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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Rôle des ingrédients et des conditions de cuisson dans la qualité et réactivité des produits céréaliers : le cas du furane et des composés odorants dans la génoise / How ingredients and baking conditions impact quality and reactivity : the case of furan and aroma generation in sponge cake

Cepeda-Vázquez, Mayela 01 December 2017 (has links)
L'un des défis actuels de la chimie alimentaire est de développer des produits avec une qualité sanitaire et sensorielle optimale. Ceci est particulièrement important dans les produits traités thermiquement, tels que les produits céréaliers. Lors de la cuisson et à partir des ingrédients, un nombre considérable de composés peuvent se former. Certains suscitent une préoccupation sanitaire émergente, lorsque d'autres jouent un rôle sensoriel indéniable. Comprendre la réactivité des constituants devient alors un levier puissant pour développer des voies d'amélioration des aliments. Ce travail porte sur les effets des ingrédients et conditions de cuisson dans la génération de furane, composé possiblement cancérigène, et furfural, composé odorant contribuant à l'arôme caractéristique de la génoise. Afin de maîtriser la réactivité et ainsi optimiser la qualité des produits, une approche globale a été adoptée, incluant l'étude des composés volatils, des propriétés physicochimiques et sensorielles et l'appréciation hédonique des consommateurs. Ce travail propose une méthodologie et ouvre des pistes intéressantes pour développer des stratégies efficaces de maîtrise de la qualité globale des produits transformés. / A current challenge for food chemists consists in developing safe yet appealing food. This is particularly difficult in thermally-treated foods, like baked products, since a great number of compounds may be produced during heating. While some of these are of health concern, others contribute to other key aspects of quality, such as aroma or color, revealing the need of considering reactivity into food quality design. This work deals with the effects of formulation and baking conditions on the generation of furan, a heatinduced contaminant, and furfural, contributing typical aroma to sponge cake. Moreover, a holistic approach was adopted, covering volatile generation, physical properties, sensory evaluation and consumer tests, both for further understanding reactivity and optimizing product quality. This work is certainly an important step towards the development of novel strategies for qualitydriven design of heat-treated food.
32

A Case Study Evaluation of Quality Standards and Online Faculty Development

O'Brien, Erin 01 January 2015 (has links)
This dissertation in practice was designed to provide an evaluation case study of two institutions, one college and one university, in the field of online learning and quality assurance. The writer evaluated these two institutions of higher learning to discover what online teaching criteria are required and what quality assurance processes are being used to assess the quality of the institutions* online courses. An analysis of the data revealed that both institutions were at the appropriate stage of development, support, training and quality assurance measures for their sizes, online populations and for the length of time they have been involved in online learning. Findings revealed that both institutions had a quality assurance process in place that is appropriate to their location, population and faculty. There is much to be learned by examining the two different credentialing and quality assurance approaches to online teaching and learning that these two different institutions employ for anyone interested in improving their institutions* processes.
33

Evaluation of the critical parameters and polymeric coat performance in compressed multiparticulate systems

Benhadia, Abrehem M.A. January 2019 (has links)
Compression of coated pellets is a practical alternative to capsule filling. The current practice is to add cushioning agents to minimize the stress on the coated pellets. Cushioning agents however add bulkiness and reduce the overall drug loading capacity. In this study, we investigated the performance of compressed coated pellets with no cushioning agent to evaluate the feasibility of predicting the coat behaviour using thermo-mechanical and rheological analysis techniques. Different coating formulations were made of ethyl cellulose (EC) as a coating polymer and two different kinds of additives were incorporated into the polymeric coating solution. Triethyl Citrate (TEC) and Polyethylene glycol 400(PEG400) were used as plasticizers at different levels to the coating formulations (10%, 20%, 30%). Thermal, mechanical and rheological measurements of the coating film formulations were achieved to investigate the effect of plasticizers. Thermal gravimetric analysis results (TGA) showed higher residual moisture content in films plasticised with PEG 400 compared to their TEC counterparts. Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA) and Parallel Plate Shear Rheometer (PPSR) were used to study the influence of the level and type of plasticisers incorporated in coating film formulation on the performance of the coating film. In this study, both DSC and DMA were used to investigate the Tg for each film coating formulation in order to evaluate the effect of the additives. In general DMA results for the Tg value of the films were always higher by 10-20% than those measured by the DSC. Furthermore, clamp size and the frequency of the oscillation have an influence on the evaluation of Tg. Complex viscosity for different coating film formulations revealed that the shear hinning gradient changes with temperature and plasticiser type and concentration. The value of complex viscosity from DMA and PPSR exhibits power law behaviour. The rheological moduli were indirectly affected by the level of plasticiser. There was a discrepancy between the complex viscosity results obtained from both DMA and PPSR at similar temperature but they follow the same trend. The non plasticized polymer showed a 10 time higher complex viscosity values when measured by DMA over that measured by PPSR. The difference was smaller in plasticized films but it was not consistent. Therefore a consistent coefficient to correlate the DMA and PPSR couldn’t be accurately determined Coated pellets were compressed and key process parameters were evaluated. The obtained results revealed that the coating thickness has a significant effect on the release profile of the final products. It was found that by increasing the coating film thickness, the percentage released decreased. Also the compression force has lower influence on the drug release profile, while the dwell time has very low effect on the percentage release from the final products. Optimum release profile was obtained at a coating level of 5.5% w/w and a compression force of 4700N In conclusion, the elasticity of the plasticised EC films in this study meant that the internal stress is not dissipated during compression and the dwell time range that was used in this experiment. Increasing the thickness therefore was necessary to enhance the strength of the film and avoid cracking. The mechanical and rheological profiling was helpful therefore to understand the behaviour of the coated pellets and predict the film properties at various steps of the process of coating and compression (i.e., various shear rate regimes). Experimental design approach to studying the key process and formulation parameters helped identify the optimum values for the process.
34

A Process Analytical Technology (PAT) approach involving near infrared spectroscopy to control the manufacturing of an active pharmaceutical ingredient : development, validation and implementation

Schaefer, Cédric 11 July 2013 (has links)
Les entreprises pharmaceutiques ont progressivement adopté le concept de Process Analytical Technology (PAT) afin de contrôler et d'assurer en temps réel la qualité des produits pharmaceutiques au cours de leur production. Le PAT et un composant central du concept plus général de Quality-by-Design (QbD) promu par les agence régulatrices et visant à construire la qualité des produits via une approche scientifique et la gestion des risques.Une méthode basée sur la spectroscopie proche infrarouge (PIR) a été développée comme un outil du PAT pour contrôler en ligne la cristallisation d'un principe actif pharmaceutique. Au cours du procédé les teneurs en principe actif et en solvant résiduel doivent être déterminées avec précision afin d'atteindre un point d'ensemencement prédéfini. Une méthodologie basée sur les principes du QbD a guidé le développement et la validation de la méthode tout en assurant l'adéquation avec son utilisation prévue. Des modèles basés sur les moindres carrés partiels ont été construits à l'aide d'outils chimiométriques afin de quantifier les 2 analytes d'intérêt. La méthode a été totalement validée conformément aux requis officiels en utilisant les profils d'exactitude. Un suivi du procédé en temps réel a permis de prouver que la méthode correspond à son usage prévu.L'implémentation de cette méthode comme à l'échelle industrielle au lancement de ce nouveau procédé permettra le contrôle automatique de l'étape de cristallisation dans le but d'assurer un niveau de qualité prédéfini de l'API. D'autres avantages sont attendus incluant la réduction du temps du procédé, la suppression d'un échantillonnage difficile et d'analyses hors ligne fastidieuses. / Pharmaceutical companies are progressively adopting and introducing the Process Analytical Technology (PAT) concept to control and ensure in real-time product quality in development and manufacturing. PAT is a key component of the Quality-by-Design (QbD) framework promoted by the regulatory authorities, aiming the building of product quality based on both a strong scientific background and a quality risk management approach.An analytical method based on near infrared (NIR) spectroscopy was developed as a PAT tool to control on-line an API (active pharmaceutical ingredient) crystallization. During this process the API and residual solvent contents need to be precisely determined to reach a predefined seeding point. An original methodology based on the QbD principles was applied to conduct the development and validation of the NIR method and to ensure that it is fitted for its intended use. Partial least squares (PLS) models were developed and optimized through chemometrics tools in order to quantify the 2 analytes of interest. The method was fully validated according to the official requirements using the accuracy profile approach. Besides, a real-time process monitoring was added to the validation phase to prove and document that the method is fitted for purpose.Implementation of this method as an in-process control at industrial plant from the launch of this new pharmaceutical process will enable automatic control of the crystallization step in order to ensure a predefined quality level of the API. Other valuable benefits are expected such as reduction of the process time, and suppression of a difficult sampling and tedious off-line analyzes.
35

Development and evaluation of a solid oral dosage form for an artesunate and mefloquine drug combination / Abel Hermanus van der Watt

Van der Watt, Abel Hermanus January 2014 (has links)
Malaria affects about forty percent of the world’s population. Annually more than 1.5 million fatalities due to malaria occur and parasite resistance to existing antimalarial drugs such as mefloquine has already reached disturbingly high levels in South-East Asia and on the African continent. Consequently, there is a dire need for new drugs or formulations in the prophylaxis and treatment of malaria. Artesunate, an artemisinin derivative, represents a new category of antimalarials that is effective against drug-resistant Plasmodium falciparum strains and is of significance in the current antimalarial campaign. As formulating an ACT double fixed-dose combination is technically difficult, it is essential that fixed-dose combinations are shown to have satisfactory ingredient compatibility, stability, and dissolution rates similar to the separate oral dosage forms. Since the general deployment of a combination of artesunate and mefloquine in 1994, the cure rate increased again to almost 100% from 1998 onwards, and there has been a sustained decline in the incidence of Plasmodium falciparum malaria in the experimental studies (Nosten et al., 2000:297; WHO, 2010:17). However, the successful formulation of a solid oral dosage form and fixed dosage combination of artesunate and mefloquine remains both a market opportunity and a challenge. Artesunate and mefloquine both exhibited poor flow properties. Furthermore, different elimination half-lives, treatment dosages as well as solubility properties of artesunate and mefloquine required different formulation approaches. To substantiate the FDA’s pharmaceutical quality by design concept, the double fixed-dose combination of artesunate and mefloquine required strict preliminary formulation considerations regarding compatibility between excipients and between the APIs. Materials and process methods were only considered if theoretically and experimentally proved safe. Infrared absorption spectroscopy (IR) and X-ray powder diffraction (XRPD) data proved compatibility between ingredients and stability during the complete manufacturing process by a peak by peak correlation. Scanning Electron Micrographs (SEM) provided explanations for the inferior flow properties exhibited by the investigated APIs. Particle size analysis and SEM micrographs confirmed that the larger, rounder and more consistently sized particles of the granulated APIs contributed to improved flow under the specified testing conditions. A compressible mixture containing 615 mg of the APIs in accordance with the WHO recommendation of 25 mg/kg of mefloquine taken in two or three divided dosages, and 4 mg/kg/day for 3 days of artesunate for uncomplicated falciparum malaria was developed. Mini-tablets of artesunate and mefloquine were compressed separately and successfully with the required therapeutic dosages and complied with pharmacopoeial standards. Preformulation studies eventually led to a formula for a double fixed-dose combination and with the specific aim of delaying the release of artesunate due to its short half-life. A factorial design revealed the predominant factors contributing to the successful wet granulation of artesunate and mefloquine. A fractional factorial design identified the optimum factors and factor levels. The application of the granulation fluid (20% w/w) proved to be sufficient by a spraying method for both artesunate and mefloquine. A compatible acrylic polymer and coating agent for artesunate, Eudragit® L100 was employed to delay the release of approximately half of the artesunate dose from the double fixed-dose combination tablet until a pH of 6.8. A compressible mixture was identified and formulated to contain 200 mg of artesunate and 415 mg of mefloquine per tablet. The physical properties of the tablets complied with BP standards. An HPLC method from available literature was adapted and validated for analytical procedures. Dissolution studies according to a USP method were conducted to verify and quantify the release of the APIs in the double fixed-dose combination. The initial dissolution rate (DRi) of artesunate and mefloquine in the acidic dissolution medium was rapid as required. The enteric coated fraction of the artesunate exhibited no release in an acidic environment after 2 hours, but rapid release in a medium with a pH of 6.8. The structure of the granulated particles of mefloquine may have contributed to its first order release profile in the dissolution mediums. A linear correlation was present between the rate of mefloquine release and the percentage of mefloquine dissolved (R2 = 0.9484). Additionally, a linear relationship was found between the logarithm of the percentage mefloquine remaining against time (R2 = 0.9908). First order drug release is the dominant release profile found in the pharmaceutical industry today and is coherent with the kinetics of release obtained for mefloquine. A concept pre-clinical phase, double fixed-dose combination solid oral dosage form for artesunate and mefloquine was developed. The double fixed-dose combination was designed in accordance with the WHO’s recommendation for an oral dosage regimen of artesunate and mefloquine for the treatment of uncomplicated falciparum malaria. The specifications of the double fixed-dose combination were developed in close accordance with the FDA’s quality by design concept and WHO recommendations. An HPLC analytical procedure was developed to verify the presence of artesunate and mefloquine. The dissolution profiles of artesunate and mefloquine were investigated during the dissolution studies. / PhD (Pharmaceutics), North-West University, Potchefstroom Campus, 2014
36

Desenvolvimento de um método indicativo de estabilidade para ondansetrona / Development of a stability indicating method for ondansetron

Maranho, Rafael Finocchiaro 17 October 2017 (has links)
ultravioleta e espectrometria de massas para análise do teor e limite de impurezas e compostos de degradação para o principio ativo farmacêutico ondansetrona e três diferentes formas farmacêuticas foi desenvolvido utilizando conceitos de qualidade analítica por planejamento (aQbD) e validado de acordo com os requerimentos da USP-NF e do ICH. O método desenvolvido apresentou capacidade de separação de vinte compostos detectados nas amostras envolvidas no estudo: o princípio ativo ondansetrona, sete impurezas descritas nos principais compêndios farmacopéicos mundiais (United States Pharmacopeia-National Formulary, European Pharmacopoeia, British Pharmacopoeia e Indian Pharmacopoeia), onze compostos de degradação gerados pelos estudos de estresse e um excipiente. O método final apresentou um tempo de corrida de 14 minutos, com vazão de fase móvel de 0,4 mL/min, detecção de impurezas por ultravioleta a 220 nm e do princípio ativo a 305 nm, com apoio da detecção por espectrometria de massas de alta resolução (QTOF). Em comparação aos métodos requeridos pelas monografias relacionadas à ondansetrona publicadas nos compêndios farmacopéicos citados, o método desenvolvido apresenta uma alternativa eficiente e econômica para a análise de rotina de diferentes formas da matéria-prima ondansetrona (base, cloridrato, diferentes níveis de hidratação) e formas farmacêuticas (comprimidos, comprimidos de desintegração oral e solução injetável), mostrando que a modernização dos métodos cromatográficos, além de garantir a qualidade dos produtos farmacêuticos e promover a saúde da população, tem um impacto relevante na economia da produção e análise de medicamentos e na diminuição do impacto ao meio ambiente / An analytical method by ultraperformance liquid chromatography and detection by UV and mass spectrometry for assay and limit test for impurities and degradation compounds for the active pharmaceutical ingredient ondansetron and three different pharmaceutical products was developed using the analytical Quality by Design (aQbD) approach, and was validated according to the USP-NF and ICH requirements. The analytical method was efficient for the separation of twenty different compounds, detected in the samples involved in this study: the active ingredient ondansetron, seven impurities mentioned in the main global pharmacopeial compendia (United States Pharmacopeia-National Formulary, European Pharmacopoeia, British Pharmacopoeia e Indian Pharmacopoeia), eleven degradation compounds detected in the samples from stress studies and one excipient. The final method was composed by a 14 minutes run, using mobile phase flow at 0.4 mL/min, detection by UV at 220 nm for the impurities and degradation compounds and at 305 nm for ondansetron, supported by the high-resolution mass spectrometry detection (QTOF). Comparing the method developed with the chromatographic methods required by the monographs related to ondansetron published in the mentioned pharmacopeial compendia, it represents an efficient and economic alternative to the routine analysis of different ondansetron raw material forms (base, hydrochloride, different hydrates) and pharmaceutical products (tablets, orally disintegrating tablets and injectable), demonstrating the importance of the modernization of analytical procedures, with regard to not only the quality assurance of pharmaceutical products and promotion of public health, but also to the positive impact on the economy and sustainability of the pharmaceutical analysis and manufacturing.
37

Desenvolvimento de um método indicativo de estabilidade para ondansetrona / Development of a stability indicating method for ondansetron

Rafael Finocchiaro Maranho 17 October 2017 (has links)
ultravioleta e espectrometria de massas para análise do teor e limite de impurezas e compostos de degradação para o principio ativo farmacêutico ondansetrona e três diferentes formas farmacêuticas foi desenvolvido utilizando conceitos de qualidade analítica por planejamento (aQbD) e validado de acordo com os requerimentos da USP-NF e do ICH. O método desenvolvido apresentou capacidade de separação de vinte compostos detectados nas amostras envolvidas no estudo: o princípio ativo ondansetrona, sete impurezas descritas nos principais compêndios farmacopéicos mundiais (United States Pharmacopeia-National Formulary, European Pharmacopoeia, British Pharmacopoeia e Indian Pharmacopoeia), onze compostos de degradação gerados pelos estudos de estresse e um excipiente. O método final apresentou um tempo de corrida de 14 minutos, com vazão de fase móvel de 0,4 mL/min, detecção de impurezas por ultravioleta a 220 nm e do princípio ativo a 305 nm, com apoio da detecção por espectrometria de massas de alta resolução (QTOF). Em comparação aos métodos requeridos pelas monografias relacionadas à ondansetrona publicadas nos compêndios farmacopéicos citados, o método desenvolvido apresenta uma alternativa eficiente e econômica para a análise de rotina de diferentes formas da matéria-prima ondansetrona (base, cloridrato, diferentes níveis de hidratação) e formas farmacêuticas (comprimidos, comprimidos de desintegração oral e solução injetável), mostrando que a modernização dos métodos cromatográficos, além de garantir a qualidade dos produtos farmacêuticos e promover a saúde da população, tem um impacto relevante na economia da produção e análise de medicamentos e na diminuição do impacto ao meio ambiente / An analytical method by ultraperformance liquid chromatography and detection by UV and mass spectrometry for assay and limit test for impurities and degradation compounds for the active pharmaceutical ingredient ondansetron and three different pharmaceutical products was developed using the analytical Quality by Design (aQbD) approach, and was validated according to the USP-NF and ICH requirements. The analytical method was efficient for the separation of twenty different compounds, detected in the samples involved in this study: the active ingredient ondansetron, seven impurities mentioned in the main global pharmacopeial compendia (United States Pharmacopeia-National Formulary, European Pharmacopoeia, British Pharmacopoeia e Indian Pharmacopoeia), eleven degradation compounds detected in the samples from stress studies and one excipient. The final method was composed by a 14 minutes run, using mobile phase flow at 0.4 mL/min, detection by UV at 220 nm for the impurities and degradation compounds and at 305 nm for ondansetron, supported by the high-resolution mass spectrometry detection (QTOF). Comparing the method developed with the chromatographic methods required by the monographs related to ondansetron published in the mentioned pharmacopeial compendia, it represents an efficient and economic alternative to the routine analysis of different ondansetron raw material forms (base, hydrochloride, different hydrates) and pharmaceutical products (tablets, orally disintegrating tablets and injectable), demonstrating the importance of the modernization of analytical procedures, with regard to not only the quality assurance of pharmaceutical products and promotion of public health, but also to the positive impact on the economy and sustainability of the pharmaceutical analysis and manufacturing.
38

Thermal and rheological approaches for the systematic enhancement of pharmaceutical polymeric coating formulations : effects of additives on glass transition temperature, dynamic mechanical properties and coating performance in aqueous and solvent-free coating process using DSC, shear rheometry, dissolution, light profilometry and dynamic mechanical analysis

Isreb, Mohammad January 2011 (has links)
Additives, incorporated in film coating formulations, and their process parameters are generally selected using a trial-and-error approach. However, coating problems and defects, especially those associated with aqueous coating systems, indicate the necessity of embracing a quality-by-design approach to identify the optimum coating parameters. In this study, the feasibility of using thermal and rheological measurements to help evaluate and design novel coating formulations has been investigated. Hydroxypropyl methylcellulose acetate succinate (HPMCAS), an enteric coating polymer, was used as the film forming polymer. Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA), and Parallel Plate Shear Rheometery (PPSR) were used to evaluate the effect of different plasticisers on the performance of HPMCAS. The results illustrate that, for identical formulations, the DSC and DMA methods yielded up to 40% differences in glass transition temperature (Tg) values. Moreover, Tg measured using loss modulus signals were always 20-30 oC less than those measured using tan delta results in DMA testing. Absolute and relative Tg values can significantly vary depending on the geometry of the samples, clamp size, temperature ramping rate and the frequency of the oscillations. Complex viscosity data for different formulations demonstrated a variable shear thinning behaviour and a Tg independent ranking. It is, therefore, insufficient to rely purely on Tg values to determine the relative performance of additives. In addition, complex viscosity results, obtained using both the DMA and PPSR techniques at similar temperatures, are shown to be comparable. The results from both techniques were therefore used to produce continuous master curves for the HPMCAS formulations. Additionally, step strain tests showed that HPMCAS chains do not fully III disentangle after 105 seconds as predicted by the Maxwell model. Finally, in situ aqueous-based coating experiments proved that mixtures of triethyl acetyl citrate and acetylated monoglyceride (TEAC/AMG), even without cooling of the suspension, do not cause blocking of the spray nozzle whereas triethyl citrate (TEC) based formulae did. TEAC (alone or in a combination with AMG) exhibits superior wettability to HPMCAS than TEC/AMG formulations and can be used to enhance the efficiency and film quality of the dry coating process.
39

Multivariate Synergies in Pharmaceutical Roll Compaction : The quality influence of raw materials and process parameters by design of experiments

Souihi, Nabil January 2014 (has links)
Roll compaction is a continuous process commonly used in the pharmaceutical industry for dry granulation of moisture and heat sensitive powder blends. It is intended to increase bulk density and improve flowability. Roll compaction is a complex process that depends on many factors, such as feed powder properties, processing conditions and system layout. Some of the variability in the process remains unexplained. Accordingly, modeling tools are needed to understand the properties and the interrelations between raw materials, process parameters and the quality of the product. It is important to look at the whole manufacturing chain from raw materials to tablet properties. The main objective of this thesis was to investigate the impact of raw materials, process parameters and system design variations on the quality of intermediate and final roll compaction products, as well as their interrelations. In order to do so, we have conducted a series of systematic experimental studies and utilized chemometric tools, such as design of experiments, latent variable models (i.e. PCA, OPLS and O2PLS) as well as mechanistic models based on the rolling theory of granular solids developed by Johanson (1965). More specifically, we have developed a modeling approach to elucidate the influence of different brittle filler qualities of mannitol and dicalcium phosphate and their physical properties (i.e. flowability, particle size and compactability) on intermediate and final product quality. This approach allows the possibility of introducing new fillers without additional experiments, provided that they are within the previously mapped design space. Additionally, this approach is generic and could be extended beyond fillers. Furthermore, in contrast to many other materials, the results revealed that some qualities of the investigated fillers demonstrated improved compactability following roll compaction. In one study, we identified the design space for a roll compaction process using a risk-based approach. The influence of process parameters (i.e. roll force, roll speed, roll gap and milling screen size) on different ribbon, granule and tablet properties was evaluated. In another study, we demonstrated the significant added value of the combination of near-infrared chemical imaging, texture analysis and multivariate methods in the quality assessment of the intermediate and final roll compaction products. Finally, we have also studied the roll compaction of an intermediate drug load formulation at different scales and using roll compactors with different feed screw mechanisms (i.e. horizontal and vertical). The horizontal feed screw roll compactor was also equipped with an instrumented roll technology allowing the measurement of normal stress on ribbon. Ribbon porosity was primarily found to be a function of normal stress, exhibiting a quadratic relationship. A similar quadratic relationship was also observed between roll force and ribbon porosity of the vertically fed roll compactor. A combination of design of experiments, latent variable and mechanistic models led to a better understanding of the critical process parameters and showed that scale up/transfer between equipment is feasible.
40

Development and evaluation of a solid oral dosage form for an artesunate and mefloquine drug combination / Abel Hermanus van der Watt

Van der Watt, Abel Hermanus January 2014 (has links)
Malaria affects about forty percent of the world’s population. Annually more than 1.5 million fatalities due to malaria occur and parasite resistance to existing antimalarial drugs such as mefloquine has already reached disturbingly high levels in South-East Asia and on the African continent. Consequently, there is a dire need for new drugs or formulations in the prophylaxis and treatment of malaria. Artesunate, an artemisinin derivative, represents a new category of antimalarials that is effective against drug-resistant Plasmodium falciparum strains and is of significance in the current antimalarial campaign. As formulating an ACT double fixed-dose combination is technically difficult, it is essential that fixed-dose combinations are shown to have satisfactory ingredient compatibility, stability, and dissolution rates similar to the separate oral dosage forms. Since the general deployment of a combination of artesunate and mefloquine in 1994, the cure rate increased again to almost 100% from 1998 onwards, and there has been a sustained decline in the incidence of Plasmodium falciparum malaria in the experimental studies (Nosten et al., 2000:297; WHO, 2010:17). However, the successful formulation of a solid oral dosage form and fixed dosage combination of artesunate and mefloquine remains both a market opportunity and a challenge. Artesunate and mefloquine both exhibited poor flow properties. Furthermore, different elimination half-lives, treatment dosages as well as solubility properties of artesunate and mefloquine required different formulation approaches. To substantiate the FDA’s pharmaceutical quality by design concept, the double fixed-dose combination of artesunate and mefloquine required strict preliminary formulation considerations regarding compatibility between excipients and between the APIs. Materials and process methods were only considered if theoretically and experimentally proved safe. Infrared absorption spectroscopy (IR) and X-ray powder diffraction (XRPD) data proved compatibility between ingredients and stability during the complete manufacturing process by a peak by peak correlation. Scanning Electron Micrographs (SEM) provided explanations for the inferior flow properties exhibited by the investigated APIs. Particle size analysis and SEM micrographs confirmed that the larger, rounder and more consistently sized particles of the granulated APIs contributed to improved flow under the specified testing conditions. A compressible mixture containing 615 mg of the APIs in accordance with the WHO recommendation of 25 mg/kg of mefloquine taken in two or three divided dosages, and 4 mg/kg/day for 3 days of artesunate for uncomplicated falciparum malaria was developed. Mini-tablets of artesunate and mefloquine were compressed separately and successfully with the required therapeutic dosages and complied with pharmacopoeial standards. Preformulation studies eventually led to a formula for a double fixed-dose combination and with the specific aim of delaying the release of artesunate due to its short half-life. A factorial design revealed the predominant factors contributing to the successful wet granulation of artesunate and mefloquine. A fractional factorial design identified the optimum factors and factor levels. The application of the granulation fluid (20% w/w) proved to be sufficient by a spraying method for both artesunate and mefloquine. A compatible acrylic polymer and coating agent for artesunate, Eudragit® L100 was employed to delay the release of approximately half of the artesunate dose from the double fixed-dose combination tablet until a pH of 6.8. A compressible mixture was identified and formulated to contain 200 mg of artesunate and 415 mg of mefloquine per tablet. The physical properties of the tablets complied with BP standards. An HPLC method from available literature was adapted and validated for analytical procedures. Dissolution studies according to a USP method were conducted to verify and quantify the release of the APIs in the double fixed-dose combination. The initial dissolution rate (DRi) of artesunate and mefloquine in the acidic dissolution medium was rapid as required. The enteric coated fraction of the artesunate exhibited no release in an acidic environment after 2 hours, but rapid release in a medium with a pH of 6.8. The structure of the granulated particles of mefloquine may have contributed to its first order release profile in the dissolution mediums. A linear correlation was present between the rate of mefloquine release and the percentage of mefloquine dissolved (R2 = 0.9484). Additionally, a linear relationship was found between the logarithm of the percentage mefloquine remaining against time (R2 = 0.9908). First order drug release is the dominant release profile found in the pharmaceutical industry today and is coherent with the kinetics of release obtained for mefloquine. A concept pre-clinical phase, double fixed-dose combination solid oral dosage form for artesunate and mefloquine was developed. The double fixed-dose combination was designed in accordance with the WHO’s recommendation for an oral dosage regimen of artesunate and mefloquine for the treatment of uncomplicated falciparum malaria. The specifications of the double fixed-dose combination were developed in close accordance with the FDA’s quality by design concept and WHO recommendations. An HPLC analytical procedure was developed to verify the presence of artesunate and mefloquine. The dissolution profiles of artesunate and mefloquine were investigated during the dissolution studies. / PhD (Pharmaceutics), North-West University, Potchefstroom Campus, 2014

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