@article{RiadZlotosHolzgrabe2015,
  author    = {Riad, Noura M. and Zlotos, Darius P. and Holzgrabe, Ulrike},
  title     = {Crystal structure of 5,11-dihydropyrido[2,3-b][1,4]benzodiazepin-6-one.},
  series = {Acta Crystallographica Section E Crystallographic Communications},
  volume    = {E71},
  journal   = {Acta Crystallographica Section E Crystallographic Communications},
  doi       = {10.1107/S2056989015006817},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-149627},
  pages     = {o304-o305},
  year      = {2015},
  abstract  = {The title compound, C\(_{12}\)H\(_{9}\)N\(_{3}\)O, is an inter­mediate in the synthesis of the muscarinic M2 receptor antagonist AFDX-384. The seven-membered ring adopts a boat conformation and the dihedral angle between the planes of the aromatic rings is 41.51 (9)°. In the crystal, mol­ecules are linked into [001] chains of alternating inversion dimers formed by pairs of N-H・・・O hydrogen bonds and pairs of N-H・・・N hydrogen bonds. In both cases, R\(_{2}\)\(^{2}\)(8) loops are generated.},
  language  = {en}
}
@article{ChenWernerJavadietal.2015,
  author    = {Chen, Xinyu and Werner, Rudolf A. and Javadi, Mehrbod S. and Maya, Yoshifumi and Decker, Michael and Lapa, Constantin and Herrmann, Ken and Higuchi, Takahiro},
  title     = {Radionuclide imaging of neurohormonal system of the heart},
  series = {Theranostics},
  volume    = {5},
  journal   = {Theranostics},
  number    = {6},
  doi       = {10.7150/thno.10900},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-149205},
  pages     = {545-558},
  year      = {2015},
  abstract  = {Heart failure is one of the growing causes of death especially in developed countries due to longer life expectancy. Although many pharmacological and instrumental therapeutic approaches have been introduced for prevention and treatment of heart failure, there are still limitations and challenges. Nuclear cardiology has experienced rapid growth in the last few decades, in particular the application of single photon emission computed tomography (SPECT) and positron emission tomography (PET), which allow non-invasive functional assessment of cardiac condition including neurohormonal systems involved in heart failure; its application has dramatically improved the capacity for fundamental research and clinical diagnosis. In this article, we review the current status of applying radionuclide technology in non-invasive imaging of neurohormonal system in the heart, especially focusing on the tracers that are currently available. A short discussion about disadvantages and perspectives is also included.},
  language  = {en}
}
@article{FirdessaGoodAmstaldenetal.2015,
  author    = {Firdessa, Rebuma and Good, Liam and Amstalden, Maria Cecilia and Chindera, Kantaraja and Kamaruzzaman, Nor Fadhilah and Schultheis, Martina and R{\"o}ger, Bianca and Hecht, Nina and Oelschlaeger, Tobias A. and Meinel, Lorenz and L{\"u}hmann, Tessa and Moll, Heidrun},
  title     = {Pathogen- and host-directed antileishmanial effects mediated by polyhexanide (PHMB)},
  series = {PLoS Neglected Tropical Diseases},
  volume    = {9},
  journal   = {PLoS Neglected Tropical Diseases},
  number    = {10},
  doi       = {10.1371/journal.pntd.0004041},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148162},
  pages     = {e0004041},
  year      = {2015},
  abstract  = {Background Cutaneous leishmaniasis (CL) is a neglected tropical disease caused by protozoan parasites of the genus Leishmania. CL causes enormous suffering in many countries worldwide. There is no licensed vaccine against CL, and the chemotherapy options show limited efficacy and high toxicity. Localization of the parasites inside host cells is a barrier to most standard chemo- and immune-based interventions. Hence, novel drugs, which are safe, effective and readily accessible to third-world countries and/or drug delivery technologies for effective CL treatments are desperately needed. Methodology/Principal Findings Here we evaluated the antileishmanial properties and delivery potential of polyhexamethylene biguanide (PHMB; polyhexanide), a widely used antimicrobial and wound antiseptic, in the Leishmania model. PHMB showed an inherent antileishmanial activity at submicromolar concentrations. Our data revealed that PHMB kills Leishmania major (L. major) via a dual mechanism involving disruption of membrane integrity and selective chromosome condensation and damage. PHMB's DNA binding and host cell entry properties were further exploited to improve the delivery and immunomodulatory activities of unmethylated cytosine-phosphate-guanine oligodeoxynucleotides (CpG ODN). PHMB spontaneously bound CpG ODN, forming stable nanopolyplexes that enhanced uptake of CpG ODN, potentiated antimicrobial killing and reduced host cell toxicity of PHMB. Conclusions Given its low cost and long history of safe topical use, PHMB holds promise as a drug for CL therapy and delivery vehicle for nucleic acid immunomodulators.},
  language  = {en}
}
@phdthesis{Merget2015,
  author    = {Merget, Benjamin},
  title     = {Computational methods for assessing drug-target residence times in bacterial enoyl-ACP reductases and predicting small-molecule permeability for the \(Mycobacterium\) \(tuberculosis\) cell wall},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-127386},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {\textbf{Molecular Determinants of Drug-Target Residence Times of Bacterial Enoyl-ACP Reductases.} Whereas optimization processes of early drug discovery campaigns are often affinity-driven, the drug-target residence time \$t_R\$ should also be considered due to an often strong correlation with \textit{in vivo} efficacy of compounds. However, rational optimization of \$t_R\$ is not straightforward and generally hampered by the lack of structural information about the transition states of ligand association and dissociation. The enoyl-ACP reductase FabI of the fatty acid synthesis (FAS) type II is an important drug-target in antibiotic research. InhA is the FabI enzyme of \textit{Mycobacterium tuberculosis}, which is known to be inhibited by various compound classes. Slow-onset inhibition of InhA is assumed to be associated with the ordering of the most flexible protein region, the substrate binding loop (SBL). Diphenylethers are one class of InhA inhibitors that can promote such SBL ordering, resulting in long drug-target residence times. Although these inhibitors are energetically and kinetically well characterized, it is still unclear how the structural features of a ligand affect \$t_R\$. Using classical molecular dynamics (MD) simulations, recurring conformational families of InhA protein-ligand complexes were detected and structural determinants of drug-target residence time of diphenyl\-ethers with different kinetic profiles were described. This information was used to deduce guidelines for efficacy improvement of InhA inhibitors, including 5'-substitution on the diphenylether B-ring. The validity of this suggestion was then analyzed by means of MD simulations. Moreover, Steered MD (SMD) simulations were employed to analyze ligand dissociation of diphenylethers from the FabI enzyme of \textit{Staphylococcus aureus}. This approach resulted in a very accurate and quantitative linear regression model of the experimental \$ln(t_R)\$ of these inhibitors as a function of the calculated maximum free energy change of induced ligand extraction. This model can be used to predict the residence times of new potential inhibitors from crystal structures or valid docking poses. Since correct structural characterization of the intermediate enzyme-inhibitor state (EI) and the final state (EI*) of two-step slow-onset inhibition is crucial for rational residence time optimization, the current view of the EI and EI* states of InhA was revisited by means of crystal structure analysis, MD and SMD simulations. Overall, the analyses affirmed that the EI* state is a conformation resembling the 2X23 crystal structure (with slow-onset inhibitor \textbf{PT70}), whereas a twist of residues Ile202 and Val203 with a further opened helix \$\alpha 6\$ corresponds to the EI state. Furthermore, MD simulations emphasized the influence of close contacts to symmetry mates in the SBL region on SBL stability, underlined by the observation that an MD simulation of \textbf{PT155} chain A with chain B' of a symmetry mate in close proximity of the SBL region showed significantly more stable loops, than a simulation of the tetrameric assembly. Closing Part I, SMD simulations were employed which allow the delimitation of slow-onset InhA inhibitors from rapid reversible ligands. \textbf{Prediction of \textit{Mycobacterium tuberculosis} Cell Wall Permeability.} The cell wall of \textit{M. tuberculosis} hampers antimycobacterial drug design due to its unique composition, providing intrinsic antibiotic resistance against lipophilic and hydrophilic compounds. To assess the druggability space of this pathogen, a large-scale data mining endeavor was conducted, based on multivariate statistical analysis of differences in the physico-chemical composition of a normally distributed drug-like chemical space and a database of antimycobacterial--and thus very likely permeable--compounds. The approach resulted in the logistic regression model MycPermCheck, which is able to predict the permeability probability of small organic molecules based on their physico-chemical properties. Evaluation of MycPermCheck suggests a high predictive power. The model was implemented as a freely accessible online service and as a local stand-alone command-line version. Methodologies and findings from both parts of this thesis were combined to conduct a virtual screening for antimycobacterial substances. MycPermCheck was employed to screen the chemical permeability space of \textit{M. tuberculosis} from the entire ZINC12 drug-like database. After subsequent filtering steps regarding ADMET properties, InhA was chosen as an exemplary target. Docking to InhA led to a principal hit compound, which was further optimized. The quality of the interaction of selected derivatives with InhA was subsequently evaluated using MD and SMD simulations in terms of protein and ligand stability, as well as maximum free energy change of induced ligand egress. The results of the presented computational experiments suggest that compounds with an indole-3-acethydrazide scaffold might constitute a novel class of InhA inhibitors, worthwhile of further investigation.},
  subject      = {Computational chemistry},
  language  = {en}
}
@phdthesis{Widmer2015,
  author    = {Widmer, Toni},
  title     = {Lowering lattice forces in drug substance crystals to improve dissolution and solubility},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-126232},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {Lattice forces are based on the attraction between the single moieties of molecules. The strength of lattice forces has an impact on the solid state and related physical properties such as melting point, boiling point, vapor pressure solvation and solubility. For solvation to occur, energy is required to break the lattice forces attracting ions and molecules among themselves. The energy for breaking up the attraction between the molecules is gained from the energy released when ions or molecules of the lattice associate with molecules of the solvent. Solubility is therefore, directly linked to the energy which is required to break the lattice forces and the energy which is liberated by solvation of the molecules or ions. Based on this relation, the lattice forces in two acidic compounds and a neutral compound were subsequently lowered by different approaches with the intention to increase the solubility, supersaturation, and dissolution rate. The conversion to an ionic liquid and the embedding of the compound in a pH-sensitive matrix in an amorphous state were investigated with an acidic compound and its pro-drug. The tetrabutylphosphonium (TBPH) salt showed the most promising properties among the tested counter ions. It alters the properties of the compound from a highly crystalline physicochemical state to an amorphous readily soluble material showing supersaturation in a wider pH range and higher solubility than the sodium and potassium salts. A solid dispersion approach was developed in parallel. Solid dispersions with two different pH-sensitive polymers and different drug load were prepared by lyophilization to determine the miscibility of the compound and the polymer by differential scanning calorimetry (DSC). A miscibility of 50\% of the amorphous acid with the pH-sensitive Eudragit L100-55 matrix and a miscibility of 40\% with hydroxypropyl methylcellulose acetate succinate (HPMC-AS) was found. Both approaches, the TBPH salt and the solid dispersion based on the pH-sensitive Eudragit L100-55 were tested in vivo. The TBPH salt was dosed in a buffered solution to prevent precipitation in the acidic stomach pH. This resulted in BAV higher than the crystalline suspension but lower than the solid dispersion. There were no acute toxicology effects seen. Thus, TBPH was considered safe for further studies. The TBPH salts were very hygroscopic, sticky and prone to precipitation as free compound when exposed to low pH when simulating the passage through the stomach. Thus, the principle of the ionic liquid was combined with the principle of an amorphous solid dispersion. This mitigated the risk of precipitation of the TBPH salt during the passage of the stomach. Also delinquency upon open storage was improved by embedding the TBPH salt in a pH-sensitive polymer. Dissolution tests mimicking the pH gradient in the gastro intestinal tract confirmed the protective properties of the pH-sensitive polymer matrices against recrystallization at low stomach pH in vitro. Furthermore, supersaturation at pH ranges relevant in the intestines of preclinical species or humans was observed. The TBPH solid dispersion showed superior supersaturation behavior in vitro compared to the free acid in pH-sensitive matrix. However, equally increased bioavailability (BAV) was observed when the amorphous solid dispersion contained the free acid form or the TBPH salt. Absorption seemed to be so fast that the short in vitro supersaturation observed for the free from in pH-sensitive matrix was already sufficient for complete absorption within 15 - 30 minutes. This is in accordance with the short tmax of around 15 - 30 minutes after oral application of the low lattice force principles. The pharmacokinetic (PK) profile became the main focus of further optimization as the BAV was maximized already. Early maximal plasma concentration (tmax) went along with high maximal plasma concentration (Cmax) for the low lattice force principles. Central nervous system related side effects as consequence of the PK profile with such a high Cmax were likely to happen and therefore, the formulation principles were modified to maintain the doubled BAV and reduce the observed Cmax. Additionally, the compound showed a short half-life requiring a two times daily dose, which is suboptimal for a chronic treatment. The amorphous acid in pH-matrix showed a modified PK profile when dosed in a hydrogel but not in an oleo gel. Surprisingly, administration of the TBPH salt in pH-matrix suspended in oil showed a massive delay of the tmax to 8 hours and a reduction of Cmax by factor 2 - 3 with unchanged good BAV when administered as a suspension in oil without increased viscosity. TBPH salt solution with a high viscosity resulted in the same PK profile as when administered without increased viscosity. The animal model was changed from rat to dog. The dose was limited to 15 mg/dog since they reacted much more sensitively to the drug. BAV at this dose level was 100\% for the crystalline suspension already, thus the focus of this study was not increasing BAV but to achieve prolonged and/or delayed exposure using different formulation principles elaborated in rats before. An immediate release formulation of 3 mg was combined with a delayed/modified release principle containing 12 mg of the compound. An additional study arm was conducted with a remote controlled device programmed to deliver a first dose of 3 mg instantaneously after passing the stomach and a second dose of 12 mg when entering the caecum. The tmax remained short for all formulation principles and it seemed that delayed and modified release lead to BAV reduction. The modified PK profiles could not be translated to an oral dog model which endorsed the hypothesis of an absorption window; however, the in vitro results could be translated to a dog model for colonic absorption. A nanosuspension of the crystalline compound, the TBPH salt in pH-matrix and the TBPH salt of the pro-drug of the compound were administered rectally to determine colonic absorption. The nanosuspension showed exposure around the limit of quantification whereas the TBPH in pH-matrix showed 4\% BAV and the pro-drug as TBPH salt in pH-matrix resulted in 12\% BAV although the pro-drug is factor 3 less soluble. This was in line with the increased permeation of the pro-drug which was observed in the Caco2 experiments. The bioavailability was increased by using the low lattice force principles and validated the hypothesis for the acidic drug and its pro-drug in the colonic dog model. Chemical and physicochemical stability of the investigated solid dispersions was confirmed for at least 18 months at room temperature. Amorphous solid dispersions were investigated to lower lattice forces of a neutral molecule. Solid dispersions are well known from literature; however, they are not frequently used as principles for dosage forms due to limitations in physical stability and complex manufacturing processes. A viable formulation principle was developed for a neutral compound assuming that the stability of a solid dispersion with a drug load below the maximal miscibility will be better than one which exceeds the maximal miscibility. The dispersed and amorphous state of the neutral compound resulted in a higher energy level and chemical potential compared to a crystalline form implying that they are thermodynamically instable and sensitive to recrystallization. This was confirmed by the fast recrystallization of an amorphous solid dispersion made from HPMC with 50\% drug load which recrystallized within a few days. Solid dispersions with different drug loads in different polymers and in polymer mixtures were prepared by lyophilization. The miscibility of the compound and the polymer was determined by DSC as the miscibility is a surrogate for maximal stable drugload of the solid dispersion. HPMC was found to be miscible with 20\% compound confirming the instability of the 50\% HPMC solid dispersion observed earlier. Based on dosing needs, a miscibility/drug load of at least 30\% was mandatory because of the dosing requirements to dose less than 1500 mg of final formulation. This was considered as maximal swallowable volume for later clinical development. Thus, all systems with a miscibility higher or equal to 30\% drug in polymer were evaluated in an in vitro dissolution test and ranked in comparison with amorphous pure compound, crystalline compound and a 20\% drug load solid dispersion made from HPMC. The HPMC based solid dispersion which gave good exposure in previous in vivo experiments did not support the high drugload that was needed. Therefore, similar in vitro behavior of this solid dispersion should result in similar in vivo performance. The polyvinylpyrrolidone (PVP) based solid dispersions scored with high drug load and medium initial kinetic solubility. The Soluplus based solid dispersion offer lower drug load and slightly lower initial kinetic solubility, but showed an extended supersaturation. The 4 best performing systems were evaluated in rats. They resulted in a short Tmax of 15 minutes and BAV higher than 85\% indicating fast and complete absorption. The reference HPMC based solid dispersion with a drug load of 20\% showed 65\% BAV. This showed that higher drug loads were feasible and did not limit absorption in this animal model. Since the estimated human dose required a higher formulation density than obtained from lyophilization or spray drying, melt extrusion of the solid dispersion was considered to be the most adequate technology. The process temperature needed to be below 200 °C as this value represents the degradation temperature of the polymers. It was investigated by differential scanning calorimetry whether the compound can be mixed with the molten polymer. None of the polymers could dissolve the crystalline compound below the degradation point of the polymer. The temperature had to be increased to 260 °C until the compound was molten together to a monophasic system with polymer. This resulted in degradation of the polymers. Therefore, different plasticizers and small organic molecules with similar functional groups as the compound were investigated on their ability to reduce the melting point of the mixture of polymer and compound. Positive results were obtained with several small molecules. Based on a literature review, nicotinamide had the least concerning pharmaceutical activities and was chosen for further development. Solid dispersions with the same composition as the ones tested in rat were prepared with 9\% nicotinamide as softener. Extrusion without nicotinamide was not possible at 135 °C or at 170 °C whereas the addition of 9\% nicotinamide led to a homogenous extrudate when processed at 135 °C. The solid state of the extrudates was not molecularly dispersed but the compound was in a crystalline state. They could not reach the in vitro performance observed for the lyophilized solid dispersions with Soluplus or PVP derivatives. Nevertheless, the performances in the supersaturation assay were comparable to the HPMC based lyophilized solid dispersion. The Soluplus and PVP based crystalline extrudates were evaluated in a dog PK showing that the crystalline solid dispersion does not enable BAV higher than 90\% within 24 hours after application. In parallel, the hygroscopicity of the meltextrudates was investigated by DVS and the best performing system based on Kollidon VA64 was further optimized regarding the solid state after its extrusion. The minimal process temperature to obtain a fully amorphous solid dispersion was determined by hot stage X-ray powder diffraction analysis (XRPD) and confirmed by lab scale extrusion. Addition of 9\% nicotinamide lowered the process temperature from 220 °C (without nicotinamide) to 200 °C with nicotinamide. The minimal temperature for obtaining crystal free material was independent of the nicotinamide amount as soon as it exceeded 9\%. Lowering the process temperature with nicotinamide reduced the impurity levels from 3.5\% at 220 °C to 1.1\% at 200 °C. The fully amorphous extrudates performed now better in the in vitro supersaturation assay than the lyophilized amorphous HPMC solid dispersion and the crystalline extrudates which were extruded at 135 °C. The process was up-scaled to a pilot scale extruder with alternative screw designs increasing mechanical shear forces and mixing which enabled lower process temperatures. This resulted in a maximal process temperature of 195 °C when nicotinamide was present and 205 °C without nicotinamide. However, shorter process time and reduced process temperatures (compared to the lab scale equipment) resulted in impurity levels smaller than 0.5\% for both compositions and temperatures and made the nicotinamide obsolete. The amorphous extrudates from the pilot scale extruder performed better in vitro than the crystalline extrudates from the lab scale extruder and the lyophilized HPMC solid dispersion. A comparable PK profile of the HPMC solid dispersion and the amorphous melt extruded formulation principle was anticipated from these in vitro results. This was confirmed by the pharmacokinetic profile in dogs after oral administration of the final extruded solid dispersion formulation which was equivalent with the pharmacokinetic profile of the HPMC based solid dispersion formulation. The assumption that using a drug load below the miscibility prevents the solid dispersion from recrystallization was verified at least for a limited time by a stability test at elevated temperatures for 3 months showing no change in solid state. This indicates the opportunities of the low lattice forces approach, but also showed the importance of developing principles first assuring stable solid state, performance in vitro and in vivo, tailor them in a second step based on performance and combine them with technology such as melt extrusion as third step. If these steps are done in the context of clinical needs and quality it can rationalize the development of a solid dispersion and minimalize the formulation related risks regarding biopharmacy and stability.},
  subject      = {Arzneimittel},
  language  = {en}
}
@phdthesis{Balk2015,
  author    = {Balk, Anja},
  title     = {Ionic liquids of active pharmaceutical ingredients: A novel platform addressing solubility challenges of poorly water soluble drugs},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-121925},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {Starting in the late 1990s ionic liquids (ILs) gained momentum both in academia as well as industry. ILs are defined as organic salts with a melting point below 100 °C. Active pharmaceutical ingredients (APIs) may be transferred into ILs by creating salts with a bulky counterion with a soft electron density. ILs have demonstrated the potential to tune important pharmaceutical features such as the solubility and the dissolution rate, particularly addressing the challenge of poor water soluble drugs (PWSD). Due to the tunability of ILs, modification of physico-chemical properties of APIs may be envisioned without any modifications of the chemical structure. In the first chapter the potential as well as the limitation of ILs are discussed. The chapter commences with an overview of preparation and characterization of API-ILs. Moreover, examples for pharmaceutical parameters are presented which may be affected by IL formation, including the dissolution rate, kinetic solubility or hygroscopicity as well as biopharmaceutical performance and toxicology. The impact of IL formation on those pharmaceutically relevant features is highlighted, resulting in a blueprint for a novel formulation concept to overcome PWSD challenges without the need for structural changes of the API. Within the second chapter the IL concept is detailed for one specific API - counterion combination. A poorly water soluble acidic API against migraine attacks was transformed into an IL in an effort to minimize the time to maximum plasma concentration (tmax) and optimize the overall bioavailability. These studies were conducted in parallel to a prodrug of the API for comparison of the IL strategy versus a strategy involving modification of the API's structure. A significantly longer duration of API supersaturation and a 700 fold faster dissolution rate of the IL in comparison to the free acid were obtained and the underlying mechanism was elucidated. The transepithelial absorption was determined using Caco-2 cell layers. For the IL about 3 times more substance was transported in comparison to the prodrug when substances were applied as suspensions, despite the higher permeability of the prodrug, as increased solubility of the IL exceeded this effect. Cytotoxicity of the counterion was assessed in hepatic, renal and macrophage cell lines, respectively, and IC50 values were in the upper µM / lower mM range. The outcome of the study suggested the IL approach instrumental for tuning biopharmaceutical properties, without structural changes of the API as required for preparation of prodrugs. Thus the toolbox for formulation strategies of poorly water soluble drugs could be extended by an efficient concept. The third chapter focuses on the effect of different counterions on the physico-chemical properties of an API-IL, in particular to overcome the challenge of poor water solubility. Therefore, the same poorly water soluble acidic API against migraine attacks mentioned above was combined with 36 counterions resulting in ILs and low lattice enthalpy salts (LLES). Depending on the counterions, different dissolution rates, durations of supersaturation and hygroscopicities were obtained and release profiles could be tailored from immediate to sustained release. Besides, in vitro the cytotoxicity of the counterions was assessed in three cell lines. Using molecular descriptors such as the number of hydrophobic atoms, the graph theoretical diameter and the number of positive charges of the counterion, the dissolution rate, supersaturation and hygroscopicity as well as the cytotoxicity of counterions could be adequately modeled, rendering it possible to predict properties of new LLESs. Within the forth chapter different poorly water soluble APIs were combined with the counterion tetrabutylphosphonium (TBP) studying the impact on the pharmaceutical and physical properties of the APIs. TBP-ILs and low lattice enthalpy salts were prepared of the acidic APIs Diclofenac, Ibuprofen, Ketoprofen, Naproxen, Sulfadiazine, Sulfamethoxazole and Tolbutamide. NMR and IR spectroscopy, DSC, XRPD, DVS and dissolution rate measurements, release profiles and saturation concentration measurements were used to characterize the free acids and TBP salts as compared to the corresponding sodium salts. The TBP salts as compared to the free acids displayed lower melting points and glass transition temperatures and up to 1000 times higher dissolution rates. The increase in the dissolution rate directly correlated with the salts' hygroscopicity, an aspect which is critically discussed in terms of pharmaceutical translation challenges. In summary TBP ILs of solid salts were proved instrumental to approach the challenge of poor water solubility. The outcome profiled tailor-made counterions as a powerful formulation strategy to address poor water solubility, hence bioavailability and ultimately therapeutic potential of challenging APIs. In summary, a plethora of ILs and LLESs were prepared by combination of different acidic APIs and counterions. The IL and LLESs concept was compared to conventional salt and prodrug strategies. By choice of the counterion, biopharmaceutical relevant parameters were deliberately modified and release profiles were tuned ranging from immediate to prolonged release. The impact of distinct structural counterion features controlling the dissolution, supersaturation, hygroscopicity and counterion cytotoxicity were identified, correlations were presented and predictive models were built. ILs and LLESs could be proven to be a powerful concept for the formulation of poorly water soluble acidic APIs.},
  subject      = {Arzneimittel},
  language  = {en}
}
@phdthesis{Ilko2015,
  author    = {Ilko, David},
  title     = {The use of charged aerosol detection for the analysis of excipients and active pharmaceutical ingredients},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-118377},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {The Corona® charged aerosol detector (CAD) is an aerosol-based detector first de-scribed by Dixon and Peterson in 2002. It is capable of detecting compounds inde-pendent from their physico-chemical properties presumed the analyte is sufficiently non-volatile. Consequently, the CAD is often applied to the analysis of substances that do not possess a suitable UV chromophore. Major drawbacks are however, the detector signal is non-linear and depending on the content of organic solvent in the mobile phase. This thesis tried to explore possible applications of the CAD for pharmaceutical analysis. Therefore, several substances from different compound classes were in-vestigated. Newly developed or existing methods were validated. Thus the perfor-mance of the CAD could be examined. Both assay and impurity determination were evaluated for their compliance with ICH Q2(R1) "Validation of Analytical Proce-dures" and the "Technical Guide for the Elaboration of Monographs". In the course of the establishment of reference substances at the EDQM, a generic screening method for the identification of organic and inorganic pharmaceutical counterions was needed. An HPLC-CAD method developed by Zhang et al. was therefore investigated for its suitability for pharmacopoeial purpose. Method valida-tion was performed. It was found that 23 ions could be separated and detected. Iden-tification was achieved via retention time of an authentic standard of the corre-sponding ions. Alternatively, peak assignment was performed by determination of the exact mass using TOF-MS. Ions could be quantified as impurities or for stoichi-ometric purpose. For the impurity control in topiramate, the performance characterstics of the CAD were compared to that of an ELSD. CAD was superior to ELSD in terms of repeata-bility, sensitivity and linearity. However, impurities could be quantified with satisfac-tory accuracy with both detectors. The application of the ELSD was not feasible due to non-reproducible spike peaks eluting after the principle peak in the chromatogram of the test solution. One of the impurities, topiramate impurity A (diacetonide), gave no or a vastly diminished signal in the ELSD and the CAD, respectively. It is evapo-rated during the detection process due to its relatively high vapor pressure. The re-sponse could be enhanced by a factor of nine via post-column addition of acetoni-trile and a lower nebulizer temperature. As the response of topiramate impurity A was still about thousand-fold lower than the response of all other impurities, its quantification was not feasible. Additionally, the HPLC-CAD was successfully vali-dated as an assay procedure for topiramate. There seems to be a great potential in the application of the CAD to the analysis of excipients as most compounds do not possess a suitable UV chromophore. Here, a simple and rapid HPLC-CAD method for the determination of polidocanol (PD) was developed. The method was successfully validated as a potential assay procedure for the Ph. Eur. as none is described in either of the two PD monographs. The same method was applied to the determination of the PD release from a pharmaceutical polymer matrix. A method for the determination of the fatty acid (FA) composition of polysorbate 80 (PS80) was developed and validated. Using the CAD and mass spectrometry, we were able to identify two new FAs in 16 batches from four manufacturers. All batch-es complied with pharmacopoeial specification. Furthermore, the overall composi-tion of the different PS80 species ("fingerprinting") and the peroxide content were determined. In addition to the chemical characterization, functionality related charac-teristics (FRCs) were determined. Correlations between chemical composition and FRCs were found. The validation data of the above mentioned methods suggests that the CAD repre-sents a viable detection technique for pharmaceutical analysis. The CAD was suffi-ciently sensitive for non-volatile analytes. Impurity control down to concentrations of 0.05 or 0.03\%, as demanded by ICH Q3A (R2), is achievable. However, the response of semi-volatile compounds may be drastically diminished. It could be confirmed that the response of the CAD is linear when the range does not exceed two orders of magnitude. Exceptions may be observed depending on the actual method setup. When the measuring range is sufficiently narrow, quantification can be done using single-point calibration which is common practice in pharmaceutical anlysis. Impuri-ties may also be quantified against a single calibration solution. However, correction factors may be needed and the accuracy is considerably lower compared to an as-say method. If a compound is to be quantified over a large concentration range, log-log transformation of the calibration curve is needed and a decreased accuracy has to be accepted.},
  subject      = {Analyse},
  language  = {en}
}
@phdthesis{Kessler2015,
  author    = {Keßler, Martina},
  title     = {Biodegradable solvent cast films and solution electrospun meshes for the prevention of postsurgical adhesions},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-129358},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {Intraperitoneal adhesions are fibrous bands that connect tissues in the peritoneal cavity that are usually separated. These adhesions form as a consequence of trauma, inflammation or surgical interventions and often result in severe consequences such as chronic pain, small bowel obstructions or female infertility. The aim of this thesis was to develop a synthetic barrier device for adhesion prevention made of modified poly(lactide) [PLA]. Solid PLA films (SurgiWrap®) are already successfully in clinical use due to the good biocompatibility and the biodegradability of the material resulting in non-toxic degradation products since lactic acid is naturally part of the metabolic circles of the human body. Considering the brittleness and stiffness of the films, the long degradation time of several months as well as the need for suturing, there is potential for optimization. Through a copolymerization with the hydrophilic poly(ethylene glycol) [PEG], a reduction of the degradation time was intendend. Moreover, the copolymerization should also lead to an improvement of the mechanical properties of the films since PEG acts as plasticizer for PLA. Linear PLA-PEG-PLA triblock copolymers as well as star-shaped PEG-PLA copolymers were synthesized via standard ring opening polymerization to tailor the barrier properties. Besides solid films, solution electrospun meshes from PLA and the synthesized PEG-PLA copolymers were investigated for a potential application as well. Since suturing of a barrier additionally induces adhesion formation, alginate coated membranes were prepared in order to achieve self-adhesiveness. With the intention to reduce infections and consequently inflammation, electrospun meshes and solvent cast films were loaded with the antibacterial drug triclosan and drug release as well as antibacterial efficacy was investigated. Mechanical tests confirmed that through the variation of the PEG content and branching the mechanical properties can be tailored and are in good accordance with the glass transition temperatures [Tg] of the polymers. Consequently, potentially adequate mechanical properties for surgical handling as well as for the performance within the patient's body were successfully achieved. Degradation studies revealed that the degradation time was significantly shorter for PEG-PLA membranes than for PLA films and with an appropriate PEG content could be adjusted to the intended time frame. Cell adhesion and viability tests confirmed the non-toxicity of the clinically used PLA films as well as of PEG-PLA films and meshes. With a bioadhesion test the benefit of an alginate coated side towards the pure PLA film concerning self-adhesiveness was successfully demonstrated. Moreover, optical evaluations and a T-peel test of different alginate coated PLA films showed that the cohesion between the chemically different layers was distinctly enhanced by the use of an appropriate PEG-PLA mesh as intermediate cohesion promoting layer. In in vitro release studies with triclosan loaded films a higher release was determined for PEG-PLA than for PLA films. In agar diffusion tests a higher and longer inhibition of staphylococcus aureus growth was observed confirming the release results. Moreover, drug loaded meshes (especially drug loaded after electrospinning) showed enhanced and elongated bacterial inhibition in comparison to films.},
  subject      = {Polymere},
  language  = {en}
}
@phdthesis{Glaser2015,
  author    = {Glaser, Jan},
  title     = {Antileishmanial compounds from Nature - Elucidation of the active principles of an extract from Valeriana wallichii rhizomes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-129140},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {This study is dealing with the bioactivity-guided fractionation of a chloroform extract from pulverized rhizomes of Valeriana wallichii with focus on isolation and structure elucidation of the antileishmanial active principles.},
  subject      = {Leishmaniose},
  language  = {en}
}
@phdthesis{Muelek2015,
  author    = {M{\"u}lek, Melanie},
  title     = {Distribution and metabolism of constituents and metabolites of a standardized maritime pine bark extract (Pycnogenol®) in human serum, blood cells and synovial fluid of patients with severe osteoarthritis},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-128085},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {Dietary polyphenols have been related to beneficial effects on humans' health. Pycnogenol®, a dietary polyphenol-rich food supplement complies with the monograph "Maritime pine extract" in the United States Pharmacopeia (USP) and has demonstrated effects in different diseases. Several human trials concerning knee osteoarthritis have shown significant improvement of the symptoms like reducing the pain and the stiffness of the joint(s) upon intake of Pycnogenol®. After oral intake of multiple doses of Pycnogenol® previously low concentrations in the nanomolar range of monomeric extract constituents have been found in human plasma as well as a bioactive metabolite, δ-(3,4-dihydroxy-phenyl)-γ-valerolactone (M1), which is formed by the human intestinal flora from the procyanidins' catechin units. It is not clear yet which compound(s) of the complex extract is (are) mainly responsible for the described clinical effects of Pycnogenol®. To gain deeper insights into the in vivo fate of the pine bark extract the distribution of its constitutents and metabolites was closer investigated in the present thesis. Initial in vitro experiments suggested a facilitated cellular uptake of M1 into human erythrocytes, possibly via GLUT-1 transporter. For elucidating further the in vitro and in vivo metabolism of M1 in human blood cells, a metabolomic approach was performed using UPLC-ESI-qTOF-MSE analysis, which revealed a comprehensive and rapid metabolism of M1 to a variety of biotransformation products in human blood cells. Predominant metabolites were found to be conjugates of glutathione (GSH) isomers, namely M1-S-GSH and M1-N-GSH. Further sulfur-containing biotransformation products of M1 were conjugates with oxidized glutathione (M1-GSSG) and cysteine (M1-CYS) and the sulfated derivative of M1 (M1-sulfated). Other in vitro biotransformation products constituted the open-chained ester form of M1 (M1-COOH), hydroxybenzoic acid and the methylated (M1-methylated), acetylated (M1-acetylated), hydroxylated (M1-hydroxylated) and ethylated (M1-ethylated) derivatives of M1. Indeed, six of these in vitro metabolites, respectively M1-COOH, M1-sulfated, hydroxybenzoic acid, M1-S-GSH, M1-methylated and M1-acetylated, were also identified in vivo in blood cells of human volunteers after ingestion of Pycnogenol®. Related reference material was synthesized for reliable confirmation of the metabolites M1-GSH, M1-GSSG, M1-CYS and M1-COOH. In the course of a randomized controlled clinical trial patients suffering from severe osteoarthritis ingested multiple doses of 200 mg/day Pycnogenol® for three weeks before they were scheduled for an elective knee replacement surgery. Various biological specimen, respectively blood cells, synovial fluid and serum samples, were to be analyzed to investigate the distribution and disposition of possibly bioactive constituents and metabolites. Therefore, highly sensitive methods were developed using liquid chromatography tandem mass spectrometry (LC-MS/MS)- technology because of the expected low concentrations of the analytes in the related matrices. Initially, for each matrix different sample preparation techniques (protein precipitation, liquid-liquid extraction, solid phase extraction and useful combinations thereof) were compared to achieve maximum detection sensitivity of the analytes that were of highest interest, namely M1, ferulic acid and taxifolin. By comparing 32 various sample clean-up procedures in human serum, the highest recovery of the metabolite M1 was achieved using a liquid-liquid extraction with ethyl acetate and tert-butyl methyl ether at a serum pH-value of 3.2. A similar extraction method was also chosen for analyte detection in human synovial fluid after comparing 31 different sample preparation techniques. Whole blood or blood cells are difficult to handle because of their high viscosity and strong coloration. The QuEChERS (quick, easy, cheap, effective, rugged and safe) approach which was originally developed for the food safety and thus for the determination of pesticide residues in fruits and vegetables yielded the highest total recovery rate of M1 in human blood cells when assessing 18 different sample clean-up techniques. By applying the QuEChERS method for the first time for the simultaneous and highly sensitive quantification of selected polyphenols in human blood cells it was demonstrated that this fast and inexpensive technique can be applied in clinical fields for cleaning-up highly complex and thus challenging biological matrices. All developed methods for the different biological specimen were optimized to achieve maximum sensitivity of the target analytes. The determined lower limits of quantification (LLOQs) were sufficient for the quantification of the study samples. The LLOQs ranged from 113 pg/mL for taxifolin to 48 ng/mL for caffeic acid in blood cells and from 80 pg/mL for taxifolin to 3 ng/mL for caffeic acid in synovial fluid. In human serum the LLOQs even ranged down to 35 pg/mL for taxifolin and up to 8 ng/mL for caffeic acid. All analytical methods were subjected to a full validation according to current EMA and FDA guidelines and fulfilled those criteria, showing excellent performance and reliability of the developed and optimized methods. Serum, blood cells and synovial fluid samples of the osteoarthritis patients were all processed with an enzymatic incubation with ß-glucuronidase/sulfatase to hydrolyse conjugates (phase-II-metabolism) prior the actual sample preparation. Additionally, serum samples of the osteoarthritis patients were prepared without enzymatic hydrolysis to determine the individual degree of conjugation with sulfate and glucuronic acid of the analytes. All determined concentrations in the patients' samples were in the lower ng/mL range. Notably, highest total concentrations of the polyphenols were not detected in serum, in which the degree of analyte conjugation with sulfate and glucuronic acid ranged from 54.29 ± 26.77\% for catechin to 98.34 ± 4.40\% for M1. The flavonoids catechin and taxifolin mainly partitioned into blood cells, whereas the metabolite M1, ferulic and caffeic acid primarily resided in the synovial fluid. The concentration of M1 in the blood cells was low, however, this could be explained by the previously observed extensive and rapid intracellular metabolism in vitro. This was now supported by the in vivo evidence in samples of patients who received Pycnogenol® in which the open-chained ester form of M1 (M1-COOH) as well as the glutathione conjugate of M1 (M1-GSH) were identified, indicating that M1 does not accumulate in its original form in vivo. Possibly, a variety of bioactive metabolites exist which might play an important role for the clinical effects of Pycnogenol®. Although the study participants were requested to avoid polyphenol-rich food and beverages within the last two days before the blood samplings this was obviously difficult for most of the patients. Hence, no statistically significantly difference was observed in the mean polyphenol concentrations in serum, blood cells and synovial fluid between the intervention and the control group. Nevertheless, it was possible to identify marker compounds for Pycnogenol® intake under real life conditions with occasional or regular consumption of polyphenol-rich foods and beverages. Thereby, ferulic acid was found in serum samples exclusively after intake of Pycnogenol®, confirming that ferulic acid is a suitable marker of consumption of French maritime pine bark extract. Taxifolin was present in serum and synovial fluid exclusively in the intervention group indicating a role as further marker of Pycnogenol® intake. Taxifolin, ferulic acid and caffeic acid were detected in both serum and synovial fluid only in the intervention group. Moreover, the metabolite M1, taxifolin and ferulic acid were only detected simultaneously in all matrices (serum, blood cells and synovial fluid) after ingestion of Pycnogenol®. Thus, deeper insights into the distribution of bioactive constituents and metabolites of Pycnogenol® into serum, blood cells and synovial fluid after oral administration to patients with severe osteoarthritis were gained. The present study provides the first evidence that polyphenols indeed distribute into the synovial fluid of patients with osteoarthritis where they might contribute to clinical effects.},
  subject      = {Pycnogenol},
  language  = {en}
}
@phdthesis{Puhl2015,
  author    = {Puhl, Sebastian},
  title     = {Methods for protein crystal delivery: Exploring new techniques for encapsulation and controlled release},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-126371},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {More and more newly registered drugs are proteins. Although many of them suffer from instabilities in aqueous media, the most common way of protein drug administration still is the injection of a solution. Numerous protein drugs require frequent administration, but suitable controlled release systems for proteins are rare. Chapter 1 presents current advances in the field of controlled delivery of particulate protein formulations. While the main focus lies on batch crystallized proteins, amorphous particulate proteins are also discussed in this work. The reason is that, on the one hand precipitated protein particles hold some of the advantages of crystalline proteins and on the other hand the physical state of the protein may simply be unknown for many drug delivery systems or semi-crystalline particles have been used. Crystallization and precipitations methods as well as controlled delivery methods with and without encapsulation in a polymeric delivery system are summarized and critically discussed. In chapter 2 a novel way of protein crystal encapsulation by electrospinning is introduced. Electrospinning of proteins has been shown to be challenging via the use of organic solvents, frequently resulting in protein unfolding or aggregation. Encapsulation of protein crystals represents an attractive but largely unexplored alternative to established protein encapsulation techniques because of increased thermodynamic stability and improved solvent resistance of the crystalline state. We herein explore the electrospinning of protein crystal suspensions and establish basic design principles for this novel type of protein delivery system. Poly-ε-caprolactone (PCL) is an excellent polymer for electrospinning and matrix-controlled drug delivery combining optimal processability and good biocompatibility. PCL was deployed as a matrix, and lysozyme was used as a crystallizing model protein. By rational combination of lysozyme crystals with a diameter of 0.7 or 2.1 μm and a PCL fiber diameter between 1.6 and 10 μm, release within the first 24 h could be varied between approximately 10 and 100\%. Lysozyme loading of PCL microfibers between 0.5 and 5\% was achieved without affecting processability. While relative release was unaffected by loading percentage, the amount of lysozyme released could be tailored. PCL was blended with poly(ethylene glycol) and poly(lactic-co-glycolic acid) to further modify the release rate. Under optimized conditions, an almost constant lysozyme release over 11 weeks was achieved. Chapter 3 takes on the findings made in chapter 2 and further modifies the properties of the nonwovens as protein crystal delivery system. Nonwoven scaffolds consisting of poly-ε-caprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA) and polidocanol (PD), and loaded with lysozyme crystals were prepared by electrospinning. The composition of the matrix was varied and the effect of PD content in binary mixtures, and of PD and PLGA content in ternary mixtures regarding processability, fiber morphology, water sorption, swelling and drug release was studied. Binary PCL/PD blend nonwovens showed a PD-dependent increase in swelling of up to 30\% and of lysozyme burst release of up to 45\% associated with changes of the fiber morphology. Furthermore, addition of free PD to the release medium resulted in a significant increase of lysozyme burst release from pure PCL nonwovens from approximately 2\% to 35\%. Using ternary PCL/PD/PLGA blends, matrix degradation could be significantly improved over PCL/PD blends, resulting in a biphasic release of lysozyme with constant release over 9 weeks, followed by constant release with a reduced rate over additional 4 weeks. Based on these results, protein release from PCL scaffolds is improved by blending with PD due to improved lysozyme desorption from the polymer surface and PD-dependent matrix swelling. Chapter 4 gives deeper insight on lysozyme batch crystallization and shows the influences of the temperature on the precipitation excipients. Yet up to now protein crystallization in a pharmaceutical useful scale displays a challenge with crystal size and purity being important but difficult to control parameters. Some of these influences are being discussed here and a detailed description of crystallization methods and the achieved crystals are demonstrated. Therapeutic use of such protein crystals may require further modification of the protein release rate through encapsulation. Silk fibroin (SF) harvested from the cocoons of Bombyx mori is a well-established protein suitable for encapsulation of small molecules as well as proteins for controlled drug delivery. This novel polymer was deployed for as carrier for the model drug crystals. Lysozyme again was used as a crystallizable protein and the effect of process- as well as formulation parameters of batch crystallization on crystal size were investigated using statistical design of experiments. Lysozyme crystal size depended on temperature and sodium chloride and poly(ethylenglycol) concentration of precipitant solution. Under optimized conditions, lysozyme crystals in a size range of approximately 0.3 to 10 µm were obtained. Furthermore, a solid-in-oil-in-water process for encapsulation of lysozyme crystals into SF was developed. Using this process, coating of protein crystals with another protein was achieved for the first time. Encapsulation resulted in a significant reduction of dissolution rate of lysozyme crystals, leading to prolonged release over up to 24 hours.},
  subject      = {Kontrollierte Wirkstofffreisetzung},
  language  = {en}
}
@article{GlaserSchurigtSuzukietal.2015,
  author    = {Glaser, Jan and Schurigt, Uta and Suzuki, Brian M. and Caffrey, Connor R. and Holzgrabe, Ulrike},
  title     = {Anti-Schistosomal Activity of Cinnamic Acid Esters: Eugenyl},
  series = {Molecules},
  volume    = {20},
  journal   = {Molecules},
  doi       = {10.3390/molecules200610873},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125712},
  pages     = {10873-10883},
  year      = {2015},
  abstract  = {Bornyl caffeate (1) was previously isolated by us from Valeriana (V.) wallichii rhizomes and identified as an anti-leishmanial substance. Here, we screened a small compound library of synthesized derivatives 1-30 for activity against schistosomula of Schistosoma (S.) mansoni. Compound 1 did not show any anti-schistosomal activity. However, strong phenotypic changes, including the formation of vacuoles, degeneration and death were observed after in vitro treatment with compounds 23 (thymyl cinnamate) and 27 (eugenyl cinnamate). Electron microscopy analysis of the induced vacuoles in the dying parasites suggests that 23 and 27 interfere with autophagy.},
  language  = {en}
}
@article{MergetSotriffer2015,
  author    = {Merget, Benjamin and Sotriffer, Christoph A.},
  title     = {Slow-Onset Inhibition of Mycobacterium tuberculosis InhA: Revealing Molecular Determinants of Residence Time by MD Simulations},
  series = {PLoS One},
  volume    = {10},
  journal   = {PLoS One},
  number    = {5},
  doi       = {10.1371/journal.pone.0127009},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125607},
  pages     = {e0127009},
  year      = {2015},
  abstract  = {An important kinetic parameter for drug efficacy is the residence time of a compound at a drug target, which is related to the dissociation rate constant koff. For the essential antimycobacterial target InhA, this parameter is most likely governed by the ordering of the flexible substrate binding loop (SBL). Whereas the diphenyl ether inhibitors 6PP and triclosan (TCL) do not show loop ordering and thus, no slow-binding inhibition and high koff values, the slightly modified PT70 leads to an ordered loop and a residence time of 24 minutes. To assess the structural differences of the complexes from a dynamic point of view, molecular dynamics (MD) simulations with a total sampling time of 3.0 µs were performed for three ligand-bound and two ligand-free (perturbed) InhA systems. The individual simulations show comparable conformational features with respect to both the binding pocket and the SBL, allowing to define five recurring conformational families. Based on their different occurrence frequencies in the simulated systems, the conformational preferences could be linked to structural differences of the respective ligands to reveal important determinants of residence time. The most abundant conformation besides the stable EI* state is characterized by a shift of Ile202 and Val203 toward the hydrophobic pocket of InhA. The analyses revealed potential directions for avoiding this conformational change and, thus, hindering rapid dissociation: (1) an anchor group in 2'-position of the B-ring for scaffold stabilization, (2) proper occupation of the hydrophobic pocket, and (3) the introduction of a barricade substituent in 5'-position of the diphenyl ether B-ring.},
  language  = {en}
}
@article{GlaserSchultheisMolletal.2015,
  author    = {Glaser, Jan and Schultheis, Martina and Moll, Heidrun and Hazra, Banasri and Holzgrabe, Ulrike},
  title     = {Antileishmanial and Cytotoxic Compounds from Valeriana wallichii and Identification of a Novel Nepetolactone Derivative},
  series = {Molecules},
  volume    = {20},
  journal   = {Molecules},
  number    = {4},
  doi       = {10.3390/molecules20045740},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125320},
  pages     = {5740-5753},
  year      = {2015},
  abstract  = {The chloroform extract of Valeriana wallichii (V. wallichii) rhizomes was investigated to elucidate the structures responsible for reported antileishmanial activity. Besides bornyl caffeate (1, already been reported by us previously), bioassay-guided fractionation resulted in two additional cinnamic acid derivatives 2-3 with moderate leishmanicidal activity. The structure of a novel nepetolactone derivative 4 having a cinnamic acid moiety was elucidated by means of spectral analysis. To the best of our knowledge villoside aglycone (5) was isolated from this plant for the first time. The bioassay-guided fractionation yielded two new (compounds 6-7) and two known valtrates (compounds 8-9) with leishmanicidal potential against Leishmania major (L. major) promastigotes. In addition, β-bisabolol (10), α-kessyl alcohol (11), valeranone (12), bornyl isovalerate (13) and linarin-2-O-methylbutyrate (14) were identified. This is the first report on the isolation of 4'-demethylpodophyllotoxin (15), podophyllotoxin (16) and pinoresinol (17) in V. wallichii. In total thirteen known and four new compounds were identified from the extract and their cytotoxic and antileishmanial properties were evaluated.},
  language  = {en}
}
@inproceedings{HoeggerXiao2015,
  author    = {H{\"o}gger, Petra and Xiao, Jianbo},
  title     = {Abstracts of the International Symposium on Phytochemicals in Medicine and Food},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-121585},
  year      = {2015},
  abstract  = {The International Symposium on Phytochemicals in Medicine and Food (ISPMF2015), organized by the Phytochemical Society of Europe (PSE) and the Phytochemical Society of Asia (PSA), was held June 26-29, 2015, in Shanghai of China. This was the first time that a PSE meeting has been held in Asia and a PSE-PSA joint symposium provided an opportunity for communication between scientists from Europe and Asia and other continents. ISPMF2015 has been jointly sponsored by Fujian Agriculture and Forestry University, Guizhou Medical University, Shanghai Normal University, Yancheng Institute of Technology, Beijing Normal University, and Fudan University. More than 270 scientists from 48 countries attended this meeting and presented their research and opinions on phytochemistry, phytomedicine and phytoneering. The international organizing committee and scientific advisory board of ISPMF 2015 comprised of outstanding scientists from around the globe. Dr. Jianbo Xiao was the chairman of the International Organizing Committee of ISPMF2015 and moderated the open address on June 26. The organizing committee of ISPMF2015 assembled an exciting and diverse program, featuring 16 sessions including 12 plenary lectures, 20 invited talks, 55 short oral presentations, and more than 130 posters, which were dedicated to creating a podium for exchanging the latest research results in the phytochemicals for food and human health.},
  language  = {en}
}
@phdthesis{Schultz2015,
  author    = {Schultz, Isabel},
  title     = {Therapeutic systems for Insulin-like growth factor-1},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-119114},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {SUMMARY Insulin-like growth factor I (IGF-I) is a polypeptide with a molecular weight of 7.649 kDa and an anabolic potential. Thereby, IGF-I has a promising therapeutic value e.g. in muscle wasting diseases such as sarcopenia. IGF-I is mainly secreted by the liver in response to growth hormone (GH) stimulation and is rather ubiquitously found within all tissues. The effects of IGF-I are mediated by its respective IGF-I transmembrane tyrosine kinase receptor triggering the stimulation of protein synthesis, glucose uptake and the regulation of cell growth. The actions of IGF-I are modulated by six IGF binding proteins binding and transporting IGF-I in a binary or ternary complex to tissues and receptors and modulating the binding of IGF-I to its receptor. The nature of the formed complexes impacts IGF-I`s half-life, modulating the half-life between 10 minutes (free IGF-I) to 12 - 15 hours when presented in a ternary complex with IGF binding protein 3 and an acid labile subunit (ALS). Therefore, sustained drug delivery systems of free IGF-I are superficially seen as interesting for the development of controlled release profiles, as the rate of absorption is apparently and easily set slower by simple formulation as compared to the rapid rate of elimination. Thereby, one would conclude, the formulation scientist can rapidly develop systems for which the pharmacokinetics of IGF-I are dominated by the formulation release kinetics. However, the in vivo situation is more complex and as mentioned (vide supra), the half-life may easily be prolonged up to hours providing proper IGF-I complexation takes place upon systemic uptake. These and other aspects are reviewed in Chapter I, within which we introduce IGF-I as a promising therapeutic agent detailing its structure and involved receptors along with the resulting signaling pathways. We summarize the control of IGF-I pharmacokinetics in nature within the context of its complex system of 6 binding proteins to control half-life and tissue distribution. Furthermore, we describe IGF-I variants with modulated properties in vivo and originated from alternative splicing. These insights were translated into sophisticated IGF-I delivery systems for therapeutic use. Aside from safety aspects, the challenges and requirements of an effective IGF-I therapy are discussed. Localized and systemic IGF-I delivery strategies, different routes of administration as well as liquid and solid IGF-I formulations are reviewed. Effective targeting of IGF-I by protein decoration is outlined and consequently this chapter provides an interesting guidance for successful IGF-I-delivery. In Chapter II, we firstly outline the stability of IGF-I in liquid formulations with the intention to deliver the biologic through the lung and the impact of buffer type, sodium chloride concentration and pH value on IGF-I stability is presented. IGF-I integrity was preserved in histidine buffer over 4 months at room temperature, but methionine 59 oxidation (Met(o)) along with reducible dimer and trimer formation was observed in an acidic environment (pH 4.5) and using acetate buffer. Strong aggregation resulted in a complete loss of IGF-I bioactivity, whereas the potency was partly maintained in samples showing a slight aggregation and complete IGF-I oxidation. Atomization by air-jet or vibrating-mesh nebulizers yielded in limited Met(o) formation and no aggregation. The results of IGF-I nebulization experiments regarding aerosol output rate, mass median aerodynamic diameter and fine particle fraction were comparable with 0.9\% sodium chloride reference, approving the applicability of liquid IGF-I formulations for pulmonary delivery. In Chapter III we escalated the development to solid delivery systems designed for alveolar landing upon inhalation and by deploying trehalose and the newly introduced for pulmonary application silk-fibroin as carriers. Microparticles were produced using nano spray drying following analyses including IGF-I integrity, IGF-I release profiles and aerodynamic properties. In vitro transport kinetics of IGF-I across pulmonary Calu-3 epithelia were suggesting similar permeability as compared to IGF-I's cognate protein, insulin that has already been successfully administered pulmonary in clinical settings. These in vivo results were translated to an ex vivo human lung lobe model. This work showed the feasibility of pulmonary IGF-I delivery and the advantageous diversification of excipients for pulmonary formulations using silk-fibroin. Chapter IV focuses on an innovative strategy for safe and controllable IGF-I delivery. In that chapter we escalated the development to novel IGF-I analogues. The intention was to provide a versatile biologic into which galenical properties can be engineered through chemical synthesis, e.g. by site directed coupling of polymers to IGF-I. For this purpose we genetically engineered two IGF-I variants containing an unnatural amino acid at two positions, respectively, thereby integrating alkyne functions into the primary sequence of the protein. These allowed linking IGF-I with other molecules in a site specific manner, i.e. via a copper catalyzed azide-alkyne Huisgen cycloaddition (click reaction). In this chapter we mainly introduce the two IGF-I variants, detail the delivery concept and describe the optimization of the expression conditions of the IGF-I variants. In conclusion, we span from simple liquid formulations for aerolization through solid systems for tailored for maximal alveolar landing to novel engineered IGF-I analogues. Thereby, three strategies for advanced IGF-I delivery were addressed and opportunities and limitations of each were outlined. Evidence was provided that sufficiently stable and easy to manufacture formulations can be developed as typically required for first in man studies. Interestingly, solid systems - typically introduced in later stages of pharmaceutical development - were quite promising. By use of silk-fibroin as a new IGF-I carrier for pulmonary administration, a new application was established for this excipient. The demonstrated success using the ex vivo human lung lobe model provided substantial confidence that pulmonary IGF-I delivery is possible in man. Finally, this work describes the expression of two IGF-I variants containing two unnatural amino acids to implement an innovative strategy for IGF-I delivery. This genetic engineering approach was providing the fundament for novel IGF-I analogues. Ideally, the biologic is structurally modified by covalently linked moieties for the control of pharmacokinetics or for targeted delivery, e.g. into sarcopenic muscles. One future scenario is dicussed in the 'conclusion and outlook' section for which IGF-I is tagged to a protease sensitive linker peptide and this linker peptide in return is coupled to a polyethylenglykole (PEG) polymer (required to prolong the half-life). Some proteases may serve as proxy for sarcopenia such that protease upregulation in compromised muscle tissues drives cleavage of IGF-I from the PEG. Thereby, IGF-I is released at the seat of the disease while systemic side effects are minimized.},
  subject      = {Insulin-like Growth Factor I},
  language  = {en}
}
@phdthesis{Werner2015,
  author    = {Werner, Vera},
  title     = {Pharmaceutically relevant protein-protein interactions for controlled drug delivery},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-117409},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {Protein-protein interactions play a crucial role in the development of drug delivery devices for the increasingly important biologicals, including antibodies, growth factors and cytokines. The understanding thereof might offer opportunities for tailoring carriers or drug proteins specifically for this purpose and thereby allow controlled delivery to a chosen target. The possible applications range from trigger-dependent release to sustained drug delivery and possibly permanently present stimuli, depending on the anticipated mechanism. Silk fibroin (SF) is a biomaterial that is suitable as a carrier for protein drug delivery devices. It combines processability under mild conditions, good biocompatibility and stabilizing effects on incorporated proteins. As SF is naturally produced by spiders and silkworms, the understanding of this process and its major factors might offer a blueprint for formulation scientists, interested in working with this biopolymer. The natural process of silk spinning covers a fascinating versatility of aggregate states, ranging from colloidal solutions through hydrogels to solid systems. The transition among these states is controlled by a carefully orchestrated process in vivo. Major players within the natural process include the control of spatial pH throughout passage of the silk dope, the composition and type of ions, and fluid flow mechanics within the duct, respectively. The function of these input parameters on the spinning process is reviewed before detailing their impact on the design and manufacture of silk based drug delivery systems (DDS). Examples are reported including the control of hydrogel formation during storage or significant parameters controlling precipitation in the presence of appropriate salts, respectively. The review details the use of silk fibroin to develop liquid, semiliquid or solid DDS with a focus on the control of SF crystallization, particle formation, and drug-SF interaction for tailored drug load. Although we were able to show many examples for SF drug delivery applications and there are many publications about the loading of biologics to SF systems, the mechanism of interaction between both in solution was not yet extensively explored. This is why we made this the subject of our work, as it might allow for direct influence on pharmaceutical parameters, like aggregation and drug load. In order to understand the underlying mechanism for the interaction between SF and positively charged model proteins, we used isothermal titration calorimetry for thermodynamic characterization. This was supported by hydrophobicity analysis and by colloidal characterization methods including static light scattering, nanoparticle tracking analysis and zeta potential measurements. We studied the effects of three Hofmeister salts - NaCl (neutral), NaSCN (chaotropic) and Na2SO4 (cosmotropic) - and the pH on the interaction of SF with the model proteins in dependence of the ratio from one to another. The salts impacted the SF structure by stabilizing (cosmotropic) or destabilizing (chaotropic) the SF micelles, resulting in completely abolished (cosmotropic) or strongly enhanced (chaotropic) interaction. These effects were responsible for different levels of loading and coacervation when varying type of salt and its concentration. Additionally, NaCl and NaSCN were able to prolong the stability of aqueous SF solution during storage at 25°C in a preliminary study. Another approach to influence protein-protein interactions was followed by covalent modification. Interleukin-4 (IL-4) is a cytokine driving macrophages to M2 macrophages, which are known to provide anti-inflammatory effects. The possibility to regulate the polarization of macrophages to this state might be attractive for a variety of diseases, like atherosclerosis, in which macrophages are involved. As these cases demand a long-term treatment, this polarization was supposed to be maintained over time and we were planning to achieve this by keeping IL-4 permanently present in an immobilized way. In order to immobilize it, we genetically introduced an alkyne-carrying, artificial amino acid in the IL-4 sequence. This allowed access to a site-specific click reaction (Cu(I)-catalyzed Huisgen azide-alkyne cycloaddition) with an azide partner. This study was able to set the basis for the project by successful expression and purification of the IL-4 analogue and by proving the availability for the click reaction and maintained bioactivity. The other side of this project was the isolation of human monocytes and the polarization and characterization of human macrophages. The challenge here was that the majority of related research was based on murine macrophages which was not applicable to human cells and the successful work was so far limited to establishing the necessary methods. In conclusion, we were able to show two different methods that allow the influence of protein-protein interactions and thereby the possible tailoring of drug loading. Although the results were very promising for both systems, their applicability in the development of drug delivery devices needs to be shown by further studies.},
  subject      = {Protein-Protein-Wechselwirkung},
  language  = {en}
}