Development of hot-melt extrusion as a novel technique for the formulation of oral solid dosage forms

Hot-melt extrusion (HME) is one of the most widely used technologies in the plastic, rubber and food industries and it has also been extensively explored and used in academia and the pharmaceutical industry over the last decade. This project aims to investigate the efficiency of hydrophilic polymers to enhance the dissolution rate of poorly water-soluble APIs processed by HME. Indomethacin (INM) and famotidine (FMT) were selected as model active substances while polyvinyl caprolactam graft copolymer, Soluplus® (SOL) and vinylpyrrolidone-vinyl acetate copolymer grades Kollidon® VA64 (VA64) and Plasdone® S630 (S630) were used as hydrophilic polymeric carriers. For the purpose of the study, all drug-polymer binary blends at various ratios were processed by a Randcastle single screw extruder. The physico-chemical properties and the morphology of the extrudates were evaluated via x-ray powder diffraction (XRPD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). INM and FMT exhibited strong plasticization effects at specific concentrations and were found to be molecularly dispersed within the polymer blends. The in vitro dissolution studies showed increased INM/FMT release rates for all formulations compared to that of pure APIs alone. Ibuprofen was also embedded in a methacrylate copolymer (Eudragit® EPO) matrix to produce solid dispersions by hot-melt extrusion processing. The obtained granules were incorporated into orally disintegrating tablets (ODTs). The tablets were developed by varying the ratio of superdisintegrants such as sodium croscarmellose and cross-linked polyvinylpyrrolidone while a direct compression process was used to compress the ODTs under various compaction forces to optimize tablet robustness. The properties of the compressed tablets which included porosity, hardness, and friability and dissolution profiles were further evaluated and compared with commercially available Nurofen® Meltlet ODTs. In vitro dissolution of the extruded ODTs showed rapid release of ibuprofen compared to that of Nurofen® Meltlets. The in vitro and in vivo evaluation of the masking efficiency of hot melt extruded paracetamol (PMOL) formulations was examined. Extruded granules containing high PMOL loadings in Eudragit EPO® (EPO) or Kollidon® VA64 (VA64) were prepared by HME. Similarly propranolol HCl (PRP), diphenhydramine HCl (DPD), cetirizine HCl (CTZ) and verapamil HCl (VRP) were used as model cationic active substances while pH sensitive anionic methacrylic acid based methyl methacrylate coplolymers Eudragit® L100 (L100) and ethyl acrylate copolymer Eudragit® L100-55 (Acryl-EZE®) (L100-55) were used as polymeric carriers in order to produce taste masked extruded formulations determining drug-polymers intermolecular interactions. The taste masking effect of the processed formulation was evaluated in vivo by a panel of six healthy human volunteers. In addition, in vitro evaluation was carried out by an Astree e-tongue (Alpha MOS) equipped with seven sensors and Taste Sensing System TS5000Z (INSENT), respectively. The taste and sensory evaluation in human volunteers demonstrated that the formulation masked the bitter taste of the APIs and improved tablet palatability. In addition to that the taste sensing technology demonstrated taste improvement for all polymers by correlating the data obtained for the placebo polymers and the pure APIs alone. The e-tongue results were in good agreement with the in vivo evaluation. Molecular modelling (Gaussian 09) predicted the existence of two possible H-bonding types while Fourier Transform Infra-Red (FT-IR) and NMR studies confirmed drug-polymer interactions between the functional groups of both components (cationic drugs–anionic polymers). Furthermore, the intermolecular interactions evaluated by Flory-Huggins interaction parameters theory and X-ray photoelectron spectroscopy (XPS) showed stronger interactions between drug-polymer in L100 systems compared to that of L100-55 systems. The mechanism of the intermolecular interactions derived from this research showed the presence of H bonding between the amine group of the active substances and the carboxylic groups in the polymer. Hydrocortisone (HCS) was also embedded and extruded with ethyl cellulose N10 (EC N10) or ethyl cellulose Premium 7 (EC P7) in order to develop sustained release tablets processed by HME. The compressed tablets were subsequently coated with an enteric coating polymer, Eudragit® S100 (15-20%), which showed sustained release over 12 hrs with a lag time of 2 hrs. Further analysis of the release mechanism of HCS from tablets was performed by implementing five different kinetic release models which confirmed that the release of HCS from both coated and uncoated tablets followed a first order kinetic model

Development of Multivariate Powder X-ray Diffraction Techniques and Total Scattering Analyses to Enable Informatic Calibration of Solid Dispersion Potential

The objective of this work was to introduce a novel method for predicting solid dispersion potential enabled by the ability to differentiate phase-separated co-solidified products from amorphous molecular solid dispersions. The central hypothesis states that a combination of materials properties exists that defines the propensity of an active pharmaceutical ingredient to form a binary amorphous molecular solid dispersion with polyvinylpyrrolidone:vinyl acetate copolymer using a melt-quench procedure. Testing this hypothesis required execution of specific aims directed to address issues inherent to characterizing amorphous materials. The work herein is presented with respect to two separate subjects: (1) analytical development and (2) theoretical applications. In the first few chapters, advanced powder X-ray diffraction data processing techniques are explored and adapted to composite pharmaceutical systems. Specific emphasis will be placed ontotal scattering data manipulations and their benefits over traditional practices. The concluding part of this work is devoted to illustrating the use of materials informatics in modeling solid dispersion potential, ultimately afforded by implementing the materials characterization methodologies developed in the initial stages. Molecular descriptors, commonly employed in quantitative structure-property relationship assessment, were tested for correlation to dispersion potential across a library of small molecule organic compounds. The final model accurately predicted dispersion potential for all 12 calibration compounds and three test compounds

Solubility Enhancement via Melt Extrusion: Drug-polymer Solubility, Physicochemical Characterization and Quality by Design

Many new drugs developed face oral delivery challenges and absorption due to poor biopharmaceutical properties. Formation of solid dispersions is a very widely applied technique for solubility enhancement of water insoluble drugs. In order to form stable solid dispersions it is important to select appropriate excipients that will maintain the drug in its amorphous form for an extended period of time. Selection of appropriate excipients is critical during the development of stable amorphous solid dispersions. The solubility parameter concept has been explored for theoretically identifying the excipients that will be suitable based on the structure of the active. In this work, the use of solubility parameter has been explored for strategic selection of excipients for a model drug ibuprofen. The predicted miscibility limits are verified with experimentally determined solubility limits. Dissolution experiments have been conducted to demonstrate the advantage of amorphous solid dispersions. This has been further extended by in depth thermal and chemical characterization of the ibuprofen and Eudragit® E PO system. A phase diagram is predicted based on the understanding of the relationship between temperature, ratio of ibuprofen and the Gibbs free energy. Room temperature miscibility of the two components is demonstrated using microscopic studies. The potential of ionic interactions is investigated using spectroscopic techniques. Melt extruded formulations are evaluated for the physical state of ibuprofen and stability of the amorphous form. A complete Quality by Design study was performed for preparation of ibuprofen-Eudragit® E PO extrudates. Risk assessment was performed using the fishbone diagram and Failure Mode Effect Analysis and the factors influencing this melt extrusion process were shortlisted and prioritized. The most critical factors were then assessed in a 30 run experimental design. Torque, Glass Transition temperature, Assay and Dissolution at 30 min were measured as responses and the results were statistically analyzed to predict a design space. Finally, mechanistic evaluation of Ketoconazole and Kollidon® VA 64 solid dispersions was performed using thermal techniques, dissolution, swelling and erosion studied

Evaluation of the safety and pharmacokinetic profile of the broad spectrum antiviral lectin Griffithsin.

Carbohydrate binding agents that target viral envelope glycans are being studied for their potential use as microbicides and antiviral therapeutics. Griffithsin is a lectin originally identified in a red alga Griffithisia sp. Multiple studies have shown that GRFT inhibits HIV-1, Coronaviruses, Hepatitis C, influenza and Ebola virus replication in vitro. This antiviral activity suggests potential uses in chemoprophylaxis and disease treatment. However, safety of GRFT administration has not been extensively studied. In vivo testing--chronic subcutaneous treatment as well as single dose subcutaneous, oral, and intravenous administrations of Griffithsin in Sprague Dawley Rats (Rattus Norvegicus)--was used to assess Griffithsin’s pharmacokinetic properties and to predict whether use of Griffithsin for antiviral treatment might be safe and effective. Based on histological, serological, and biochemical data derived from these experiments, Griffithsin is generally well tolerated. However, protein binding assays revealed interactions with complement and apolipoproteins and calorimetric assays revealed changes in serum thermograms that may require further study

New Applications of Hot Melt Extrusion Techniques for Advancing Oral Drug Delivery

Hot melt extrusion (HME) is a promising technology in the pharmaceutical field, as evidenced by its application in the development of various formulations such as abuse deterrent (AD), amorphous solid dispersions (ASDs), cocrystals etc.The extended-release (ER) HME pellets of acetaminophen, a model drug, by utilizing high molecular weight polyethylene oxide (PEO) and gelling agents (xanthan gum, guar gum, and gellan gum) were prepared using HME to provide abuse-deterrent properties. The PEO/xanthan gum-based formulation showed higher viscosity, syringe and injection forces, and lower syringeable volume in all manipulation conditions compared to the other formulations, suggesting the AD potential of PEO and xanthan gum pellets against intravenous abuse. The impact of peroxides in Plasdone™ S630 Ultra and Plasdone™ S630 on the oxidative degradation of quetiapine fumarate hot melt extruded ASDs were investigated. The N-oxide impurity levels in the quetiapine fumarate - Plasdone™ S630 Ultra milled extrudates and tablet formulations were reduced by 2- and 3-folds, respectively, compared to those in quetiapine fumarate - Plasdone™ S630. The reduced oxidative degradation and improved HME processability of Plasdone™ S630 Ultra make it a better choice for oxidation-labile drugs over Plasdone™ S630 copovidone. The impact of binary and ternary ASDs on the supersaturation kinetics of NIF using the polymers hydroxypropylmethylcellulose acetate succinate (HPMCAS) LG, and HG, Eudragit® RSPO, Eudragit® FS100, Kollidon® VA64 and Plasdone™ K-29/32 was investigated to maintain nifedipine supersaturation over a prolonged period. A synergistic effect emerged for ternary NIF/HPMCAS-LG/HPMCAS-HG, and NIF/HPMCAS-LG/Eudragit®FS100 systems maintained the supersaturation level with enhanced dissolution performance, demonstrating the potential of polymeric combinations for improved ASD performance. The pharmaceutical cocrystals were prepared by a solvent-free HME to improve the solubility and dissolution rate. Aripiprazole (ARP) and adipic acid (ADP) were used as a drug and coformer, respectively. Incorporating 5% SOL into the ARP-ADP blend reduced the processing torque and improved processability. FTIR spectra revealed non-covalent interaction between ARP and ADP. The PXRD data exhibited characteristic peaks confirming the formation of new crystalline material with higher dissolution rates compared to the pure ARP, suggesting the suitability of cocrystals in the development of solid dosage forms

Pharmaceutical Co-crystals; Screening Optimisation, Utility and Performance

Co-crystallisation is currently a ‘hot topic’ in pharmaceutical development among other fields. Modification of the physicochemical properties of the parent material by inclusion of a second component within the crystal structure, with the potential to lead to large improvements in useful attributes, being the key reason for the interest in co-crystals. Being able to efficiently utilise co-crystallisation to ameliorate problem properties of drugs or other compounds would be a boon to many industries, the pharmaceutical being an ideal example. Limitations in current ability to predict co-crystal formation and potential property modification presents a great opportunity for development in this research area. The work presented in this thesis encompasses the optimisation of a high-throughput ultrasonication based physical co-crystal screen paired with a computational pre-screen, the application of this optimised screen and the analysis of both co-crystalline and co-amorphous materials resulting from the screening. An initial optimisation of a manual physical co-crystal screen was later transferred to an automated screen implemented on a robotics platform. The implementation of the screen and subsequent analysis of products led to the discovery of the stabilisation of an amorphous form of highly polymorphic compound, ROY, through a predicted co-former interaction. The interactions responsible for the stabilisation were further investigated in the ROY:pyrogallol co-amorphous material and it was found that certain analogues of pyrogallol exhibit the same behaviour with ROY depending on the presence and position of specific functionality. Implementation of the optimised co-crystal screen to the antiprotozoal drug ornidazole led to the detection of 23 hits and the crystal structure of the 1:1 co-crystal of ornidazole and 5nitroisophthalic acid being determined by single crystal X-ray diffraction. Characterisation of this co-crystal found that it crystallised much more readily than pure ornidazole, potentially improving its processing characteristics, but that unexpectedly had a lower intrinsic dissolution rate than either of the parent components. In comparison, formulation and characterisation of the already known zafirlukast:piperazine co-crystals showed that large improvements in dissolution rates and oral bioavailability in relation to the parent drug are possible. Specifically, the 1:1 zafirlukast:piperazine co-crystal showed a large increase in dissolution rate in vitro and an accompanying six-fold increase in in vivo oral bioavailability

Characterization of starch amorphous solid dispersions manufactured via hot-melt extrusion by calorimetry and diffractometry

Trabalho Final de Mestrado Integrado, Ciências Farmacêuticas, 2020, Universidade de Lisboa, Faculdade de Farmácia.Uma tarefa desafiadora para a indústria farmacêutica tem sido a melhoria da solubilidade de fármacos pouco solúveis em água. A produção de dispersões sólidas amorfas constitui uma das estratégias mais promissoras para aumentar a solubilidade, velocidade de libertação e biodisponibilidade destes fármacos. Este estudo propõe a produção de dispersões sólidas amorfas com fármacos de classe II do Sistema de Classificação Biofarmacêutica, através da extrusão a quente, tecnologia que permite o aumento da solubilidade em água, usando um polímero natural e biodegradável, o amido. Os fármacos em estudo, Ibuprofeno e Carbamazepina, classificados como fármacos de classe II (baixa solubilidade e elevada permeabilidade), foram formulados com amido de milho e amido de milho glutinoso. O amido é constituído por dois biopolímeros, amilose, uma macromolécula linear, e amilopectina, uma macromolécula altamente ramificada. O Ibuprofeno e a água foram usados pelos seus efeitos plastificantes. Primeiro, a mistura das formulações foi feita num misturador de tambor. A calorimetria diferencial de varrimento foi usada para determinar a temperatura de transição vítrea dos amidos. Durante a extrusão, a água foi adicionada ao extrusor de duplo parafuso co-rotativo através de uma bomba. Depois, as amostras foram secadas em estufa a 40°C durante ±12h e a moagem foi feita em almofariz e num moinho de bolas. Apresenta-se uma visão geral dos métodos de caracterização, a Calorimetria diferencial de varrimento e a Difração de Raios-X, para uma melhor compreensão das dispersões sólidas à base de amido. Os dados apresentados sugerem que a maiores rotações e com mais água, os produtos extrudados tornaram-se mais amorfos. Visualmente, a maioria das amostras exibia uma cor branca opaca homogénea, característica de um material cristalino. Os resultados da difratometria das dispersões sólidas de Ibuprofeno e Carbamazepina indicam que permaneceram na sua forma cristalina. Os termogramas, que exibem um pico endotérmico, indicam de que o Ibuprofeno permaneceu cristalino. Este trabalho permitiu uma melhor compreensão do processo de extrusão a quente, dos métodos de caracterização do estado sólido e do comportamento de amido extrudado com fármacos. Comparando os dois tipos de amidos, o amido de milho revelou-se uma melhor escolha para a produção de dispersões sólidas amorfas.A challenging task for the pharmaceutical industry remains the effort to improve the solubility of poorly water-soluble drugs. The production of amorphous solid dispersions is one of the most promising strategies to enhance the drug release rate and bioavailability of these active pharmaceutical ingredients. The current study explored the production of amorphous solid dispersions with Biopharmaceutical Classification System class II drugs via hot-melt extrusion, an aqueoussolubility enhancement technology, using a natural and eco-friendly polymer such as starch. As model drugs, Ibuprofen and Carbamazepine, categorized as class II drugs (low solubility, high permeability) were formulated with two different starch types, Maize Corn Starch and Waxy Corn Starch. Starch is made of two biopolymers, amylose, a linear macromolecule, and the highly branched amylopectin. Ibuprofen and the addiction of water had plasticizing effects. Prior to extrusion, the physical mixtures were mixed in a tumble blender and Differential Scanning Calorimetry was used to assess the glass transition temperature of both starches. During the extrusion, water was fed into the co-rotating twin-screw with a pump. Then, the samples were dried in an oven at 40°C for ±12h, and grinding was performed through hand grinding and a ball mill. An overview of the solid-state characterization methods, Differential Scanning Calorimetry and X-Ray Powder Diffraction, is put together for a better comprehension of the extrudates’ solid-state. The data presented suggest that at a higher rotation and with more water, the extrudates became more amorphous. The visual evaluation shows most samples exhibited a white opaque homogeneous colour, characteristic of a crystalline material. The diffractograms showed that Ibuprofen and Carbamazepine were embedded in the starch matrix in their crystalline form. The thermograms of Ibuprofen solid dispersions exhibited a single sharp endothermic peak, indicating that the drug remained crystalline. This work allowed for a better insight into the hot-melt extrusion process, the characterization methods and further understanding of the thermodynamic behaviour of hotmelt extruded starches with incorporated drugs. Comparing both starches, Maize Corn Starch revealed itself a better choice to produce amorphous solid dispersions.Com o patrocínio do Department of Pharmaceutical Technology, University of Bonn, German

Evaluation of Novel Particle Detection Methods and their Application to Characterize the Process of Protein Aggregation

The biopharmaceutical sector is one of most promising and profitable sectors in medical treatment of a multitude of severe diseases. Biological molecules, however, lead to new challenges for the manufacturing companies. This thesis focused on one of the main challenges for therapeutic proteins: protein aggregation and the detection of the resulting particles. Within this thesis, three main tasks have been addressed: (1) the evaluation of emerging particle detection and characterization techniques, (2) the evaluation of novel technologies for aggregation and unfolding process characterization and (3) the investigation of the aggregation process of current therapeutic proteins (mABs). For the evaluation of particle detection and characterization techniques for the application on protein samples, the following three techniques have been selected: Nanoparticle tracking analysis (NTA), Tunable resistive pulse (TRPS) and STEP-technology® (space and time-resolved extinction profiles) applied in the LUMiSizer®. All techniques rely on different measurement principles and can be claimed as orthogonal methods. These techniques have been shown to be applicable for polystyrene particle suspensions and showed high agreement for the size and/ or concentration determinations of these particles. In the first step, all techniques have been evaluated in two comparative studies analyzing protein BSA standard particle suspensions and monoclonal antibody suspensions. In a second step, a more detailed evaluation of the NTA and the STEP-technology® was performed for monoclonal antibody samples. For the evaluation of novel technologies for the investigation and characterization of protein unfolding and aggregation processes, the following two techniques have been selected: Zetasizer Helix system and the SwitchSENSE®. The Zetasizer Helix system is an instrument combining dynamic light scattering and Raman spectroscopy. The three measurement modes (sample series, isothermal incubation, temperature ramp) have been successfully evaluated for selected therapeutic mABs. The outcome indicated differences in the aggregation mechanism. The same applies to the thermal ramp experiments. In addition, the obtained melting temperatures and aggregation onset fit to the results of orthogonal methods (DSC, ITF, SwitchSENSE). In conclusion, the Zetasizer Helix is an instrument that is not applicable in a high throughput manner, but it gives valuable information for better understanding the correlation between structural changes and aggregation behavior. The SwitchSENSE® technology is a chip-based analytical platform using a specific DNA-based biosurface system to investigate molecular interactions, such as binding kinetics and affinities or enzymatic activities. Out of the various applications of the SwitchSENSE technology, the following applications were evaluated for therapeutic proteins: protein sizing, protein interaction and thermal melting approaches. The most promising approach was the usage of the SwitchSENSE system as orthogonal method for the characterization of the thermal melting behavior. The combination of sizing step and thermal melting step gave information about the refolding potential. Comparative investigations with DSC and ITF showed good coincidence of unfolding start and melting temperature determinations. The system development and application identification is ongoing and continuous updates are necessary for further potential approaches. For the protein aggregation case studies, three monoclonal antibodies (mAB1, mAB2 and mAB3) have been selected. Following these model systems have been investigated considering their biophysical characterization, stability and aggregation behaviour using established and novel techniques and technologies. For the aggregation studies three approaches have been addressed, temperature ramp experiments, isothermal experiments and further protein stress factors, such as extreme temperature, mechanical stirring, extreme acidic pH, reducing stress. In summary, the results of these case studies describe the stability and aggregation processes of the three monoclonal antibodies. Depending on different stress factors (temperature, pH, reducing conditions, etc.) and different approaches (temperature ramp, isothermal incubation and extreme conditions), molecule specific aggregation mechanisms were postulated. The application of the evaluated technologies in the case studies outline their suitability for practical stability studies.Der Einsatz von Biopharmazeutika ist ein vielversprechender Ansatz für die Behandlung einer Vielzahl von Krankheiten. Diese biologischen Moleküle, bspw. therapeutische Antikörper, führen allerdings zu neuen Herausforderungen, denen sich die Pharmaindustrie stellen muss. Eine Herausforderung von therapeutischen Proteinen sind bspw. Aggregationsprozesse und folglich die Detektion der resultierenden Proteinpartikel mit geeigneten Methoden. Die Ziele dieser Arbeit waren daher die Evaluierung neuaufkommender Techniken für die Partikeldetektion und - charakterisierung, die Evaluierung neuer Technologien zur Untersuchung von Proteinentfaltungs- und Aggregationsprozessen und die Untersuchung des Aggregationsverhalten von drei therapeutischen Modellproteinen (monoklonale Antikörper). Für die Evaluierung neuaufkommender Techniken für die Partikeldetektion wurden drei Technologien untersucht: Nanoparticle Tracking Analysis (NTA), Tunable Resistive Pulse Sensing angewendet in dem Gerät qNano (TRPS) und die STEP-technology® angewendet in dem Gerät LUMiSizer®. Die initiale Vergleichbarkeit der Technologien und der Analyseergebnisse wurde zunächst gezeigt mit Hilfe von Latexpartikel Standard Suspensionen. Die anschließende Analyse von drei BSA (bovine serum albumin) Proteinpartikel Standard Suspensionen (mit nominalen Partikelgröße BSA1~150 nm; BSA2~500 nm und BSA3~750 nm) zeigte, vor allem für die heterogeneren Suspensionen BSA2 und BSA3 mit höherer Polydispersität, schon erste Herausforderungen für die Techniken. Während der TRPS-Analyse (Coulter Counter Prinzip) traten die Blockade der Pore sowie eine Proteinschicht auf der Membran auf. Diese Probleme wurden während der Analyse von gestressten therapeutischen Antikörperproben bestätigt und das TRPS-Gerät wurde für die Anwendung für Proteinproben als ungeeignet bewertet. Für NTA und den LUMiSizer® konnte in einer detaillierten Evaluierung hingegen die Anwendbarkeit demonstriert werden. Das NTA, eine Lichtstreu-basierte Methode, bietet dabei eine quantitative Methode zur Bestimmung der Partikelgrößenverteilung im nanometer-Größenbereich (150 nm bis ca. 1000 nm). Die Herausforderung bildet dabei die Einstellung geeigneter Messparameter (z.B. Detection Threshold). Der LUMiSizer®, eine Photozentrifuge, ist hingegen nicht für Konzentrationsbestimmungen geeignet, ermöglicht allerdings eine non-destruktive Analyse der Partikelgrößenverteilung über den nanometer und mikrometer Größenbereich. Die Herausforderung der Methode ist eine ausreichende Trübung der Probe, um die Partikelbewegung detektieren zu können. Zur Untersuchung von Proteinentfaltungs- und Aggregationsprozessen wurden zwei Technologien evaluiert: der Zetasizer Helix, eine Kombination aus Dynamischer Lichtstreuung und Raman Spektroskopie und die SwitchSENSE Technologie, eine chip-basierter Biosensorplattform. Der Zetasizer Helix ermöglicht die simultane Untersuchung von Partikelbildung (kolloidaler Stabilität) und Proteinstrukturänderungen (konformative Stabilität). Es konnte in dieser Arbeit gezeigt werden, dass dieser Ansatz für Proteinaggregationsstudien gut geeignet ist. Die SwitchSENSE Technologie bietet ein breites Einsatzgebiet. In dieser Arbeit konnte eine orthogonale Methode für die Untersuchung des Entfaltungsprozesses von mABs evaluiert werden. Für weitere Anwendungen zur Untersuchung von Proteinaggregation konnten keine neuen Vorteile durch die Verwendung der SwitchSENSE Technologie aufgezeigt werden. Im dritten Abschnitt der Arbeit wurden Aggregationsprozesse der Modellantikörper mAB1, mAB2 und mAB3 untersucht. Die Proteinsuspensionen wurden zunächst biophysikalisch untersucht, um die kolliodale und konformative Stabilität zu beschreiben. Während mAB1 und mAB2 vergleichbar stabil waren, zeigte mAB3 eine signifikant geringere Stabilität. Anschließend wurden die Aggregationsprozesse unter verschiedenen Stresskonditionen (u.a. Temperaturrampen, isothermer Stress oder extrem saurer pH-Wert) untersucht. Der Aggregationsprozess von mAB1 ist gekennzeichnet durch einen langsamen Verlauf, als rate-limiting Schritt kann der Entfaltungsschritt angenommen werden und der gesamte Prozess scheint entfaltungsgetrieben. Der Aggregationsprozess von mAB2 ist gekennzeichnet durch einen schnellen Verlauf, als rate-limiting Schritt kann die Formation eines irreversiblen Nukleus (Nukleationskontrolliert) angenommen werden und der Einfluss der Entfaltung scheint nach dem Aggregationsstart reduziert. Der Aggregationsprozess von mAB3 scheint hingegen gekennzeichnet durch Selbstassoziation der Monomere, einen schnellen Verlauf und als rate-limiting Schritt kann die Monomeraddition angenommen werden. Zusammenfassend konnten fünf neue Technologien evaluiert und in Aggregationsstudien implementiert werden, um die Aggregationsprozesse/-charakteristika von drei Modellantikörpern zu beschreiben. Die Beschreibung und das Verständnis von Aggregationsprozessen unterstützen die Entwicklung einer stabilen Formulierung von therapeutischen Proteinen und bildet daher einen wertvollen Beitrag für die Entwicklung solcher Biopharmazeutika