Design of novel drug delivery systems providing a prolonged mucosal residence time

Ziel dieser Arbeit war es, die Schleimhautverweilzeit von Wirkstoffabgabesystemen zu verlängern. Hierfür wurden zwei Strategien entwickelt, thiolysierte Polymer oder Thiomere und Zeta-Potenzial-verändernde Nanocarrier. Für die ersten Strategien wurden neue Thiomere durch Amid-, Amin- und Amidbindungsbildung unterschiedlich synthetisiert. Thiomere wurden weiters durch direkte Modifikation an Hydroxylgruppen des polymeren Rückgrats erzeugt. Darüber hinaus wurden voraktivierte und vollständig geschützte Thiomere synthetisiert, um die Reaktivität von Thiomeren zu schützen. Die neu synthetisierten Thiomere zeigten verbesserte mucoadhäsive und kohäsive Eigenschaften wie auch einen inhibierenden Effeft auf Effluxpumpen und eine gesteigerte Permeation im Vergleich zu ihren entsprechenden unmodifizierten Polymeren. Die Eigenschaften von voraktivierten Thiomeren wurden dadurch verbessert, dass sie einen Pyridylliganden Abgangsgruppen tragen. Bezüglich ihrer Anwendung erwiesen sich Thiomere als nützliche pharmazeutische Hilfsstoffe für die orale, intra-nasale, bukkale, okuläre und intraartikuläre Verabreichung. Im Falle der zweiten Strategie wurden Zeta-Potenzial-verändernde selbst emulgierende Wirkstoffabgabesysteme (SEDDS) und polymere Nanopartikel entwickelt. Verschiedene kationische Tenside und Phosphatidate wurden in SEDDS eingebaut und zeigten eine Verschiebung eines Zetapotentials nach enzymatischer Spaltung von Phosphat durch intestinale alkalische Phosphatase. Negativ geladene SEDDS zeigten eine höhere Schleimpermeation, während auf der anderen Seite positiv geladene SEDDS innerhalb des Schleimnetzes eingeschlossen wurden. Weiterhin zeigten polymere Nanopartikel, die aus phosphorylierten Polymeren und zellpenetrierenden Peptiden - Polymerkonjugaten zusammengesetzt waren, eine verbesserte Transfektionseffizienz, die hochpotenzielle Ansätze für die Genabgabe sein könnten. Daher stellte die Verwendung von sowohl thiolierten Polymeren als auch Zetapotential verändernden Nanocarriern vielversprechende Werkzeuge bereit, um die Verweilzeit auf Schleimhautmembranen zu verlängern.aim of this thesis was to prolong mucosal residence time of drug delivery systems. Two strategies, namely, thiolated polymers or thiomers and zeta potential changing nanocarriers were developed. For the first strategy, novel thiomers were differently synthesized via amide, amine and amidine bond formation. Thiomers were alternatively generated by direct modification at hydroxyl groups of polymeric backbone. Moreover, preactivated and entirely-s protected thiomers were synthesized in order to protect reactivity of thiomers. The newly synthesized thiomers showed improved mucoadhesive, cohesive, efflux pump inhibitory and permeation enhancing properties compared to their corresponding unmodified polymers. These properties of preactivated thiomers were even more pronounced due to the fact that pyridyl ligand acts as a leaving group. With regard to the application of thiomers, they were demonstrated to be useful as the pharmaceutical excipients for oral, intra-nasal, buccal, ocular and intra-articular delivery. In case of the second strategy, zeta potential changing self-emulsifying drug delivery systems (SEDDS) and polymeric nanoparticles were developed. Various cationic surfactants and phosphatidates were incorporated into SEDDS and showed a shift of a zeta potential after enzymatic cleavage of phosphate by intestinal alkaline phosphatase. Negatively charged SEDDS showed higher mucus permeation, on the other hand, positively charged SEDDS were entrapped within mucus network. Furthermore, nanoparticles composed of phosphorylated polymers and cell-penetrating peptides-polymer conjugates exhibited improved transfection efficiency that could be highly potential approaches for gene delivery. Therefore, the use of both thiolated polymers and zeta potential changing nanocarriers provided promising tools to prolong residence time on mucosal membranes.eingereicht von M.Sc. Wongsakorn SuchaoinKumulative Dissertation aus fünf ArtikelnUniversität Innsbruck, Dissertation, 2016OeBB(VLID)153945

Shape and surface properties of titanate nanomaterials influence differential cellular uptake behavior and biological responses in THP-1 cells

We investigated cellular uptake behavior and biological responses of spherical and fibrous titanate nanomaterials in human monocyte THP-1 cells. Two titanate nanofibers (TiNFs), namely TF-1 and TF-2, were synthesized from anatase TiO2 nanoparticles (TNPs) via hydrothermal treatment. The synthesized TiNFs and TNPs were thoroughly characterized for their size, crystallinity, surface area and surface pH. TF-1 (∼2 µm in length) was amorphous with an acidic surface, while TF-2 (∼7 µm in length) was brookite with a basic surface. The results demonstrated that none of these titanate nanomaterials resulted in significant cytotoxicity, even at the highest doses tested (50 µg/ml), consistent with an absence of ROS generation and lack of change of mitochondrial membrane potential. While no cytotoxic effect was found in the titanate nanomaterials, TF-2 tended to decrease the proliferation of THP-1 cells. Furthermore, TF-2 resulted in an inflammatory cytokine response, as evidenced by dramatic induction of IL-8 and TNF-α release in TF2 but not TF-1 nor TNPs. These results suggest that shape of titanate nanomaterials plays an important role in cellular internalization, while surface pH may play a prominent role in inflammatory response in THP-1 cells

Patch Testing of Thai Children with Eczema

Objective: To detect contact allergy rate and common allergens in Thai children presented with eczema. Materials and Methods: A total of 124 children, aged 1-15 years, were patch tested using a pediatric screening series of 16 allergens and relevant additional allergens. Data on clinical presentation, atopic history and test results were collected. Results: Contact allergy was found in 51 of 124 children (41.1%) presented with all forms of eczema. The common allergens were lanolin alcohol (8.9%), cocamidopropyl betaine (8.1%), nickel sulfate (7.3%), fragrance mix I (5.6%), formaldehyde (5.6%), thimerosal (5.6%), fragrance mix II (4.8%), cobalt chloride (4.0%), methylchloroisothiazolinone/methylisothiazolinone (2.4%), methylisothiazolinone (2.4%) and thiuram mix (2.4%). Nineteen of 50 atopic dermatitis patients (38%) showed positive patch test reactions. Conclusion: Allergic contact dermatitis is common in children. Both atopic and non-atopic patients can develop contact dermatitis. Patch testing should be performed in children presented with eczema regardless of contact dermatitis history

Toward Achieving Harmonization in a Nanocytotoxicity Assay Measurement Through an Interlaboratory Comparison Study

Development of reliable cell-based nanotoxicology assays is important for evaluation of potentially hazardous engineered nanomaterials. Challenges to producing a reliable assay protocol include working with nanoparticle dispersions and living cell lines, and the potential for nano-related interference effects. Here we demonstrate the use of a 96-well plate design with several measurement controls and an interlaboratory comparison study involving five laboratories to characterize the robustness of a nanocytotoxicity MTS cell viability assay based on the A549 cell line. The consensus EC50 values were 22.1 mg/L (95% confidence intervals 16.9 mg/L to 27.2 mg/L) and 52.6 mg/L (44.1 mg/L to 62.6 mg/L) for positively charged polystyrene nanoparticles for the serum-free and serum conditions, respectively, and 49.7 mu mol/L (47.5 mu mol/L to 51.5 mu mol/L) and 77.0 mu mol/L (54.3 mu mol/L to 99.4 mu mol/L) for positive chemical control cadmium sulfate for the serum-free and serum conditions, respectively. Results from the measurement controls can be used to evaluate the sources of variability and their relative magnitudes within and between laboratories. This information revealed steps of the protocol that may need to be modified to improve the overall robustness and precision. The results suggest that protocol details such as cell line ID, media exchange, cell handling, and nanoparticle dispersion are critical to ensure protocol robustness and comparability of nanocytotoxicity assay results. The combination of system control measurements and interlaboratory comparison data yielded insights that would not have been available by either approach by itself