-malignant diseases.
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surface charged Temoporfin loaded flexible vesicles in vitro skin penetration studies and stability
International Journal of Pharmaceutics, 2010Co-Authors: Nina Dragiceviccuric, Susanna Grafe, Burkhard Gitter, Sven Winter, Alfred FahrAbstract:In order to increase topical delivery of Temoporfin (mTHPC), a highly hydrophobic photosensitizer with low percutaneous penetration, neutral, anionic and cationic flexible liposomes (i.e. flexosomes) were prepared and investigated for their penetration enhancing ability. The in vitro skin penetration study was performed using human abdominal skin mounted in Franz diffusion cells. Besides the effect of surface charge of flexosomes on skin penetration of mTHPC, also its effect on physical properties (particle size, polydispersity index, lamellarity) and physicochemical stability of vesicles was investigated. Photon-correlation spectroscopy revealed that vesicles had after preparation a small particle size and low polydispersity index, while cryo-electron microscopy confirmed that these vesicles were mostly unilamellar and of a spherical shape. Regarding stability, contrasting to anionic flexosomes showing lack of long-term stability, neutral and cationic flexosomes were stable during 9 months storage at 4 degrees C. As to the penetration enhancing ability, cationic flexosomes possessed the highest, i.e. they delivered the highest mTHPC-amount to stratum corneum and deeper skin layers compared to conventional liposomes, neutral and anionic flexosomes. In conclusion, mTHPC-loaded cationic flexosomes could be a promising tool for delivering mTHPC to the skin, which would be beneficial for the photodynamic therapy of cutaneous malignant or non-malignant diseases.
