head of the department: Prof. Lehr

Recent Submissions

  • Extracellular vesicles as antigen carriers for novel vaccination avenues.

    Mehanny, Mina; Lehr, Claus-Michael; Fuhrmann, Gregor; HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (Elsevier, 2021-03-26)
    Antigen delivery has always been a challenge in scientific practice of vaccine formulation. Yet, mammalian extracellular vesicles (EVs) or bacterial membrane vesicles (MVs) provide an innovative avenue for safe and effective delivery of antigenic material. They include intrinsically loaded antigens from EV-secreting cells or extrinsically loaded antigens onto pre-formed vesicles. Interestingly, many studies shed light on potential novel anti-cancer vaccination immunotherapy for therapeutic applications from mammalian cell host-derived EVs, as well as conventional vaccination for prophylactic applications using bacterial cell-derived MVs against infectious diseases. Here, we discuss the rationale, status quo and potential for both vaccine applications using EVs.
  • A New PqsR Inverse Agonist Potentiates Tobramycin Efficacy to Eradicate Pseudomonas aeruginosa Biofilms

    Schütz, Christian; Ho, Duy‐Khiet; Hamed, Mostafa Mohamed; Abdelsamie, Ahmed Saad; Röhrig, Teresa; Herr, Christian; Kany, Andreas Martin; Rox, Katharina; Schmelz, Stefan; Siebenbürger, Lorenz; et al. (Wiley and Sons Inc., 2021-03-18)
    Pseudomonas aeruginosa (PA) infections can be notoriously difficult to treat and are often accompanied by the development of antimicrobial resistance (AMR). Quorum sensing inhibitors (QSI) acting on PqsR (MvfR) – a crucial transcriptional regulator serving major functions in PA virulence – can enhance antibiotic efficacy and eventually prevent the AMR. An integrated drug discovery campaign including design, medicinal chemistry‐driven hit‐to‐lead optimization and in‐depth biological profiling of a new QSI generation is reported. The QSI possess excellent activity in inhibiting pyocyanin production and PqsR reporter‐gene with IC50 values as low as 200 and 11 × 10−9 m, respectively. Drug metabolism and pharmacokinetics (DMPK) as well as safety pharmacology studies especially highlight the promising translational properties of the lead QSI for pulmonary applications. Moreover, target engagement of the lead QSI is shown in a PA mucoid lung infection mouse model. Beyond that, a significant synergistic effect of a QSI‐tobramycin (Tob) combination against PA biofilms using a tailor‐made squalene‐derived nanoparticle (NP) formulation, which enhance the minimum biofilm eradicating concentration (MBEC) of Tob more than 32‐fold is demonstrated. The novel lead QSI and the accompanying NP formulation highlight the potential of adjunctive pathoblocker‐mediated therapy against PA infections opening up avenues for preclinical development.
  • Local pulmonary drug delivery in the preterm rabbit: feasibility and efficacy of daily intratracheal injections.

    Salaets, Thomas; Gie, André; Jimenez, Julio; Aertgeerts, Margo; Gheysens, Olivier; Vande Velde, Greetje; Koole, Michel; Murgia, Xabi; Casiraghi, Costanza; Ricci, Francesca; et al. (American Physiological Society, 2019-01-24)
    Recent clinical trials in newborns have successfully used surfactant as a drug carrier for an active compound, to minimize systemic exposure. To investigate the translational potential of surfactant-compound mixtures and other local therapeutics, a relevant animal model is required in which intratracheal administration for maximal local deposition is technically possible and well tolerated. Preterm rabbit pups (born at 28 days of gestation) were exposed to either hyperoxia or normoxia and randomized to receive daily intratracheal surfactant, daily intratracheal saline, or no injections for 7 days. At day 7, the overall lung function and morphology were assessed. Efficacy in terms of distribution was assessed by micro-PET-CT on both day 0 and day 7. Lung function as well as parenchymal and vascular structure were altered by hyperoxia, thereby reproducing a phenotype reminiscent of bronchopulmonary dysplasia (BPD). Neither intratracheal surfactant nor saline affected the survival or the hyperoxia-induced BPD phenotype of the pups. Using PET-CT, we demonstrate that 82.5% of the injected radioactive tracer goes and remains in the lungs, with a decrease of only 4% after 150 min. Surfactant and saline can safely and effectively be administered in spontaneously breathing preterm rabbits. The described model and method enable researchers to evaluate intratracheal pharmacological interventions for the treatment of BPD.
  • Tofacitinib Loaded Squalenyl Nanoparticles for Targeted Follicular Delivery in Inflammatory Skin Diseases.

    Christmann, Rebekka; Ho, Duy-Khiet; Wilzopolski, Jenny; Lee, Sangeun; Koch, Marcus; Loretz, Brigitta; Vogt, Thomas; Bäumer, Wolfgang; Schaefer, Ulrich F; Lehr, Claus-Michael; et al. (MDPI, 2020-11-24)
    Tofacitinib (TFB), a Janus kinase inhibitor, has shown excellent success off-label in treating various dermatological diseases, especially alopecia areata (AA). However, TFB's safe and targeted delivery into hair follicles (HFs) is highly desirable due to its systemic adverse effects. Nanoparticles (NPs) can enhance targeted follicular drug delivery and minimize interfollicular permeation and thereby reduce systemic drug exposure. In this study, we report a facile method to assemble the stable and uniform 240 nm TFB loaded squalenyl derivative (SqD) nanoparticles (TFB SqD NPs) in aqueous solution, which allowed an excellent loading capacity (LC) of 20%. The SqD NPs showed an enhanced TFB delivery into HFs compared to the aqueous formulations of plain drug in an ex vivo pig ear model. Furthermore, the therapeutic efficacy of the TFB SqD NPs was studied in a mouse model of allergic dermatitis by ear swelling reduction and compared to TFB dissolved in a non-aqueous mixture of acetone and DMSO (7:1 v/v). Whereas such formulation would not be acceptable for use in the clinic, the TFB SqD NPs dispersed in water illustrated a better reduction in inflammatory effects than plain TFB's aqueous formulation, implying both encouraging good in vivo efficacy and safety. These findings support the potential of TFB SqD NPs for developing a long-term topical therapy of AA.
  • Novel anti-ulcer phytosomal formulation of ethanol extract of pentaclethra macrophylla stem-bark

    Nnamani, Petra O.; Kenechukwu, Franklin C.; Asogwa, Francis O.; Momoh, Mumuni A.; Lehr, Claus Michael; Attama, Anthony A.; HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (, Faculty of Pharmacy, University of Benin, Benin City, Nigeria., 2020-01-01)
    Pentaclethra macrophylla, a medicinal plant widely used for ulcer treatment in Nigeria by herbal practitioners, is limited by poor lipid solubility, resulting in poor absorption and bioavailability. Phytosomes, a novel dosage form that are better absorbed and produce better results than conventional herbal extracts, could be employed to enhance its antiulcer activity. The objective of this study was to formulate Pentaclethra macrophylla stem-bark extract as phytosomes by forming complexes with phospholipid and compare the antiulcer activity with omeprazole, a standard anti-ulcer drug. Phytosomal formulations of ethanol extract of Pentaclethra macrophylla stem-bark and Phospholipon® 90G (P90G) (extract:P90G ratios of 1:1, 1:3, 1:5) were prepared following established method. Their physicochemical properties, in vitro drug release in simulated intestinal fluid (SIF, pH=7.4) and simulated gastric fluid (SGF, pH=1.2) and anti-ulcer properties on aspirin-induced ulcer using Wistar rats were determined and compared with omeprazole. Phytosomes with spherical smooth particles with size range 0.106-0.217 µm and good encapsulation efficiencies (range = 67.61-72.8%) were obtained. Drug release increased with time irrespective of phospholipid concentration or dissolution medium. The extract possessed antiulcer activity (23.33%) which was increased to 33.33, 43.33 and 56.67% by formulating it as phytosomal formulations containing extract:P90G ratios of 1:1, 1:3, 1:5, respectively. However, omeprazole and its formulations gave significantly (p<0.05) greater antiulcer activity when compared with both the ethanol extract and phytosomes. Pentaclethra macrophylla stem-bark possessed antiulcer activity, which was improved via phytosomal formulation. This would serve as potential safer and cheaper alternative therapeutics for ulcer given the side-effects associated with omeprazole.
  • Tobacco Smoke and Inhaled Drugs Alter Expression and Activity of Multidrug Resistance-Associated Protein-1 (MRP1) in Human Distal Lung Epithelial Cells .

    Selo, Mohammed Ali; Delmas, Anne-Sophie; Springer, Lisa; Zoufal, Viktoria; Sake, Johannes A; Clerkin, Caoimhe G; Huwer, Hanno; Schneider-Daum, Nicole; Lehr, Claus-Michael; Nickel, Sabrina; et al. (Frontiers, 2020-09-08)
    Multidrug resistance-associated protein-1 (MRP1/ABCC1) is highly expressed in human lung tissues. Recent studies suggest that it significantly affects the pulmonary disposition of its substrates, both after pulmonary and systemic administration. To better understand the molecular mechanisms involved, we studied the expression, subcellular localization and activity of MRP1 in freshly isolated human alveolar epithelial type 2 (AT2) and type 1-like (AT1-like) cells in primary culture, and in the NCI-H441 cell line. Moreover, the effect of cigarette smoke extract (CSE) and a series of inhaled drugs on MRP1 abundance and activity was investigated in vitro. MRP1 expression levels were measured by q-PCR and immunoblot in AT2 and AT1-like cells from different donors and in several passages of the NCI-H441 cell line. The subcellular localization of the transporter was studied by confocal laser scanning microscopy and cell surface protein biotinylation. MRP1 activity was assessed by bidirectional transport and efflux experiments using the MRP1 substrate, 5(6)-carboxyfluorescein [CF; formed intracellularly from 5(6)-carboxyfluorescein-diacetate (CFDA)] in AT1-like and NCI-H441 cell monolayers. Furthermore, the effect of CSE as well as several bronchodilators and inhaled corticosteroids on MRP1 abundance and CF efflux was investigated. MRP1 protein abundance increased upon differentiation from AT2 to AT1-like phenotype, however, ABCC1 gene levels remained unchanged. MRP1 abundance in NCI-H441 cells were comparable to those found in AT1-like cells. The transporter was detected primarily in basolateral membranes of both cell types which was consistent with net basolateral efflux of CF. Likewise, bidirectional transport studies showed net apical-to-basolateral transport of CF which was sensitive to the MRP1 inhibitor MK-571. Budesonide, beclomethasone dipropionate, salbutamol sulfate, and CSE decreased CF efflux in a concentration-dependent manner. Interestingly, CSE increased MRP1 abundance, whereas budesonide, beclomethasone dipropionate, salbutamol sulfate did not have such effect. CSE and inhaled drugs can reduce MRP1 activity in vitro, which implies the transporter being a potential drug target in the treatment of chronic obstructive pulmonary disease (COPD). Moreover, MRP1 expression level, localization and activity were comparable in human AT1-like and NCI-H441 cells. Therefore, the cell line can be a useful alternative in vitro model to study MRP1 in distal lung epithelium.
  • Pulmonary Surfactant and Drug Delivery: An Interface-Assisted Carrier to Deliver Surfactant Protein SP-D Into the Airways.

    García-Mouton, Cristina; Hidalgo, Alberto; Arroyo, Raquel; Echaide, Mercedes; Cruz, Antonio; Pérez-Gil, Jesús; HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (Frontiers, 2021-01-18)
    This work is focused on the potential use of pulmonary surfactant to deliver full-length recombinant human surfactant protein SP-D (rhSP-D) using the respiratory air-liquid interface as a shuttle. Surfactant protein D (SP-D) is a collectin protein present in the pulmonary surfactant (PS) system, involved in innate immune defense and surfactant homeostasis. It has been recently suggested as a potential therapeutic to alleviate inflammatory responses and lung diseases in preterm infants suffering from respiratory distress syndrome (RDS) or bronchopulmonary dysplasia (BPD). However, none of the current clinical surfactants used for surfactant replacement therapy (SRT) to treat RDS contain SP-D. The interaction of SP-D with surfactant components, the potential of PS as a respiratory drug delivery system and the possibility to produce recombinant versions of human SP-D, brings the possibility of delivering clinical surfactants supplemented with SP-D. Here, we used an in vitro setup that somehow emulates the respiratory air-liquid interface to explore this novel approach. It consists in two different compartments connected with a hydrated paper bridge forming a continuous interface. We firstly analyzed the adsorption and spreading of rhSP-D alone from one compartment to another over the air-liquid interface, observing low interfacial activity. Then, we studied the interfacial spreading of the protein co-administered with PS, both at different time periods or as a mixed formulation, and which oligomeric forms of rhSP-D better traveled associated with PS. The results presented here demonstrated that PS may transport rhSP-D long distances over air-liquid interfaces, either as a mixed formulation or separately in a close window time, opening the doors to empower the current clinical surfactants and SRT.
  • Second-generation lung-on-a-chip with an array of stretchable alveoli made with a biological membrane.

    Zamprogno, Pauline; Wüthrich, Simon; Achenbach, Sven; Thoma, Giuditta; Stucki, Janick D; Hobi, Nina; Schneider-Daum, Nicole; Lehr, Claus-Michael; Huwer, Hanno; Geiser, Thomas; et al. (Nature Pulishing Group, 2021-02-05)
    The air-blood barrier with its complex architecture and dynamic environment is difficult to mimic in vitro. Lung-on-a-chips enable mimicking the breathing movements using a thin, stretchable PDMS membrane. However, they fail to reproduce the characteristic alveoli network as well as the biochemical and physical properties of the alveolar basal membrane. Here, we present a lung-on-a-chip, based on a biological, stretchable and biodegradable membrane made of collagen and elastin, that emulates an array of tiny alveoli with in vivo-like dimensions. This membrane outperforms PDMS in many ways: it does not absorb rhodamine-B, is biodegradable, is created by a simple method, and can easily be tuned to modify its thickness, composition and stiffness. The air-blood barrier is reconstituted using primary lung alveolar epithelial cells from patients and primary lung endothelial cells. Typical alveolar epithelial cell markers are expressed, while the barrier properties are preserved for up to 3 weeks.
  • Modulating the Barrier Function of Human Alveolar Epithelial (hAELVi) Cell Monolayers as a Model of Inflammation.

    Metz, Julia Katharina; Wiegand, Birgit; Schnur, Sabrina; Knoth, Katharina; Schneider-Daum, Nicole; Groß, Henrik; Croston, Glenn; Reinheimer, Torsten Michael; Lehr, Claus-Michael; Hittinger, Marius; et al. (SAGE Publications, 2021-01-29)
    The incidence of inflammatory lung diseases such as acute respiratory distress syndrome (ARDS) remains an important problem, particularly in the present time with the Covid-19 pandemic. However, an adequate in vitro test system to monitor the barrier function of the alveolar epithelium during inflammation and for assessing anti-inflammatory drugs is urgently needed. Therefore, we treated human Alveolar Epithelial Lentivirus-immortalised cells (hAELVi cells) with the pro-inflammatory cytokines TNF-α (25 ng/ml) and IFN-γ (30 ng/ml), in the presence or absence of hydrocortisone (HC). While TNF-α and IFN-γ are known to reduce epithelial barrier properties, HC could be expected to protect the barrier function and result in an anti-inflammatory effect. We investigated the impact of anti-inflammatory/inflammatory treatment on transepithelial electrical resistance (TEER) and the apparent permeability coefficient (P app ) of the low permeability marker sodium fluorescein (NaFlu). After incubating hAELVi cells for 48 hours with a combination of TNF-α and IFN-γ, there was a significant decrease in TEER and a significant increase in the P app . The presence of HC maintained the TEER values and barrier properties, so that no significant P app change was observed. By using hAELVi cells to study anti-inflammatory drugs in vitro, the need for animal experiments could be reduced and pulmonary drug development accelerated.
  • Redispersible Spray-Dried Powder Containing Nanoencapsulated Curcumin: the Drying Process Does Not Affect Neuroprotection In vitro.

    de Andrade, Diego Fontana; Vukosavljevic, Branko; Hoppe, Juliana Bender; Pohlmann, Adriana Raffin; Guterres, Sílvia Stanisçuaski; Windbergs, Maike; Külkamp-Guerreiro, Irene; Salbego, Christianne Gazzana; Beck, Ruy Carlos Ruver; HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany.;TWINCORE, Zentrum für experimentelle und klinische Infektionsforschung GmbH,Feodor-Lynen Str. 7, 30625 Hannover, Germany. (Springer, 2019-08-12)
    A redispersible spray-dried formulation containing curcumin-loaded, lipid-core nanocapsules (LNC-C) was developed for oral administration. The neuroprotective activity of curcumin after the spray-drying process was evaluated in vitro. The spray-dried powder (SD-LNC-C) was produced using a drying adjuvant composed of a blend of maltodextrin and L-leucine (90:10 w/w). Acceptable process yield (~ 70%) and drug content (6.5 ± 0.2 mg g-1) were obtained. SD-LNC-C was formed by smooth, spherical-shaped particles, and confocal Raman analysis indicated the distribution of the LNC-C on the surface of the leucine/maltodextrin agglomerates. The surface of the agglomerates was formed by a combination of LNC-C and adjuvants, and laser diffraction showed that SD-LNC-C had adequate aqueous redispersion, with no loss of controlled drug release behaviour of LNC-C. The in vitro curcumin activity against the lipopolysaccharide (LPS)-induced proinflammatory response in organotypic hippocampal slice cultures was evaluated. Both formulations (LNC-C and SD-LNC-C) reduced TNF-α to similar levels. Therefore, neuroprotection of curcumin in vitro may be improved by nanoencapsulation followed by spray-drying, with no loss of this superior performance. Hence, the redispersible spray-dried powder proposed here represents a suitable approach for the development of innovative nanomedicines containing curcumin for the prevention/treatment of neurodegenerative diseases.
  • Analysis and optimization of two film-coated tablet production processes by computer simulation: A case study

    Hering, Stefanie; Schäuble, Nico; Buck, Thomas M.; Loretz, Brigitta; Rillmann, Thomas; Stieneker, Frank; Lehr, Claus Michael; HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (MDPI, 2021-01-01)
    Increasing regulatory demands are forcing the pharmaceutical industry to invest its available resources carefully. This is especially challenging for small- and middle-sized companies. Computer simulation software like FlexSim allows one to explore variations in production processes without the need to interrupt the running process. Here, we applied a discrete-event simulation to two approved film-coated tablet production processes. The simulations were performed with FlexSim (FlexSim Deutschland—Ingenieurbüro für Simulationsdienstleistung Ralf Gruber, Kirchlengern, Germany). Process visualization was done using Cmap Tools (Florida Institute for Human and Machine Cognition, Pensacola, FL, USA), and statistical analysis used MiniTab® (Minitab GmbH, Munich, Germany). The most critical elements identified during model building were the model logic, operating schedule, and processing times. These factors were graphically and statistically verified. To optimize the utilization of employees, three different shift systems were simulated, thereby revealing the advantages of two-shift and one-and-a-half-shift systems compared to a one-shift system. Without the need to interrupt any currently running production processes, we found that changing the shift system could save 50–53% of the campaign duration and 9–14% of the labor costs. In summary, we demonstrated that FlexSim, which is mainly used in logistics, can also be advantageously implemented for modeling and optimizing pharmaceutical production processes.
  • A hydrogel-based assay for the fast prediction of antibiotic accumulation in Gram-negative bacteria.

    Richter, Robert; Kamal, Mohamed A M; García-Rivera, Mariel A; Kaspar, Jerome; Junk, Maximilian; Elgaher, Walid A M; Srikakulam, Sanjay Kumar; Gress, Alexander; Beckmann, Anja; Grißmer, Alexander; et al. (Elsevier, 2020-11-02)
    The pipeline of antibiotics has been for decades on an alarmingly low level. Considering the steadily emerging antibiotic resistance, novel tools are needed for early and easy identification of effective anti-infective compounds. In Gram-negative bacteria, the uptake of anti-infectives is especially limited. We here present a surprisingly simple in vitro model of the Gram-negative bacterial envelope, based on 20% (w/v) potato starch gel, printed on polycarbonate 96-well filter membranes. Rapid permeability measurements across this polysaccharide hydrogel allowed to correctly predict either high or low accumulation for all 16 tested anti-infectives in living Escherichia coli. Freeze-fracture TEM supports that the macromolecular network structure of the starch hydrogel may represent a useful surrogate of the Gram-negative bacterial envelope. A random forest analysis of in vitro data revealed molecular mass, minimum projection area, and rigidity as the most critical physicochemical parameters for hydrogel permeability, in agreement with reported structural features needed for uptake into Gram-negative bacteria. Correlating our dataset of 27 antibiotics from different structural classes to reported MIC values of nine clinically relevant pathogens allowed to distinguish active from nonactive compounds based on their low in vitro permeability specifically for Gram-negatives. The model may help to identify poorly permeable antimicrobial candidates before testing them on living bacteria.
  • Decoding (patho-)physiology of the lung by advanced in vitro models for developing novel anti-infectives therapies.

    Montefusco-Pereira, Carlos Victor; Carvalho-Wodarz, Cristiane de Souza; Seeger, Johanna; Kloft, Charlotte; Michelet, Robin; Lehr, Claus-Michael; HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (Elsevier, 2020-11-21)
    Advanced lung cell culture models provide physiologically-relevant and complex data for mathematical models to exploit host-pathogen responses during anti-infective drug testing.
  • Synthesis and Biopharmaceutical Characterization of Amphiphilic Squalenyl Derivative Based Versatile Drug Delivery Platform.

    Ho, Duy-Khiet; Christmann, Rebekka; Murgia, Xabier; de Rossi, Chiara; Frisch, Sarah; Koch, Marcus; Schaefer, Ulrich F; Loretz, Brigitta; Desmaele, Didier; Couvreur, Patrick; et al. (Frontiers, 2020-10-19)
    Hepatitis C virus (HCV) has no animal reservoir, infecting only humans. To investigate species barrier determinants limiting infection of rodents, murine liver complementary DNA library screening was performed, identifying transmembrane proteins Cd302 and Cr1l as potent restrictors of HCV propagation. Combined ectopic expression in human hepatoma cells impeded HCV uptake and cooperatively mediated transcriptional dysregulation of a noncanonical program of immunity genes. Murine hepatocyte expression of both factors was constitutive and not interferon inducible, while differences in liver expression and the ability to restrict HCV were observed between the murine orthologs and their human counterparts. Genetic ablation of endogenous Cd302 expression in human HCV entry factor transgenic mice increased hepatocyte permissiveness for an adapted HCV strain and dysregulated expression of metabolic process and host defense genes. These findings highlight human-mouse differences in liver-intrinsic antiviral immunity and facilitate the development of next-generation murine models for preclinical testing of HCV vaccine candidates.
  • Editorial EJPB - Biobarriers 2018.

    Fuhrmann, Gregor; Loretz, Brigitta; Schneider-Daum, Nicole; Lehr, Claus-Michael; HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (Elsevier, 2020-11-02)
    [No abstract available]
  • Controlling Supramolecular Structures of Drugs by Light.

    Wiest, Johannes; Kehrein, Josef; Saedtler, Marco; Schilling, Klaus; Cataldi, Eleonora; Sotriffer, Christoph A; Holzgrabe, Ulrike; Rasmussen, Tim; Böttcher, Bettina; Cronin-Golomb, Mark; et al. (American Chemical Society (ACS), 2020-10-29)
    Controlling physicochemical properties of light-unresponsive drugs, by light, prima facie, a paradox approach. We expanded light control by ion pairing light-unresponsive salicylate or ibuprofen to photoswitchable azobenzene counterions, thereby reversibly controlling supramolecular structures, hence the drugs' physicochemical and kinetic properties. The resulting ion pairs photoliquefied into room-temperature ionic liquids under ultraviolet light. Aqueous solutions showed trans-cis-dependent supramolecular structures under a light with wormlike aggregates decomposing into small micelles and vice versa. Light control allowed for permeation through membranes of cis-ibuprofen ion pairs within 12 h in contrast to the trans ion pairs requiring 72 h. In conclusion, azobenzene ion-pairing expands light control of physicochemical and kinetic properties to otherwise light-unresponsive drugs.
  • Micro-rheological properties of lung homogenates correlate with infection severity in a mouse model of Pseudomonas aeruginosa lung infection.

    Murgia, Xabier; Kany, Andreas M; Herr, Christian; Ho, Duy-Khiet; de Rossi, Chiara; Bals, Robert; Lehr, Claus-Michael; Hirsch, Anna K H; Hartmann, Rolf W; Empting, Martin; et al. (Nature publishing group (NPG), 2020-10-05)
    Lung infections caused by Pseudomonas aeruginosa pose a serious threat to patients suffering from, among others, cystic fibrosis, chronic obstructive pulmonary disease, or bronchiectasis, often leading to life-threatening complications. The establishment of a chronic infection is substantially related to communication between bacteria via quorum-sensing networks. In this study, we aimed to assess the role of quorum-sensing signaling molecules of the Pseudomonas quinolone signal (PQS) and to investigate the viscoelastic properties of lung tissue homogenates of PA-infected mice in a prolonged acute murine infection model. Therefore, a murine infection model was successfully established via intra-tracheal infection with alginate-supplemented Pseudomonas aeruginosa NH57388A. Rheological properties of lung homogenates were analyzed with multiple particle tracking (MPT) and quorum-sensing molecules were quantified with LC-MS/MS. Statistical analysis of bacterial load and quorum-sensing molecules showed a strong correlation between these biomarkers in infected lungs. This was accompanied by noticeable changes in the consistency of lung homogenates with increasing infection severity. Furthermore, viscoelastic properties of the lung homogenates strongly correlated with bacterial load and quorum sensing molecules. Considering the strong correlation between the viscoelasticity of lung homogenates and the aforementioned biomarkers, the viscoelastic properties of infected lungs might serve as reliable new biomarker for the evaluation of the severity of P. aeruginosa infections in murine models.
  • Towards a Continuous Manufacturing Process of Protein-Loaded Polymeric Nanoparticle Powders.

    Schiller, Stefan; Hanefeld, Andrea; Schneider, Marc; Lehr, Claus-Michael; HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (Springer, 2020-10-06)
    To develop a scalable and efficient process suitable for the continuous manufacturing of poly(lactic-co-glycolic acid) (PLGA) nanoparticles containing ovalbumin as the model protein. PLGA nanoparticles were prepared using a double emulsification spray-drying method. Emulsions were prepared using a focused ultrasound transducer equipped with a flow cell. Either poly(vinyl alcohol) (PVA) or poloxamer 407 (P-407) was used as a stabilizer. Aliquots of the emulsions were blended with different matrix excipients and spray dried, and the yield and size of the resuspended nanoparticles was determined and compared against solvent displacement. Nanoparticle sizes of spray-dried PLGA/PVA emulsions were independent of the matrix excipient and comparable with sizes from the solvent displacement method. The yield of the resuspended nanoparticles was highest for emulsions containing trehalose and leucine (79%). Spray drying of PLGA/P-407 emulsions led to agglomerated nanoparticles independent of the matrix excipient. PLGA/P-407 nanoparticles pre-formed by solvent displacement could be spray dried with limited agglomeration when PVA was added as an additional stabilizer. A comparably high and economically interesting nanoparticle yield could be achieved with a process suitable for continuous manufacturing. Further studies are needed to understand the robustness of a continuous process at commercial scale.
  • Human airway mucus alters susceptibility of Pseudomonas aeruginosa biofilms to tobramycin, but not colistin.

    Müller, Laura; Murgia, Xabier; Siebenbürger, Lorenz; Börger, Carsten; Schwarzkopf, Konrad; Sewald, Katherina; Häussler, Susanne; Braun, Armin; Lehr, Claus-Michael; Hittinger, Marius; et al.
    Objectives: In the context of cystic fibrosis, Pseudomonas aeruginosa biofilms often develop in the vicinity of airway mucus, which acts as a protective physical barrier to inhaled matter. However, mucus can also adsorb small drug molecules administered as aerosols, including antibiotics, thereby reducing their bioavailability. The efficacy of antibiotics is typically assessed by determining the MIC using in vitro assays. This widespread technique, however, does not consider either bacterial biofilm formation or the influence of mucus, both of which may act as diffusion barriers, potentially limiting antibiotic efficacy. Methods: We grew P. aeruginosa biofilms in the presence or absence of human tracheal mucus and tested their susceptibility to tobramycin and colistin. Results: A significant reduction of tobramycin efficacy was observed when P. aeruginosa biofilms were grown in the presence of mucus compared with those grown in the absence of mucus. Diffusion of tobramycin through mucus was reduced; however, this reduction was more pronounced in biofilm/mucus mixtures, suggesting that biofilms in the presence of mucus respond differently to antibiotic treatment. In contrast, the influence of mucus on colistin efficacy was almost negligible and no differences in mucus permeability were observed. Conclusions: These findings underline the important role of mucus in the efficacy of anti-infective drugs.
  • Itaconic Acid Increases the Efficacy of Tobramycin against Biofilms.

    Ho, Duy-Khiet; de Rossi, Chiara; Loretz, Brigitta; Murgia, Xabier; Lehr, Claus-Michael; HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (MDPI, 2020-07-22)
    The search for novel therapeutics against pulmonary infections, in particular Pseudomonas aeruginosa (PA) biofilm infections, has been intense to deal with the emergent rise of antimicrobial resistance. Despite the numerous achievements in drug discovery and delivery strategies, only a limited number of therapeutics reach the clinic. To allow a timely preclinical development, a formulation should be highly effective, safe, and most importantly facile to produce. Thus, a simple combination of known actives that enhances the therapeutic efficacy would be a preferential choice compared to advanced drug delivery systems. In this study, we propose a novel combination of an anti-inflammatory agent-itaconic acid (itaconate, IA)-and an approved antibiotic-tobramycin (Tob) or ciprofloxacin (Cipro). The combination of Tob and IA at a molar ratio of 1:5 increased the biofilm eradicating efficacy in the strain PA14 wild type (wt) by ~4-fold compared to Tob alone. In contrast, such effect was not observed for the combination of IA with Cipro. Subsequent studies on the influence of IA on bacterial growth, pyocyanin production, and Tob biofilm penetration indicated that complexation with IA enhanced the transport of Tob through the biofilm. We recommend the simple and effective combination of Tob:IA for further testing in advanced preclinical models of PA biofilm infections.

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