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Preclinical evaluation of the possible enhancement of the efficacy of anti-malarial drugs by pheroid technology / Natasha LangleyLangley, Natasha January 2007 (has links)
Malaria is currently one of the most imperative parasitic diseases of the developing world. Current effective treatment options are limited because of increasing drug resistance, treatment cost effectiveness and treatment availability. Novel drug delivery systems are a new approach for increased efficacy in the treatment of the disease. Pheroid™ technology, a proven drug delivery system, in combination with anti-malarial drugs was evaluated in this study. The aim of this study was to evaluate the possible enhancement of the efficacy of the existing anti-malarial drugs in combination with Pheroid™ technology.
The efficacy of existing anti-malarial drugs in combination with Pheroids was investigated in vitro with a chloroquine RB-1-resistant strain of P. falciparum. Two different Pheroid formulations, vesicles and microsponges, were used and the control medium consisted of sterile water for injection. Parasitaemia levels were determined microscopically and expressed as a percentage. An in vivo pilot study was also conducted using the P. berghei mouse model. The mice were grouped into seven batches of three mice each. The control group was treated with a Pheroid vesicle formulation only. Three of the groups were treated with three different concentrations of chloroquine dissolved in water namely 2 mg/kg; 5 mg/kg and 10 mg/kg bodyweight (bw) respectively, while the other three groups received the same three concentrations of chloroquine entrapped in Pheroid vesicle formulations. The measure of parasite growth inhibition (percentage parasitaemia), the survival rates and the percentage chemosuppresion was determined. In the in vivo study, all concentrations of chloroquine entrapped in Pheroid vesicles showed suppressed parasitaemia levels up to 11 days post infection. From day 11, the parasitaemia increases rapidly and becomes higher than that in groups treated with chloroquine in water. Chloroquine entrapped in Pheroid vesicles showed improved activity against a chloroquine resistant strain (RB-1) in vitro. The efficacy was enhanced by 1544.62%. The efficacy of mefloquine, artemether and artesunate in Pheroid microsponges were enhanced by 314.32%, 254.86% and 238.78% respectively. It can be concluded that Pheroid™ technology has potential to enhance the efficacy of anti-malaria drugs. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2008.
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Population pharmacokinetics of artesunate and its active metabolite dihydroartemisininTan, Bee San 01 December 2009 (has links)
Artemisinin compounds are the most potent anti-malarial drugs available in the market. Today, malaria treatment is largely relies on the artemisinin-based combination therapies. Artesunate (AS) is the most widely used artemisinin derivative.
In this thesis, we characterized the population pharmacokinetics of AS and its active metabolite dihydroartemisinin (DHA) following oral administration of AS in different populations. In Chapter II, we developed a population pharmacokinetic model of AS and DHA in healthy subjects. These subjects received either single- or multiple-dosing of oral AS, as a monotherapy regimen or in combination with pyronaridine, with or without food. In Chapter III, we developed a population pharmacokinetic model of AS and DHA in adult and pediatric patients with uncomplicated falciparum and vivax malaria who were administered oral pyronaridine/artesunate combination once daily for 3 days.
We modeled the AS and DHA data simultaneously using a parent-metabolite model that assumed complete conversion of AS to DHA. Following oral administration, AS is rapidly absorbed with maximum concentrations reached at about 0.5 hours post-dose. AS is rapidly converted to DHA. DHA then undergoes rapid metabolism, with an elimination half-life of about 0.8 hours in malarial patients. Inter-individual variability for almost all pharmacokinetic parameters and residual variability for both compounds were estimated by the models. Substantial variability was seen in the pharmacokinetic parameters between the subjects.
In healthy subjects, intake of food with the dose was found to delay the absorption of AS significantly, but not the extent of absorption. Weight was also included in this model as a determinant of DHA clearance. When modeling the data from patients, we included weight as part of the model a prioria priori using an established allometric function. No other covariates examined in the analysis were statistically significant.
The performance of final models was evaluated using non-parametric bootstrap technique and visual predictive check. The models were found to adequately described the data at hand, and robust with sufficient predictive power. The results can be used as the base to develop a population pharmacokinetic-pharmacodynamic model and as prior information in guiding the selection of optimal sampling schedule for future pharmacokinetic studies of AS.
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Population pharmacokinetics of artesunate and dihydroartemisinin in children and pregnant women with malariaMorris, Carrie Ann 01 July 2014 (has links)
Artemisinin derivatives are key to the current global treatment approach for malaria. However, much remains unknown regarding the pharmacokinetics of these agents, particularly in children and pregnant women, two groups highly vulnerable to development of severe malaria infection. In this thesis, nonlinear mixed effects modeling is used to characterize the pharmacokinetics of the artemisinin derivative artesunate and its active metabolite, dihydoartemisinin (DHA), in children and in pregnant women.
Chapter 1 of this thesis contains a general review of the clinical pharmacokinetic findings for artesunate and DHA following artesunate administration by the intravenous, intramuscular, oral and rectal routes. Chapter 2 presents a population pharmacokinetic model utilizing both pediatric and adult data from one Phase II and four Phase III clinical trials evaluating the combination agent pyronaridine tetraphosphate/artesunate. The focus of the modeling described in this chapter is the evaluation of the effects of body size and gender on the pharmacokinetics of artesunate and DHA in pediatric patients with uncomplicated malaria. Chapter 3 consists of a population pharmacokinetic model built utilizing plasma artesunate and DHA concentrations from 26 parasitemic second and third trimester pregnant women and 25 parasitemic non-pregnant female controls in the Democratic Republic of Congo who received 200 mg oral artesunate.
The model described in Chapter 2 is a simultaneously implemented parent-metabolite model consisting of a one compartment model for artesunate, a one compartment model for DHA, and first-order artesunate absorption. Various approaches for incorporating body size on artesunate and DHA apparent clearance and volume of distribution parameters were evaluated, with a linear body surface area model and an allometric scaling model both proving satisfactory. The effect of gender was modeled on artesunate and DHA apparent clearance and volume terms. Only the effect of gender on DHA apparent clearance could be estimated with reasonable precision, with the 95% confidence interval for the effect being almost wholly contained within the predefined 0.75 to 1.25 no relevant clinical effect interval. The model described in Chapter 3 consists of a one compartment model for artesunate, a one compartment model for DHA, and mixed zero-order, lagged first order absorption of artesunate. In this model, pregnancy was found to have a marked effect on DHA apparent clearance, with a pregnancy-associated increase in DHA apparent clearance of 42.3%.
The models described in this thesis indicate that, for a given mg/kg dose of artesunate, both young children and pregnant women would be expected, on average, to display lower DHA concentrations than would be observed following administration of the same mg/kg dose to non-pregnant adults. Suboptimal dosing has clinical implications for the individual as well as potential implications regarding parasite susceptibility. Given this, the findings of the research described in this thesis highlight the necessity of investigations designed to comprehensively characterize the pharmacokinetics of artesunate and DHA in these two highly susceptible populations.
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Preclinical evaluation of the possible enhancement of the efficacy of anti-malarial drugs by pheroid technology / Natasha LangleyLangley, Natasha January 2007 (has links)
Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2008.
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Preclinical evaluation of the possible enhancement of the efficacy of anti-malarial drugs by pheroid technology / Natasha LangleyLangley, Natasha January 2007 (has links)
Malaria is currently one of the most imperative parasitic diseases of the developing world. Current effective treatment options are limited because of increasing drug resistance, treatment cost effectiveness and treatment availability. Novel drug delivery systems are a new approach for increased efficacy in the treatment of the disease. Pheroid™ technology, a proven drug delivery system, in combination with anti-malarial drugs was evaluated in this study. The aim of this study was to evaluate the possible enhancement of the efficacy of the existing anti-malarial drugs in combination with Pheroid™ technology.
The efficacy of existing anti-malarial drugs in combination with Pheroids was investigated in vitro with a chloroquine RB-1-resistant strain of P. falciparum. Two different Pheroid formulations, vesicles and microsponges, were used and the control medium consisted of sterile water for injection. Parasitaemia levels were determined microscopically and expressed as a percentage. An in vivo pilot study was also conducted using the P. berghei mouse model. The mice were grouped into seven batches of three mice each. The control group was treated with a Pheroid vesicle formulation only. Three of the groups were treated with three different concentrations of chloroquine dissolved in water namely 2 mg/kg; 5 mg/kg and 10 mg/kg bodyweight (bw) respectively, while the other three groups received the same three concentrations of chloroquine entrapped in Pheroid vesicle formulations. The measure of parasite growth inhibition (percentage parasitaemia), the survival rates and the percentage chemosuppresion was determined. In the in vivo study, all concentrations of chloroquine entrapped in Pheroid vesicles showed suppressed parasitaemia levels up to 11 days post infection. From day 11, the parasitaemia increases rapidly and becomes higher than that in groups treated with chloroquine in water. Chloroquine entrapped in Pheroid vesicles showed improved activity against a chloroquine resistant strain (RB-1) in vitro. The efficacy was enhanced by 1544.62%. The efficacy of mefloquine, artemether and artesunate in Pheroid microsponges were enhanced by 314.32%, 254.86% and 238.78% respectively. It can be concluded that Pheroid™ technology has potential to enhance the efficacy of anti-malaria drugs. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2008.
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Déploiement d’une nouvelle stratégie de traitement d’une maladie à transmission vectorielle : application au paludisme, analyse des pratiques thérapeutiques, et conséquences sur l’épidémiologie de P. falciparum en Casamance, Sénégal, 1996 - 2009 / Implementation of a new treatment strategy for a vector-born parasitic disease : the malaria case, therapeutic practices and consequences on the epidemiology of P. falciparum malaria in Casamance, Senegal, 1996-2009Vaillant, Michel 16 December 2010 (has links)
Le paludisme demeure un des principaux fardeaux de l'humanité en dépit d'une évolution générale favorable du nombre de cas de paludisme. Les travaux contenus dans cette thèse concernent le déploiement d'une combinaison antipaludique à base de dérivés de l'artémisinine en zone rurale à transmission modérée. Le choix du traitement à adopter doit reposer sur l'évidence, dont la forme la plus aboutie demeure la revue systématique et méta-analyse. Cependant, la présentation des résultats peut être améliorée dans le but de faciliter la prise de décision. En outre pour compléter cette preuve expérimentale, il est nécessaire d’étudier l’utilisation des médicaments en pratique courante, dans une approche de médecine factuelle et d’en effectuer le suivi sur plusieurs années concernant l'efficacité, tolérance, sensibilité in vitro, qualité de la prise en charge, épidémiologie du paludisme.Un programme pilote de prise en charge du paludisme intégré dans le système de santé publique a été mis en place au dispensaire de Mlomp, Sénégal à partir de l’année 2000 : un traitement avec la combinaison artésunate + amodiaquine après confirmation parasitologique (en lieu et place d'un traitement présomptif par mono-thérapie). Ces travaux d'accompagnement de la mise à l'échelle des nouvelles directives de prise en charge du paludisme ont permis d'apporter des éléments pour améliorer la qualité des soins ainsi que permettre une meilleure compréhension des obstacles à la mise en place de la nouvelle stratégie et ses effets sur la santé de la population. / Malaria remains a major health burden for mankind despite trends towards a decrease in the number of cases in most endemic areas. The research summarized in this thesis concerns the deployment of an artemisinin-containing antimalarial drug combination (ACT) in a rural district of moderately intense transmission. The choice of an adapted treatment must be evidence based. Systematic reviews and meta-analysis are considered the most robust form of evidence. However, visual displays should be improved in order to improve decision making.Furthermore, to complement evidence from clinical trials, drugs should be studied when used in real-life conditions and followed-up over time for their efficacy, safety, parasite susceptibility, quality of case management, malaria epidemiology.A pilot programme to change case management modalities was started in 2000 in Mlomp, Senegal. The programme was embedded in the public health system and aimed at replacing the previous policy (single-agent treatment on clinical grounds) with the new policy (ACT for parasitologically confirmed malaria). The work conducted to support the scaling-up of the new policy allows improving case management and provides elements towards a better understanding of obstacles to the deployment of the new strategy and its effects on the health of populations.
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High shear melt granulation como alternativa de processo para granulação de artesunato / High-shear melt granulation as an alternative process of artesunate granulationGuimarães, Thiago Frances 07 October 2016 (has links)
A modernização dos equipamentos de granulação por via úmida permitiu o desenvolvimento de diversas técnicas a partir do método tradicional. Dentre as técnicas desenvolvidas, a granulação por solidificação de materiais fundidos (GSMF) elimina o uso de solventes e diminui o tempo de processo. O presente trabalho teve por objetivo estudar o processo de granulação por solidificação de materiais fundidos usando um misturador/granulador do tipo high-shear (HSMG) e avaliar a influência das variáveis do processo nas características farmacotécnicas dos granulados e comprimidos obtidos. O artesunato foi escolhido para realização do estudo de granulação devido ao seu alto grau de cristalinidade e instabilidade química. Foi realizado um estudo de compatibilidade fármaco-excipiente usando técnicas de DSC, FTIR associada a técnicas estatísticas multivariadas (PCA e HCA) e cromatografia líquida de alta eficiência. Os parâmetros de HSMG estudados foram o tipo de diluente, a quantidade de PEG 6000 adicionada, o tempo de massificação, a velocidade do misturador e a velocidade do chopper, usando um planejamento experimental fatorial fracionário 25-1. Os granulados obtidos foram avaliados quanto a densidade, propriedades de fluxo e distribuição granulométrica. Os granulados de manitol apresentaram teor de umidade <1% e span de 1,690. Aqueles com lactose apresentaram teor de umidade > 2% e span de 2,814. A velocidade do misturador e do chopper não apresentaram efeitos significativos nas características dos granulados. O manitol foi escolhido como diluente para o artesunato que foi granulado com misturador a 100 rpm e chopper em 1000 rpm seguindo planejamento experimental fatorial completo 32 em duplicata para estudar variáveis de formulação: a razão artesunato/manitol e a quantidade de PEG 6000 adicionada. A quantidade PEG 6000 adicionada aos granulados contribuiu para o aumento da densidade (aparente e compactada) e do tamanho de partícula, e também para a diminuição da friabilidade, da formação de finos e do span. O perfil compressional dos granulados foi determinado graficamente através das curvas força-tempo e força-deslocamento. O tempo de desintegração dos comprimidos obtidos aumentou com a quantidade de artesunato na formulação enquanto a dureza diminuiu. O PEG 6000 aumentou a resistência mecânica e diminuiu o tempo de desintegração. Foram adicionados 2% de croscarmelose às amostras duplicadas e foi observado uma diminuição do tempo de desintegração dos comprimidos obtidos em 70% e o processo de compressão ficou mais uniforme sem alterar outras características do comprimido como resistência mecânica, trabalho útil, trabalho elástico e plasticidade da formulação. / The modernization of the equipment for wet granulation has enabled the development of different techniques from the traditional method. Among the techniques developed, hot - melt granulation eliminates the use of solvents and reduces the process time. The present work aimed to study the process of granulation by solidification of molten materials using a high-shear mixer/granulator (HSMG) and evaluate the influence of process parameters on particle size distribution, flowability and tableting characteristics of material produced. The artesunate was chosen to carry out the granulation study due to its high degree of crystallinity and chemical instability. A drug-excipient compatibility study was performed by DSC, FTIR combined with multivariate statistical techniques (PCA and HCA) and high performance liquid chromatography. The HSMG parameters investigated were the type of diluent, the amount of PEG 6000 added, massification time, the mixer speed and chopper speed, using a fractional factorial experimental design 25-1. Density, flow properties and particle size distribution of the granules were evaluated. The granular mannitol showed moisture content < 1% and span of 1.690. Granular lactose showed moisture content > 2% and span of 2.814. The mixer and chopper speed did not show significant effects on granule characteristics. Mannitol was chosen as more suitable diluent for artesunate. HSMG was carried out with the mixer speed 100 rpm and chopper speed 1000 rpm according to a full factorial experimental design 32 in duplicate to study formulation variables: artesunate/mannitol proportion and the amount of PEG 6000 added. The amount of PEG 6000 added contributed to increase the granules density (bulk and tapped), mean particle size and also to reduce friability, formation of fine particles and span. The granules compressional profile was determined graphically through force-time and force-displacement plots showing differences in work of compaction, compression and elastic recovery. The disintegration time of tablets obtained increased with the amount of artesunate in formulation while the tensile strength decreased. The amount of PEG 6000 increased hardness and decreased disintegration time. To the duplicate samples were added 2% of croscarmellose and a decrease of 70% in disintegration time of tablets was noted and also compression process become more uniform without changing other tablet features as mechanical resistance, compaction, elastic recovery and formulation plasticity.
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Efficacy enhancement of the antimalarial drugs, mefloquine and artesunate, with PheroidTM technology / E. van HuyssteenVan Huyssteen, Este January 2010 (has links)
Malaria is currently one of the most imperative parasitic diseases in developing countries. Artesunate has a short half-life, low aqueous solubility and resultant poor and erratic absorption upon oral administration, which translate to low bioavailability. Mefloquine is eliminated slowly with a terminal elimination half-life of approximately 20 days and has neuropsychiatric side effects. Novel drug delivery systems have been utilised to optimise chemotherapy with currently available antimalarial drugs. Pheroid™ technology is a patented drug delivery system which has the ability to capture, transport and deliver pharmaceutical compounds. Pheroid™ technology may play a key role in ensuring effective delivery and enhanced bioavailability of novel antimalarial drugs. The aim of this study was to evaluate the possible efficacy and bioavailability enhancement of the selected antimalarial drugs, artesunate and mefloquine, in combination with Pheroid™ vesicles.
The in vitro efficacy of artesunate and mefloquine co-formulated in the oil phase of Pheroid™ vesicles and entrapped in Pheroid™ vesicles 24 hours after manufacturing were investigated against a 3D7 chloroquine-sensitive strain of Plasmodium falciparum. Parasitemia (%) was quantified with flow cytometry after incubation periods of 48 and 72 hours. Drug sensitivity was expressed as 50% inhibitory concentration (IC50) values. An in vivo bioavailability study with artesunate and mefloquine was also conducted in combination with Pheroid™ vesicles, using a mouse model. A sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to analyse the drug levels. C57 BL6 mice were used during this study. The selected antimalarial drugs were administered at a dose of 20 mg/kg with an oral gavage tube. Blood samples were collected by means of tail bleeding.
The in vitro drug sensitivity assays revealed that artesunate, co-formulated in the oil phase of Pheroid™ vesicles and evaluated after a 48 hour incubation period, decreased the IC50 concentration significantly by 90%. Extending the incubation period to 72 hours decreased the IC50 concentration of artesunate, also co-formulated in the oil phase of Pheroid ™ vesicles significantly by 72%. No statistically significant differences between the reference and Pheroid™ vesicle groups were achieved when artesunate was entrapped 24 hours after manufacturing of Pheroid™ vesicles. Mefloquine co-formulated in the oil phase of Pheroid™ vesicles and evaluated after a 48 hour incubation period decreased the IC50 concentration by 36%. Extending the incubation period to 72 hours increased the efficacy of the Pheroid™ vesicles and the IC50 concentration was significantly decreased by 51%. In contrast with the results obtained with artesunate, entrapment of mefloquine in Pheroid™ vesicles 24 hours after manufacturing decreased the IC50 concentration significantly by 66%.
The LC-MS/MS method was found to be sensitive, selective and accurate for the determination of artesunate and its active metabolite, dihydroartemisinin (DHA) in mouse plasma and mefloquine in mouse whole blood. Most of the artesunate plasma concentrations were below the limit of quantification in the reference group and relatively high outliers were observed in some of the samples. The mean artesunate levels of the Pheroid™ vesicle group were lower compared to the reference group, but the variation within the Pheroid™ vesicle group lessened significantly. The mean DHA concentrations of the Pheroid™ vesicle group were significantly higher. DHA obtained a higher peak plasma drug concentration with the Pheroid™ vesicle group (173.0 ng/ml) in relation to the reference group (105.0 ng/ml) and at a much faster time (10 minutes in Pheroid™ vesicles in contrast to 30 minutes of the reference group). Pharmacokinetic models could not be constructed due to blood sampling per animal limitation. The incorporation of mefloquine in Pheroid™ vesicles did not seem to have improved results in relation to the reference group. No statistical significant differences were observed in the pharmacokinetic parameters between the two groups. The relative bioavailability (%) of the Pheroid™ vesicle incorporated mefloquine was 7% less bioavailable than the reference group. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2010.
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Efficacy enhancement of the antimalarial drugs, mefloquine and artesunate, with PheroidTM technology / E. van HuyssteenVan Huyssteen, Este January 2010 (has links)
Malaria is currently one of the most imperative parasitic diseases in developing countries. Artesunate has a short half-life, low aqueous solubility and resultant poor and erratic absorption upon oral administration, which translate to low bioavailability. Mefloquine is eliminated slowly with a terminal elimination half-life of approximately 20 days and has neuropsychiatric side effects. Novel drug delivery systems have been utilised to optimise chemotherapy with currently available antimalarial drugs. Pheroid™ technology is a patented drug delivery system which has the ability to capture, transport and deliver pharmaceutical compounds. Pheroid™ technology may play a key role in ensuring effective delivery and enhanced bioavailability of novel antimalarial drugs. The aim of this study was to evaluate the possible efficacy and bioavailability enhancement of the selected antimalarial drugs, artesunate and mefloquine, in combination with Pheroid™ vesicles.
The in vitro efficacy of artesunate and mefloquine co-formulated in the oil phase of Pheroid™ vesicles and entrapped in Pheroid™ vesicles 24 hours after manufacturing were investigated against a 3D7 chloroquine-sensitive strain of Plasmodium falciparum. Parasitemia (%) was quantified with flow cytometry after incubation periods of 48 and 72 hours. Drug sensitivity was expressed as 50% inhibitory concentration (IC50) values. An in vivo bioavailability study with artesunate and mefloquine was also conducted in combination with Pheroid™ vesicles, using a mouse model. A sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to analyse the drug levels. C57 BL6 mice were used during this study. The selected antimalarial drugs were administered at a dose of 20 mg/kg with an oral gavage tube. Blood samples were collected by means of tail bleeding.
The in vitro drug sensitivity assays revealed that artesunate, co-formulated in the oil phase of Pheroid™ vesicles and evaluated after a 48 hour incubation period, decreased the IC50 concentration significantly by 90%. Extending the incubation period to 72 hours decreased the IC50 concentration of artesunate, also co-formulated in the oil phase of Pheroid ™ vesicles significantly by 72%. No statistically significant differences between the reference and Pheroid™ vesicle groups were achieved when artesunate was entrapped 24 hours after manufacturing of Pheroid™ vesicles. Mefloquine co-formulated in the oil phase of Pheroid™ vesicles and evaluated after a 48 hour incubation period decreased the IC50 concentration by 36%. Extending the incubation period to 72 hours increased the efficacy of the Pheroid™ vesicles and the IC50 concentration was significantly decreased by 51%. In contrast with the results obtained with artesunate, entrapment of mefloquine in Pheroid™ vesicles 24 hours after manufacturing decreased the IC50 concentration significantly by 66%.
The LC-MS/MS method was found to be sensitive, selective and accurate for the determination of artesunate and its active metabolite, dihydroartemisinin (DHA) in mouse plasma and mefloquine in mouse whole blood. Most of the artesunate plasma concentrations were below the limit of quantification in the reference group and relatively high outliers were observed in some of the samples. The mean artesunate levels of the Pheroid™ vesicle group were lower compared to the reference group, but the variation within the Pheroid™ vesicle group lessened significantly. The mean DHA concentrations of the Pheroid™ vesicle group were significantly higher. DHA obtained a higher peak plasma drug concentration with the Pheroid™ vesicle group (173.0 ng/ml) in relation to the reference group (105.0 ng/ml) and at a much faster time (10 minutes in Pheroid™ vesicles in contrast to 30 minutes of the reference group). Pharmacokinetic models could not be constructed due to blood sampling per animal limitation. The incorporation of mefloquine in Pheroid™ vesicles did not seem to have improved results in relation to the reference group. No statistical significant differences were observed in the pharmacokinetic parameters between the two groups. The relative bioavailability (%) of the Pheroid™ vesicle incorporated mefloquine was 7% less bioavailable than the reference group. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2010.
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Multiplexed, affordable, and portable platform for real time quantification of counterfeit and substandard medicinesHo, Nga T. 21 June 2016 (has links)
The World Health Organization estimates that about 10-30% of pharmaceuticals in the world are either substandard or counterfeit. The number is even higher in the developing countries. From a public health perspective, a key contributor to the development and proliferation drug resistant strains of infections, including tuberculosis (TB), malaria and other infections that are leading killers in resource limited settings is poor quality medicines. Most of the main causes are profit driven corruption in many pharmaceutical companies, the poor manufacture and quality control, and/or the inappropriate storage conditions. Poor quality drugs lead to loss of life, create morbidity, strain the financial structure of the health system and lead to long-term drug resistance that affects us all.
The current technology for screening poor quality drugs can be divided into 2 categories: the high end, precise and high cost technologies (such as High Performance Liquid Chromatography) and lower cost and qualitative technologies (such as Thin-Layered Chromatography). The high-end methods can give a precise measurement of active pharmaceutical ingredient (API) concentration and the presence of impurities in the tablets, but require trained personnel, advanced machine and lab set up, not suitable for field testing where most of poor quality pharmaceuticals have been found. The lower cost techniques require little training and simple equipment to operate at a relatively inexpensive price, but only gives qualitative results. In addition, most of current methods do not look at the dissolution profile of the tablets simultaneously with the concentration of API. Therefore, we propose to develop an assay that can quantify the concentrations of multiple APIs simultaneously and measure dissolution rates.
In order to address current gaps in knowledge, my research proposal has three main parts in the assay development: 1) Development of an fluorescent/luminescent assay for detection of counterfeit/substandard antimalarial using small-molecules-based methods and field testing in Ghana; 2) Development of a fluorescent assay for detection of water-soluble pharmaceuticals using SELEX; and 3) Design a detection platform using microfluidic chips for real time quantification of multiple active pharmaceutical ingredients. For proof-of-concept, an antimalarial drug (artesunate and amodiaquine) and antibacterial antibiotics (sulfamethoxazole and trimethoprim) are selected to demonstrate the probe development and test the chip performance. Overall, the assay will be rapid, robust, portable, inexpensive, multiplexed, quantitative, specific, and sensitive. At a big picture level, emphasizing drug quality and creating robust mechanisms of drug testing will improve health outcomes and enhance treatment efficacy in resource limited settings.
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