Research Collection Doctoral Thesis Investigating Poly(styrene)-b-Poly(ethylene Oxide) Polymersomes for the Treatment and Diagnosis of Hyperammonemia Author(s): Matoori, Simon Sam Publication Date: 2019-03-03 Permanent Link: https://doi.org/10.3929/ethz-b-000328703 Rights / License: In Copyright - Non-Commercial Use Permitted This page was generated automatically upon download from the ETH Zurich Research Collection. For more information please consult the Terms of use. ETH Library DISS. ETH Nr. 25671 Investigating poly(styrene)-b-poly(ethylene oxide) polymersomes for the treatment and diagnosis of hyperammonemia Abhandlung zur Erlangung des Titels DOKTOR DER WISSENSCHAFTEN der ETH ZÜRICH (Dr. sc. ETH Zürich) vorgelegt von Simon Sam Matoori Master of Science ETH in Pharmaceutical Sciences, Master of Science ETH in Medicinal and Industrial Pharmaceutical Sciences, ETH Zürich geboren am 30.11.1988 von Zürich (ZH), Schweiz Referent: Prof. Dr. Jean-Christophe Leroux Korreferent: Prof. Dr. Peter Walde 1 Table of contents Summary ................................................................................................................................................. 4 Zusammenfassung ................................................................................................................................... 6 1. Polymersomes: from Science to science ............................................................................................. 8 1.1 Polymersome definition ................................................................................................................ 8 1.2 Historical perspective .................................................................................................................... 8 1.3 Preparation methods .................................................................................................................... 9 1.4 Drug delivery ............................................................................................................................... 10 1.5 Conclusion ................................................................................................................................... 15 1.6 Aims of the Ph.D. thesis ............................................................................................................... 16 2. Recent advances in the treatment of hyperammonemia ................................................................. 18 2.1. Introduction ................................................................................................................................ 20 2.2. Reducing ammonia generation and uptake ............................................................................... 24 2.3. Increasing ammonia removal ..................................................................................................... 32 2.4. Novel treatment approaches ..................................................................................................... 35 2.5. Conclusion .................................................................................................................................. 39 3. Investigating PS-b-PEO polymersomes for oral treatment of hyperammonemia ............................ 40 3.1. Introduction ................................................................................................................................ 40 3.2. Material and Methods ................................................................................................................ 41 PS-b-PEO polymer synthesis .......................................................................................................... 41 Liposome preparation ................................................................................................................... 42 Polymersome preparation............................................................................................................. 42 Polymer quantification .................................................................................................................. 44 Ammonia uptake in side-by-side cells ........................................................................................... 44 Ammonia uptake with microparticles ........................................................................................... 45 Dietary hydrogel experiments ....................................................................................................... 45 Lyophilization ................................................................................................................................ 46 In vivo experiments ....................................................................................................................... 46 Ammonia assays ............................................................................................................................ 47 Statistical analysis .......................................................................................................................... 48 3.3. Results and Discussion ............................................................................................................... 48 Screening of microparticle and vesicular formulations ................................................................. 48 Optimization and characterization of PS-b-PEO polymersomes ................................................... 50 Evaluation of PS-b-PEO library in simulated intestinal fluids ........................................................ 53 Stability in dietary fiber-based hydrogels ...................................................................................... 54 In vivo evaluation .......................................................................................................................... 56 2 3.4. Conclusion .................................................................................................................................. 59 4. Development of a PS-b-PEO polymersome assay ............................................................................. 60 4.1. Introduction ................................................................................................................................ 60 4.2. Materials and Methods .............................................................................................................. 62 HPTS fluorescence excitation spectra ........................................................................................... 62 PS-b-PEO polymer synthesis .......................................................................................................... 62 Polymersome preparation............................................................................................................. 63 Purification and quantification ...................................................................................................... 63 Ammonia sensing .......................................................................................................................... 63 Selectivity ...................................................................................................................................... 64 Healthy and BDL rat plasma samples ............................................................................................ 64 Statistical analysis .......................................................................................................................... 64 4.3. Results and Discussion ............................................................................................................... 65 pH-dependent fluorescence of HPTS ............................................................................................ 65 Ammonia sensing with HPTS-containing PS-b-PEO polymersomes .............................................. 65 Selectivity ...................................................................................................................................... 68 Ammonia sensing in plasma of healthy rats.................................................................................. 70 Ammonia sensing in plasma of BDL rats ....................................................................................... 70 3.4 Conclusion ................................................................................................................................... 72 5. General discussion and outlook ........................................................................................................ 73 6. List of abbreviations .......................................................................................................................... 78 7. Curriculum Vitae ................................................................................................................................ 79 7. Scientific contributions ...................................................................................................................... 83 8. Acknowledgments ............................................................................................................................. 84 9. References ......................................................................................................................................... 85 3 Summary Ammonia is a ubiquitous metabolite in amino acid and protein metabolism. Despite its important roles in metabolism and pH homeostasis, ammonia needs to be rapidly and efficiently detoxified