Pharmaceutical Technology (Huwyler)Head of Research Unit Prof. Dr.Jörg Huwyler Prof. Dr.Hans LeuenbergerOverviewMembersPublicationsProjects & CollaborationsProjects & Collaborations OverviewMembersPublicationsProjects & Collaborations Projects & Collaborations 6 foundShow per page10 10 20 50 Development of novel synthetic gene transfer vectors for metabolic liver therapy Research Project | 2 Project MembersTherapeutic vectors for gene delivery remain the currently most challenging factor for human gene therapy. The translation from in vitro to in vivo applications remains a major hurdle for most nucleic acid delivery systems since there is an inherent lack of both efficient and safe carrier systems. For liver targeting of postmitotic hepatocytes, adeno-associated virus (AAV) derived vectors are thought to have the greatest potential despite concerns about a future routine clinical use. The major hurdles of AAV vectors for long-term treatment of pediatric patients are the risk of chromosomal integration and development of hepatocellular carcinoma, immune responses to viral vectors, limited loading capacity, and the difficulty to treat neonates which likely would require subsequent further injections. Consequently, the development of non-viral gene delivery systems has gained much attention due to their versatility, safety, and ease of manufacturing. During the last decades, a wide range of nanoparticle based gene delivery systems were developed and remarkable results in the field of RNA therapeutics were achieved. However, the induced pharmacological effects obtained by these siRNA or mRNA delivery strategies are short-lived and thus weekly administrations of therapeutic formulations are necessary. The use of DNA-based therapeutics would offer a favorable option for the induction of long-term therapeutic effects without need for insertion into the genome. Here, we propose an alternative approach to overcome the challenges of viral vectors or RNA-based therapeutics by developing novel nanoparticles for delivery of non-integrating, so-called minicircle (MC) vectors lacking any viral or bacterial components for liver-directed gene therapy. The successful use of MC vectors to treat genetic (metabolic) liver defects is based on the experience of one application partner with naked DNA-vectors delivered in an experimental setting by hydrodynamic pressure to either target pericentral or periportal hepatocytes to treat two classical defects in mouse models for human diseases, phenylketonuria (PKU) and ornithine transcarbamylase (OTC) deficiency, respectively. Such MC vectors exhibited persistent expression combined with basically no DNA size limitation, which made it possible to use natural promoters/enhancers in combination with introns to mimic "physiological" expression. While MC vectors bear almost ideal properties with great potential for liver gene therapy, delivery of naked DNA solely by hydrodynamic pressure is not applicable in a clinical setting. In an interdisciplinary approach, we want to develop multifunctional polymeric nanoparticles encapsulating MC vectors for non-viral gene delivery specifically to the key pathogenic cell type, i.e. hepatocytes. In order to optimize gene delivery efficiency, a novel library of polymer-peptide hybrids will be created, formulations strategies will be optimized and resulting nanoparticles will be validated in vivo using various animal models, i.e. transgenic mice, xenotransplanted mice with human liver or pig models. The combination of this novel class of polymer-peptide hybrids with a reproducible and scalable nanoparticle formulation technique (i.e. microfluidics) is expected to greatly impact further optimization of the synthetic gene delivery system for clinical applications. The overall aim of this translational project is the development of an alternative approach to AAV vectors with the potential of a breakthrough for liver gene therapy and thus a paradigm shift from potentially harmful viral vectors to safe, efficient and completely synthetic non-viral vectors. Drug Targeting to Hepatocytes: Gene Delivery using Myrcludex B Coupled Lipid Nanoparticles Research Project | 3 Project MembersHepatic disorders affect millions of people around the globe and incidence rates are further increasing. Current therapies for diseases of hepatocytes are limited and in most cases only treat symptoms. Therefore, improved therapeutic technologies are needed. Nanomedicines for the delivery of therapeutic genes have the potential to overcome the lack of satisfactory and alternative treatment options. This grant application focuses on the design of functional nanomedicines for targeted nucleic acid delivery (i.e. plasmid DNA) to liver parenchymal cells. The proposed project consists of three work-packages, which can be summarized as follows:First, specific and highly selective targeting of hepatocytes will be achieved using a targeting ligand derived from hepatitis B virus (HBV). This HBV entry inhibitor "Myrcludex B" consists of a lipid-conjugated polypeptide (i.e. the PreS1 domain of the large surface glycoprotein of HBV) and is characterized by a strong tropism for hepatocytes. Optimized Myrcludex B-derived lipopeptides will be conjugated to the surface of pegylated liposomes to mediate hepatocyte specific drug delivery. Second, in order to optimize loading and retention of DNA expression plasmids within lipid nanoparticles, a novel library of double tailed, ionizable amino-lipids will be created and screened for efficient and safe transfection activity. The combination of this new class of amino-lipids with a novel nanoparticle formulation technique (i.e. microfluidics) offers the possibility to optimize the transfection efficiency of the lipid-based delivery system. Third, in the final part of the project, both technologies will be combined to achieve targeted gene delivery to human hepatocytes; both in vitro in human liver derived cell lines as well as in vivo in different mouse models expressing the mouse or human NTCP, i.e. the entry point for HBV and at the same time our highly selective target structure on hepatocytes. With our novel targeting strategy, we have the possibility to address an unmet medical need. Non-viral gene delivery may offer well tolerated therapeutic options for diseases of the liver such as Crigler-Najjar syndrome, where a single gene defect leads to severe clinical manifestations. The proposed project will be the first step towards a future therapeutic intervention for this and other orphan liver diseases. Design of polymer nanoreactors with triggered activity Research Project | 2 Project MembersAn efficient way to overcome many of today's challenges in domains such as medicine, food science, catalysis, and environmental sciences is to design and use nanoreactors as protected reaction spaces for active compounds (enzymes, proteins, mimics) encapsulated/inserted in supramolecular polymer assemblies (micelles, spheres, vesicles) [1]. The overall aim of this PhD project is to develop triggered polymer nanoreactors by encapsulating/co-encapsulating enzymes and inserting channel proteins in polymer vesicles with sizes in the nanometer range. The triggered function is introduced by channel proteins that are modified so as to be open only in the presence of a specific chemical stimulus (protein gate). We will develop two types of nanoreactors intended to serve for: i. sensitive biosensing of pH changes, and ii. simultaneous detoxification of superoxide radicals and triggered production and release of compounds. The interactions of nanoreactors with biological systems will be tested with human liver carcinoma cell line HepG2 in terms of cellular binding, uptake and intracellular processing in order to support their further medical application [2] . [1] Palivan CG, Onaca O, Delcea M, Itel F, Meier W, Chem Soc. Rev. 2012 , 41(7), 2800 [2] Seeland S, Treiber A, Hafner M, Huwyler J, Biochim. Biophys. Acta , 2011 , 1808, 1827. Entwicklung mikropartikel-basierter Formulierungen zur gezielten Verabreichung pharmazeutischer Wirkstoffe Research Project | 1 Project MembersZusammenarbeit mit der Firma Tillotts Pharma AG auf dem Gebiet der pharmazeutischsen Technologie. COATED TABLETS CONSISTING OF A SUPER DISINTEGRANT CORE AND ITS EFFECT ON DRUG RELEASE Research Project | 2 Project MembersMicrocrystalline Cellulose (MCC), and its modifications, are well known and wide spread used excipients in the pharmaceutical industry. Cellulose II polymorph, which is obtained by mercerization from cellulose I polymorph (MCC), shows to behave as multifunctional excipient, working like filler as well as a super disintegrant. The objective of the present work was to investigate the possibility to create a modified drug release system based on rupturable coating applying to the cellulose II polymorph core, as well as to check the behavior of this core during an aqueous coating process. Three formulations containing cellulose II and proquazone, a poor water soluble drug, were produced. The amount of cellulose II in the mixtures was 10, 50 and 90% (w/w). Granules were produced using a lab scale high shear mixer and the power consumption was measured to monitor the process. After compression the tablet cores were coated in a bottom spray lab scale fluidized bed with Eudragit RS ® 30D, Eudragit RL ® 30D and Aquacoat ECD ® 30%. Subsequently, the drug release profile was analyzed using USP paddle method. The results showed that an aqueous coating process is possible using a core with a high load of a super disintegrant if the proper parameters are set, regarding the inlet temperature, atomizing air and spray rate. The drug release showed to be dependent on the polymer type, the thickness of the coating layer and core composition. A sustained drug release with no lag time was obtained using different mixtures of Eudragit ® polymers. A delayed drug release, with a sigmoidal curve, and presenting different lag times according to the coating thickness, was obtained with Aquacoat. With thinner coating layers the lag time showed to be similar between the tablets containing 50 and 90% of cellulose II, showing the influence of this excipient in the core by swelling and coating disruption. These findings reveal a good opportunity to develop a modified drug delivery system based on approved and well known excipients and also applying conventional processes. Pharmaceutical process optimization of disordered particulate systems using Computer Aided Design (CAD) and Artificial Neural Networks (ANN) Research Project | 2 Project MembersTablets are complex systems and the behaviour of disordered particulates under pressure is still far from being well understood, especially with high-speed compression cycles similar to presses used in industry. Manufacturing problems are usually discovered towards the end of the development process when high speed compression runs are studied for the first time. The use of a compaction simulator in the early stage of development is a significant benefit for the product development process. Since tablets are particulate materials, their physical aspects have much in common with the problems, which are studied by other engineering sciences and reflect the interdisciplinary character of the research field. In the pharmaceutical process of tablet production, wet granulation is commonly applied to powder mixtures in order to improve powder characteristics, such as flow and compressibility. The desired granulate properties are controlled by a combination of formulation design (choosing the starting material and liquid according to its properties) and process design (choosing the type of granulator and the operating parameters). Changing the formulation and/or the process is followed by a high number of experiments based on the "trial and error principle". The compaction simulator allows simulating mechanically a multi station rotary tablet press, on the basis of the dwell time, of the material to be compressed. A tablet formulation is usually developed using slow (large dwell time) single station tablet presses and is afterwards transferred to a high speed tableting machine with a small dwell time of the material to be compressed. In fact, up to now scale-up of the tableting process is still an empirical process. Furthermore, the tablet presses are running with increasing capacities (e.g., one million tablets per hour) and not every tablet formulation is capable for high speed tabletting. The key is to search for mathematical models, which are able to predict the performance of a tablet formulation. Special focus will be spent on excipients exhibiting different polymorphic modifications and recently obtained results confirm the importance of particle shape and surface of the particulate system during tablet formation. Many problems are discovered during high-speed tableting, such as adhesion and insufficient tablet strength due to the decreasing dwell time. These critical steps will be analyzed and the formulations will be optimized by the application of percolation theory. Further research work is aimed to follow this direction. 1 1 OverviewMembersPublicationsProjects & Collaborations
Projects & Collaborations 6 foundShow per page10 10 20 50 Development of novel synthetic gene transfer vectors for metabolic liver therapy Research Project | 2 Project MembersTherapeutic vectors for gene delivery remain the currently most challenging factor for human gene therapy. The translation from in vitro to in vivo applications remains a major hurdle for most nucleic acid delivery systems since there is an inherent lack of both efficient and safe carrier systems. For liver targeting of postmitotic hepatocytes, adeno-associated virus (AAV) derived vectors are thought to have the greatest potential despite concerns about a future routine clinical use. The major hurdles of AAV vectors for long-term treatment of pediatric patients are the risk of chromosomal integration and development of hepatocellular carcinoma, immune responses to viral vectors, limited loading capacity, and the difficulty to treat neonates which likely would require subsequent further injections. Consequently, the development of non-viral gene delivery systems has gained much attention due to their versatility, safety, and ease of manufacturing. During the last decades, a wide range of nanoparticle based gene delivery systems were developed and remarkable results in the field of RNA therapeutics were achieved. However, the induced pharmacological effects obtained by these siRNA or mRNA delivery strategies are short-lived and thus weekly administrations of therapeutic formulations are necessary. The use of DNA-based therapeutics would offer a favorable option for the induction of long-term therapeutic effects without need for insertion into the genome. Here, we propose an alternative approach to overcome the challenges of viral vectors or RNA-based therapeutics by developing novel nanoparticles for delivery of non-integrating, so-called minicircle (MC) vectors lacking any viral or bacterial components for liver-directed gene therapy. The successful use of MC vectors to treat genetic (metabolic) liver defects is based on the experience of one application partner with naked DNA-vectors delivered in an experimental setting by hydrodynamic pressure to either target pericentral or periportal hepatocytes to treat two classical defects in mouse models for human diseases, phenylketonuria (PKU) and ornithine transcarbamylase (OTC) deficiency, respectively. Such MC vectors exhibited persistent expression combined with basically no DNA size limitation, which made it possible to use natural promoters/enhancers in combination with introns to mimic "physiological" expression. While MC vectors bear almost ideal properties with great potential for liver gene therapy, delivery of naked DNA solely by hydrodynamic pressure is not applicable in a clinical setting. In an interdisciplinary approach, we want to develop multifunctional polymeric nanoparticles encapsulating MC vectors for non-viral gene delivery specifically to the key pathogenic cell type, i.e. hepatocytes. In order to optimize gene delivery efficiency, a novel library of polymer-peptide hybrids will be created, formulations strategies will be optimized and resulting nanoparticles will be validated in vivo using various animal models, i.e. transgenic mice, xenotransplanted mice with human liver or pig models. The combination of this novel class of polymer-peptide hybrids with a reproducible and scalable nanoparticle formulation technique (i.e. microfluidics) is expected to greatly impact further optimization of the synthetic gene delivery system for clinical applications. The overall aim of this translational project is the development of an alternative approach to AAV vectors with the potential of a breakthrough for liver gene therapy and thus a paradigm shift from potentially harmful viral vectors to safe, efficient and completely synthetic non-viral vectors. Drug Targeting to Hepatocytes: Gene Delivery using Myrcludex B Coupled Lipid Nanoparticles Research Project | 3 Project MembersHepatic disorders affect millions of people around the globe and incidence rates are further increasing. Current therapies for diseases of hepatocytes are limited and in most cases only treat symptoms. Therefore, improved therapeutic technologies are needed. Nanomedicines for the delivery of therapeutic genes have the potential to overcome the lack of satisfactory and alternative treatment options. This grant application focuses on the design of functional nanomedicines for targeted nucleic acid delivery (i.e. plasmid DNA) to liver parenchymal cells. The proposed project consists of three work-packages, which can be summarized as follows:First, specific and highly selective targeting of hepatocytes will be achieved using a targeting ligand derived from hepatitis B virus (HBV). This HBV entry inhibitor "Myrcludex B" consists of a lipid-conjugated polypeptide (i.e. the PreS1 domain of the large surface glycoprotein of HBV) and is characterized by a strong tropism for hepatocytes. Optimized Myrcludex B-derived lipopeptides will be conjugated to the surface of pegylated liposomes to mediate hepatocyte specific drug delivery. Second, in order to optimize loading and retention of DNA expression plasmids within lipid nanoparticles, a novel library of double tailed, ionizable amino-lipids will be created and screened for efficient and safe transfection activity. The combination of this new class of amino-lipids with a novel nanoparticle formulation technique (i.e. microfluidics) offers the possibility to optimize the transfection efficiency of the lipid-based delivery system. Third, in the final part of the project, both technologies will be combined to achieve targeted gene delivery to human hepatocytes; both in vitro in human liver derived cell lines as well as in vivo in different mouse models expressing the mouse or human NTCP, i.e. the entry point for HBV and at the same time our highly selective target structure on hepatocytes. With our novel targeting strategy, we have the possibility to address an unmet medical need. Non-viral gene delivery may offer well tolerated therapeutic options for diseases of the liver such as Crigler-Najjar syndrome, where a single gene defect leads to severe clinical manifestations. The proposed project will be the first step towards a future therapeutic intervention for this and other orphan liver diseases. Design of polymer nanoreactors with triggered activity Research Project | 2 Project MembersAn efficient way to overcome many of today's challenges in domains such as medicine, food science, catalysis, and environmental sciences is to design and use nanoreactors as protected reaction spaces for active compounds (enzymes, proteins, mimics) encapsulated/inserted in supramolecular polymer assemblies (micelles, spheres, vesicles) [1]. The overall aim of this PhD project is to develop triggered polymer nanoreactors by encapsulating/co-encapsulating enzymes and inserting channel proteins in polymer vesicles with sizes in the nanometer range. The triggered function is introduced by channel proteins that are modified so as to be open only in the presence of a specific chemical stimulus (protein gate). We will develop two types of nanoreactors intended to serve for: i. sensitive biosensing of pH changes, and ii. simultaneous detoxification of superoxide radicals and triggered production and release of compounds. The interactions of nanoreactors with biological systems will be tested with human liver carcinoma cell line HepG2 in terms of cellular binding, uptake and intracellular processing in order to support their further medical application [2] . [1] Palivan CG, Onaca O, Delcea M, Itel F, Meier W, Chem Soc. Rev. 2012 , 41(7), 2800 [2] Seeland S, Treiber A, Hafner M, Huwyler J, Biochim. Biophys. Acta , 2011 , 1808, 1827. Entwicklung mikropartikel-basierter Formulierungen zur gezielten Verabreichung pharmazeutischer Wirkstoffe Research Project | 1 Project MembersZusammenarbeit mit der Firma Tillotts Pharma AG auf dem Gebiet der pharmazeutischsen Technologie. COATED TABLETS CONSISTING OF A SUPER DISINTEGRANT CORE AND ITS EFFECT ON DRUG RELEASE Research Project | 2 Project MembersMicrocrystalline Cellulose (MCC), and its modifications, are well known and wide spread used excipients in the pharmaceutical industry. Cellulose II polymorph, which is obtained by mercerization from cellulose I polymorph (MCC), shows to behave as multifunctional excipient, working like filler as well as a super disintegrant. The objective of the present work was to investigate the possibility to create a modified drug release system based on rupturable coating applying to the cellulose II polymorph core, as well as to check the behavior of this core during an aqueous coating process. Three formulations containing cellulose II and proquazone, a poor water soluble drug, were produced. The amount of cellulose II in the mixtures was 10, 50 and 90% (w/w). Granules were produced using a lab scale high shear mixer and the power consumption was measured to monitor the process. After compression the tablet cores were coated in a bottom spray lab scale fluidized bed with Eudragit RS ® 30D, Eudragit RL ® 30D and Aquacoat ECD ® 30%. Subsequently, the drug release profile was analyzed using USP paddle method. The results showed that an aqueous coating process is possible using a core with a high load of a super disintegrant if the proper parameters are set, regarding the inlet temperature, atomizing air and spray rate. The drug release showed to be dependent on the polymer type, the thickness of the coating layer and core composition. A sustained drug release with no lag time was obtained using different mixtures of Eudragit ® polymers. A delayed drug release, with a sigmoidal curve, and presenting different lag times according to the coating thickness, was obtained with Aquacoat. With thinner coating layers the lag time showed to be similar between the tablets containing 50 and 90% of cellulose II, showing the influence of this excipient in the core by swelling and coating disruption. These findings reveal a good opportunity to develop a modified drug delivery system based on approved and well known excipients and also applying conventional processes. Pharmaceutical process optimization of disordered particulate systems using Computer Aided Design (CAD) and Artificial Neural Networks (ANN) Research Project | 2 Project MembersTablets are complex systems and the behaviour of disordered particulates under pressure is still far from being well understood, especially with high-speed compression cycles similar to presses used in industry. Manufacturing problems are usually discovered towards the end of the development process when high speed compression runs are studied for the first time. The use of a compaction simulator in the early stage of development is a significant benefit for the product development process. Since tablets are particulate materials, their physical aspects have much in common with the problems, which are studied by other engineering sciences and reflect the interdisciplinary character of the research field. In the pharmaceutical process of tablet production, wet granulation is commonly applied to powder mixtures in order to improve powder characteristics, such as flow and compressibility. The desired granulate properties are controlled by a combination of formulation design (choosing the starting material and liquid according to its properties) and process design (choosing the type of granulator and the operating parameters). Changing the formulation and/or the process is followed by a high number of experiments based on the "trial and error principle". The compaction simulator allows simulating mechanically a multi station rotary tablet press, on the basis of the dwell time, of the material to be compressed. A tablet formulation is usually developed using slow (large dwell time) single station tablet presses and is afterwards transferred to a high speed tableting machine with a small dwell time of the material to be compressed. In fact, up to now scale-up of the tableting process is still an empirical process. Furthermore, the tablet presses are running with increasing capacities (e.g., one million tablets per hour) and not every tablet formulation is capable for high speed tabletting. The key is to search for mathematical models, which are able to predict the performance of a tablet formulation. Special focus will be spent on excipients exhibiting different polymorphic modifications and recently obtained results confirm the importance of particle shape and surface of the particulate system during tablet formation. Many problems are discovered during high-speed tableting, such as adhesion and insufficient tablet strength due to the decreasing dwell time. These critical steps will be analyzed and the formulations will be optimized by the application of percolation theory. Further research work is aimed to follow this direction. 1 1
Development of novel synthetic gene transfer vectors for metabolic liver therapy Research Project | 2 Project MembersTherapeutic vectors for gene delivery remain the currently most challenging factor for human gene therapy. The translation from in vitro to in vivo applications remains a major hurdle for most nucleic acid delivery systems since there is an inherent lack of both efficient and safe carrier systems. For liver targeting of postmitotic hepatocytes, adeno-associated virus (AAV) derived vectors are thought to have the greatest potential despite concerns about a future routine clinical use. The major hurdles of AAV vectors for long-term treatment of pediatric patients are the risk of chromosomal integration and development of hepatocellular carcinoma, immune responses to viral vectors, limited loading capacity, and the difficulty to treat neonates which likely would require subsequent further injections. Consequently, the development of non-viral gene delivery systems has gained much attention due to their versatility, safety, and ease of manufacturing. During the last decades, a wide range of nanoparticle based gene delivery systems were developed and remarkable results in the field of RNA therapeutics were achieved. However, the induced pharmacological effects obtained by these siRNA or mRNA delivery strategies are short-lived and thus weekly administrations of therapeutic formulations are necessary. The use of DNA-based therapeutics would offer a favorable option for the induction of long-term therapeutic effects without need for insertion into the genome. Here, we propose an alternative approach to overcome the challenges of viral vectors or RNA-based therapeutics by developing novel nanoparticles for delivery of non-integrating, so-called minicircle (MC) vectors lacking any viral or bacterial components for liver-directed gene therapy. The successful use of MC vectors to treat genetic (metabolic) liver defects is based on the experience of one application partner with naked DNA-vectors delivered in an experimental setting by hydrodynamic pressure to either target pericentral or periportal hepatocytes to treat two classical defects in mouse models for human diseases, phenylketonuria (PKU) and ornithine transcarbamylase (OTC) deficiency, respectively. Such MC vectors exhibited persistent expression combined with basically no DNA size limitation, which made it possible to use natural promoters/enhancers in combination with introns to mimic "physiological" expression. While MC vectors bear almost ideal properties with great potential for liver gene therapy, delivery of naked DNA solely by hydrodynamic pressure is not applicable in a clinical setting. In an interdisciplinary approach, we want to develop multifunctional polymeric nanoparticles encapsulating MC vectors for non-viral gene delivery specifically to the key pathogenic cell type, i.e. hepatocytes. In order to optimize gene delivery efficiency, a novel library of polymer-peptide hybrids will be created, formulations strategies will be optimized and resulting nanoparticles will be validated in vivo using various animal models, i.e. transgenic mice, xenotransplanted mice with human liver or pig models. The combination of this novel class of polymer-peptide hybrids with a reproducible and scalable nanoparticle formulation technique (i.e. microfluidics) is expected to greatly impact further optimization of the synthetic gene delivery system for clinical applications. The overall aim of this translational project is the development of an alternative approach to AAV vectors with the potential of a breakthrough for liver gene therapy and thus a paradigm shift from potentially harmful viral vectors to safe, efficient and completely synthetic non-viral vectors.
Drug Targeting to Hepatocytes: Gene Delivery using Myrcludex B Coupled Lipid Nanoparticles Research Project | 3 Project MembersHepatic disorders affect millions of people around the globe and incidence rates are further increasing. Current therapies for diseases of hepatocytes are limited and in most cases only treat symptoms. Therefore, improved therapeutic technologies are needed. Nanomedicines for the delivery of therapeutic genes have the potential to overcome the lack of satisfactory and alternative treatment options. This grant application focuses on the design of functional nanomedicines for targeted nucleic acid delivery (i.e. plasmid DNA) to liver parenchymal cells. The proposed project consists of three work-packages, which can be summarized as follows:First, specific and highly selective targeting of hepatocytes will be achieved using a targeting ligand derived from hepatitis B virus (HBV). This HBV entry inhibitor "Myrcludex B" consists of a lipid-conjugated polypeptide (i.e. the PreS1 domain of the large surface glycoprotein of HBV) and is characterized by a strong tropism for hepatocytes. Optimized Myrcludex B-derived lipopeptides will be conjugated to the surface of pegylated liposomes to mediate hepatocyte specific drug delivery. Second, in order to optimize loading and retention of DNA expression plasmids within lipid nanoparticles, a novel library of double tailed, ionizable amino-lipids will be created and screened for efficient and safe transfection activity. The combination of this new class of amino-lipids with a novel nanoparticle formulation technique (i.e. microfluidics) offers the possibility to optimize the transfection efficiency of the lipid-based delivery system. Third, in the final part of the project, both technologies will be combined to achieve targeted gene delivery to human hepatocytes; both in vitro in human liver derived cell lines as well as in vivo in different mouse models expressing the mouse or human NTCP, i.e. the entry point for HBV and at the same time our highly selective target structure on hepatocytes. With our novel targeting strategy, we have the possibility to address an unmet medical need. Non-viral gene delivery may offer well tolerated therapeutic options for diseases of the liver such as Crigler-Najjar syndrome, where a single gene defect leads to severe clinical manifestations. The proposed project will be the first step towards a future therapeutic intervention for this and other orphan liver diseases.
Design of polymer nanoreactors with triggered activity Research Project | 2 Project MembersAn efficient way to overcome many of today's challenges in domains such as medicine, food science, catalysis, and environmental sciences is to design and use nanoreactors as protected reaction spaces for active compounds (enzymes, proteins, mimics) encapsulated/inserted in supramolecular polymer assemblies (micelles, spheres, vesicles) [1]. The overall aim of this PhD project is to develop triggered polymer nanoreactors by encapsulating/co-encapsulating enzymes and inserting channel proteins in polymer vesicles with sizes in the nanometer range. The triggered function is introduced by channel proteins that are modified so as to be open only in the presence of a specific chemical stimulus (protein gate). We will develop two types of nanoreactors intended to serve for: i. sensitive biosensing of pH changes, and ii. simultaneous detoxification of superoxide radicals and triggered production and release of compounds. The interactions of nanoreactors with biological systems will be tested with human liver carcinoma cell line HepG2 in terms of cellular binding, uptake and intracellular processing in order to support their further medical application [2] . [1] Palivan CG, Onaca O, Delcea M, Itel F, Meier W, Chem Soc. Rev. 2012 , 41(7), 2800 [2] Seeland S, Treiber A, Hafner M, Huwyler J, Biochim. Biophys. Acta , 2011 , 1808, 1827.
Entwicklung mikropartikel-basierter Formulierungen zur gezielten Verabreichung pharmazeutischer Wirkstoffe Research Project | 1 Project MembersZusammenarbeit mit der Firma Tillotts Pharma AG auf dem Gebiet der pharmazeutischsen Technologie.
COATED TABLETS CONSISTING OF A SUPER DISINTEGRANT CORE AND ITS EFFECT ON DRUG RELEASE Research Project | 2 Project MembersMicrocrystalline Cellulose (MCC), and its modifications, are well known and wide spread used excipients in the pharmaceutical industry. Cellulose II polymorph, which is obtained by mercerization from cellulose I polymorph (MCC), shows to behave as multifunctional excipient, working like filler as well as a super disintegrant. The objective of the present work was to investigate the possibility to create a modified drug release system based on rupturable coating applying to the cellulose II polymorph core, as well as to check the behavior of this core during an aqueous coating process. Three formulations containing cellulose II and proquazone, a poor water soluble drug, were produced. The amount of cellulose II in the mixtures was 10, 50 and 90% (w/w). Granules were produced using a lab scale high shear mixer and the power consumption was measured to monitor the process. After compression the tablet cores were coated in a bottom spray lab scale fluidized bed with Eudragit RS ® 30D, Eudragit RL ® 30D and Aquacoat ECD ® 30%. Subsequently, the drug release profile was analyzed using USP paddle method. The results showed that an aqueous coating process is possible using a core with a high load of a super disintegrant if the proper parameters are set, regarding the inlet temperature, atomizing air and spray rate. The drug release showed to be dependent on the polymer type, the thickness of the coating layer and core composition. A sustained drug release with no lag time was obtained using different mixtures of Eudragit ® polymers. A delayed drug release, with a sigmoidal curve, and presenting different lag times according to the coating thickness, was obtained with Aquacoat. With thinner coating layers the lag time showed to be similar between the tablets containing 50 and 90% of cellulose II, showing the influence of this excipient in the core by swelling and coating disruption. These findings reveal a good opportunity to develop a modified drug delivery system based on approved and well known excipients and also applying conventional processes.
Pharmaceutical process optimization of disordered particulate systems using Computer Aided Design (CAD) and Artificial Neural Networks (ANN) Research Project | 2 Project MembersTablets are complex systems and the behaviour of disordered particulates under pressure is still far from being well understood, especially with high-speed compression cycles similar to presses used in industry. Manufacturing problems are usually discovered towards the end of the development process when high speed compression runs are studied for the first time. The use of a compaction simulator in the early stage of development is a significant benefit for the product development process. Since tablets are particulate materials, their physical aspects have much in common with the problems, which are studied by other engineering sciences and reflect the interdisciplinary character of the research field. In the pharmaceutical process of tablet production, wet granulation is commonly applied to powder mixtures in order to improve powder characteristics, such as flow and compressibility. The desired granulate properties are controlled by a combination of formulation design (choosing the starting material and liquid according to its properties) and process design (choosing the type of granulator and the operating parameters). Changing the formulation and/or the process is followed by a high number of experiments based on the "trial and error principle". The compaction simulator allows simulating mechanically a multi station rotary tablet press, on the basis of the dwell time, of the material to be compressed. A tablet formulation is usually developed using slow (large dwell time) single station tablet presses and is afterwards transferred to a high speed tableting machine with a small dwell time of the material to be compressed. In fact, up to now scale-up of the tableting process is still an empirical process. Furthermore, the tablet presses are running with increasing capacities (e.g., one million tablets per hour) and not every tablet formulation is capable for high speed tabletting. The key is to search for mathematical models, which are able to predict the performance of a tablet formulation. Special focus will be spent on excipients exhibiting different polymorphic modifications and recently obtained results confirm the importance of particle shape and surface of the particulate system during tablet formation. Many problems are discovered during high-speed tableting, such as adhesion and insufficient tablet strength due to the decreasing dwell time. These critical steps will be analyzed and the formulations will be optimized by the application of percolation theory. Further research work is aimed to follow this direction.
