It is an FDA requirement that the“first in human" dose be based on pre-clinical animal model efficacy and safety testing to ensure a safe entry into Phase I clinical trials. Pre-clinical safety and efficacy models range from mouse to non-human primates. Interspecies scaling of pharmacokinetic parameters is therefore important for predicting drug doses in human clinical trials, although it continues to be less than optimal. Understanding the disposition of the compound in different species through in vitro and in vivo experiments is necessary to ensure appropriate species are selected for human estimates. Data for three imaging agents and a pharmacological stress agent (Oncology tumor agent (DPC-A80351), Thrombus agent (DMP-444), Infection agent (RP-517) Pharmacological stress agent (DPC-A78445-00)) that entered clinical trials and an imaging agent being developed (RP845), were assessed for scaling accuracy. Initially, pharmacokinetic data from animal models were used to extrapolate to human though body weight allometric scaling. Subsequently, the impact of adjusting for plasma protein binding and the impact of metabolic stability in the different models were examined. Allometric scaling of animal pharmacokinetic parameters (clearance (CL), half-life (t½) and volume of distribution (Vdss)) achieved a prediction of the human pharmacokinetic parameter within 13 to 109% of the observed values. This prediction was further improved by adjusting for plasma protein binding of the drug, and achieved an estimate within 5 to 57% of the clinically observed values. Since the parent compound was the dominant species (>95%) in the circulation, metabolic stability was not used as a correction factor. Weight based allometric scaling was further examined for an atherosclerotic plaque targeted radiopharmaceutical imaging agent, RP845-Tc-99m, currently in development. Pharmacokinetic parameters were determined in mouse, rat and rabbit followed by allometric scaling to predict the non-human primate values. Differences between predicted versus observed non-human primate Cl, t½ and Vdss were 40%, 52% and 8%, respectively. Correcting for plasma protein binding improved the prediction for Cl and t½ to within 12 and 3 %, respectively. The Vdss prediction, however became less accurate (38% difference). Since blood clearance is the major parameter in predicting human dose, the improvement from 40% to 12% was important. The plasma protein binding adjusted animal data was then used with allometric scaling to predict human CL, t½ and Vdss. The predicted values were 7.6 mL/min/kg, 70.6 minutes and 0.87 L/kg respectively. Based on the predicted human blood clearance and the dose required to image atherosclerosis in a rabbit model, the estimated human dose would be unacceptably high. This demonstrates how allometric scaling can be used in research projects to assess clinical feasibility. The impact of metabolism differences influencing the reliability of various species to predict for man was highlighted by DPC-A78445-00. DPC-A78445-00 is being developed as an alternative to exercise in myocardial perfusion imaging for the evaluation of coronary artery disease. DPC-A78445-00 was rapidly metabolized to the carboxylic acid by mouse and rat blood in vitro and in vivo, however longer stability was observed in the dog. In vitro human blood data was consistent with the dog, suggesting that mouse and rat would not be representative species. DPC-A78445-00 plasma protein binding was at a similar, moderate level in rat, dog and human plasma and metabolism by hepatocytes was similar in dog and human. Phase I human clinical trial testing determined the area under the blood concentration-time curve (AUC) and clearance predicted by the dog were within 32% of the human values. Overall, body weight based allometric scaling of pharmacokinetic parameters from animal models, when corrected for plasma protein binding, yielded reliable predictions of the human pharmacokinetics (within 50%) for radiopharmaceutical imaging agent. However, although predictive scaling from animal data can give insight into feasibility of compounds working in human, it is important to identify species differences with respect to metabolic stability. This allometric scaling method provides an additional tool to better predict doses in human for novel Medical Imaging agents.

Orientador: José Ricardo de Arruda Miranda / Banca: Luciana Aparecida Corá / Banca: Ricardo Brandit de Oliveira / Banca: Cristina Helena dos Reis Serra / Banca: José Ricardo Corrêa Saglietti / Resumo: A avaliação dos parâmetros motores do trato gastrintestinal é condição necessária para caracterizar o comportamento de formas farmacêuticas sólidas administradas pela via oral. A função motora gastrintestinal pode ser alterada em detrimento de doenças, interações com medicamentos ou intervenções cirúrgicas. Essas alterações, por sua vez, podem influenciar diversos processos farmacêuticos e, consequentemente, a biodisponibilidade dos fármacos. Comprimidos são as formas farmacêuticas mais utilizadas na terapia. Para garantir a eficácia e segurança dessas preparações, são necessários testes in vitro que simulam o trato gastrintestinal. Entretanto, não é possível estimar com precisão a influencia dos parâmetros gastrintestinais na liberação do fármaco. Por essa razão, os ensaios in vivo realizados por técnicas não invasivas e inócuas ao indivíduo são necessários, pois permitem monitorar simultaneamente os parâmetros motores e suas interrelações com os processos de liberação e biodisponibilidade dos fármacos. O objetivo desse trabalho foi empregar a técnica de Biosusceptometria AC associada à farmacocinética para avaliar a influência da motilidade gastrintestinal, bem como das alterações induzidas nessa função pela administração prévia de um procinético (Domperidona) e um antimuscarínico (Butilbrometo de Escopolamina). Além disso, foram avaliadas as influências desses parâmetros no processo de liberação e biodisponibilidade de um fármaco modelo (Diclofenaco Sódico) adicionado a comprimidos revestidos / Abstract: The evaluation of gastrointestinal motor parameters is necessary towards characterize the behavior of solid dosage forms orally administered. The gastrointestinal motor function may be altered by diseases, drugs or surgery. These alterations may influence a number of pharmaceutical processes and consequently the bioavailability of drugs. Tablets are the dosage forms most commonly used in therapy. To ensure the efficacy and safety of these formulations, in vitro tests in simulated gastrointestinal conditions are needed. However, such conditions as well as the influence of gastrointestinal parameters on drug release cannot be fully predicted. For these reasons, in vivo studies are realized by noninvasive and harmless techniques, since they allows monitoring gastrointestinal motor parameters and the relationships with drug delivery and bioavailability. The aim of this work was to employ the AC Biosusceptometry to evaluate the influence of gastrointestinal motility as well as the induced changes on this function by previous administration of a prokinetic drug (domperidone) and an antimuscarinic agent (scopolamine butilbromide). In addition, it have been evaluated how these alterations influenced the drug release and bioavailability of a model drug (sodium diclofenac) added to coated tablets / Doutor

MSc Occupational Therapy, Faculty of Health Sciences, University of the Witwatersrand, 2009 / An increase in the prevalence of ASD has led to increased demands on service provision. This questionnaire-based, descriptive study aimed to explore service use and experiences of health and education service delivery by caregivers and their children with ASD in Johannesburg. The sample size was 39. Comparisons were drawn between the experiences of the participants accessing the private and public service sectors. Children were diagnosed at an average age of 4 years; 2 years after the first symptoms were noted by their caregivers. Families accessed a mean of 3 institutions and 6 professionals in seeking diagnosis and treatment. No specific referral patterns could be established. Challenges to service access identified by caregivers included: logistical problems, lack of professional knowledge and experience, poor parental coping and insight, and lack of community support. Solutions identified by the caregivers included: marketing, training, better referral procedures, and establishment of educational facilities.

Theses (Msc.(Med.)(Pharmacy))--University of Limpopo, 2010. / With the availability of Highly Active Antiretroviral Therapy (HAART), one of the limitations of treatment safety is the occurrence of adverse events associated with antiretroviral agents. The aim of this study was to establish whether stavudine dosage reduction prevents toxicity from developing and minimizes the incidence of symptomatic hyperlactataemia/lactic acidosis (LA) in adults female HIV/AIDS infected patients. This retrospective study covered adult patients treated at the adult ARV clinic, Dr George Mukhari Hospital. The records of 88 patients aged between 27 and 59 years, initiated and treated from August 2004 to January 2006, were analyzed ( 67 females and 21 males). Twenty nine females started their treatment on a regimen containing 40 mg stavudine while 38 females were started on 30 mg stavudine. A group of male patients (n=21) were included for comparison. Seven males started on 40 mg stavudine and 14 were on 30 mg stavudine. Ten out of twenty nine females who started treatment on 40 mg stavudine developed elevated lactate levels while nineteen received 30 mg stavudine as reduced dose. Eight out of nineteen further developed elevated lactate levels when on 30 mg stavudine but eleven out of nineteen remained stable on treatment with 30 mg stavudine as reduced dose. In the group started on 30 mg stavudine, thirteen females out of thirty seven developed elevated lactate levels while twenty four were stable on their treatment. Key words: stavudine, dosage reduction, lactate levels, hyperlactataemia, lactic acidosis.

Two manifestations of gene regulation-- dosage compensation and ontogenic regulation--were examined in normally positioned and relocated v+ genotypes in Drosophila melanogaster to determine the role of gene position in these control functions. Enzyme assays, used as criteria of gene activity, were performed on various genotypes containing different doses of v+ in normal and relocated positions in male and female flies. The results indicate that although differently positioned v+ genes may specify different tryptophan pyrrolase activities, they still show dosage compensation. In each case, the enzyme activity associated with each gene, either on the X, Y, or third chromosome, is twice as much in males as it is in females. This indicates that dosage compensation is not confined to the gene when located on the X chromosome. In order to determine if the pattern of activity of the gene during ontogeny is altered by relocation, T(l; 3)rasv genotypes and wild type controls were assayed at the same stages of development. The experimental design allowed a comparison of the ontogenic expression of three different genes--v+, Zw, and Pgd--through the activities of their associated enzymes. The results indicate that changing the gene's position may alter its ontogenic expression. Animals with v+ on the third chromosome have a unique peak of tryptophan pyrrolase activity in larvae which is not present in wild type. The activity in this peak is at l east 10 times higher than that observed in 72-hour wild type larvae, in fact, higher than that observed in any normal genotype at any time during development. With the exception of this peak, the developmental curves of enzyme activity are similar, although the relocated genes specify consistently lower enzyme activities than do normally positioned genes. The unique peak is not the result of a general physiological effect since the patterns of Zw and Pgd activity appear to be the same in wild type and translocated v+ genotypes. The relevance of the data to earlier studies and to models for gene regulation is discussed.

Objectives: To evaluate the influence of pharmacist interventions on drug and dosage prescribing in pediatric settings. Method: Demographic, clinical, and prescribing data and parents’ measurement data were evaluated by pre- and post studies including time series studies and control groups. The data was evaluated against Australian Therapeutic Guidelines. Educational intervention strategies were designed and administered and a post-intervention evaluation was conducted. Group comparisons were made using x2 and Student’s t-test statistics. Time series analysis involved multiple linear regression analysis. Results: The major study involved antibiotics and analgesic drugs and dosages in appendectomy in children. Significant improvements occurred in the selection and dosages of prophylactic antibiotics @<0.001) and in subsequent ward antibiotic treatments @<0.001) also showed marked conformity with the guidelines Other pediatric studies involved liquid medication dosing and prescribing accuracy for paracetamol in a developing country where a simple intervention produced very marked improvements @<0.001). An intervention in severe community-acquired pneumonia showed an improvement in the prescription of appropriate drugs @<0.001) and appropriate dosages of paracetamol (p<O.OOl) according to the guidelines. In drug utilisation evaluation of cefiriaxone, flucloxacillin and Liquigesic COB, there was a significant improvement in the dosage prescribing of ceftriaxone and flucloxacillin and no change in Liquigesic COB following the intervention. O f the total, 38/218 (17%) o f the patients received appropriate post-operative antibiotic dosages. 286/368 (78%) of the analgesic prescriptions and 31/218 (14%) of the patients on postoperative antibiotic choice and dosage that were identified as appropriate in tonsillectomy. / Conclusion: This study has identified deficiencies related to the prescribing of antibiotics and analgesics in children. There was a varied level of improvement in the drug dosage prescribing of pediatricians following the pharmacist educational intervention. Locally developed guidelines are more likely to be accepted and followed than those developed nationally without local input.

Vaccination with immunogenic peptides offers a safe and specific way of inducing protection against pathogens, however as of yet there are no peptide-based vaccines available. The limitations on the therapeutic use of peptides are due to their poor immunogenicity and short life span in vivo. Peptide delivery systems act to circumvent these issues. The aims of this research were to investigate the ability of virus-like particles (VLP) from Rabbit haemmorhagic disease virus (RHDV) to deliver immunogenic peptides, to characterize the immune response to these particles, and to investigate whether baculovirus could also act as a delivery system. The vaccine peptides HAT (representing a T helper cell epitope) and HAB (representing the major B cell epitope) derived from the haemagglutinin antigen of influenza virus A/PR/8/34 were used as a model to investigate the ability of these virus particles to act as delivery vehicles to the immune system. A scheme for the production and purification of RHDV VLP was established. Expression of the capsid protein from RHDV in a serum-free recombinant baculovirus system using suspension cultures of up to 200 ml, and separation by isopycnic centrifugation on cesium chloride gradients led to high yields of purified RHDV VLP. Up to 20 mg of pure VLP could be obtained from an 800 ml culture of insect cells infected with recombinant baculovirus. In vitro testing revealed that RHDV VLP carrying the peptide HAT as a genetic fusion were processed by dendritic cells (DC), and that this peptide could be presented to induce activation of T cells. However, the purified RHDV VLP alone were not able to induce significant upregulation of cell activation markers CD40, CD86, and CD80. A preliminary in vivo study revealed that when RHDV VLP carrying the HAT peptide were delivered by an intraperitoneal injection in the absence of adjuvant, the immune response to the peptide was weak, therefore the route of delivery and the use of immune adjuvants with the VLP were optimised. Five different routes of delivery and two different immune adjuvants were compared. VLP were delivered through subcutaneous, intraperitoneal, transcutaneous, intramuscular and intranasal routes. Delivery of the VLP through each of these routes resulted in potent serum antibody responses. However, the strongest antibody responses were elicited when the VLP were delivered through the intraperitoneal or intranasal routes. Of these two routes, intranasal delivery gave the best mucosal responses at the lung surface, and was therefore chosen as the route of delivery for subsequent trials. CpG DNA and the wild-type baculovirus Autographa californica nucleopolyhedrovirus (AcMNPV) were tested as adjuvants for the RHDV VLP. These two adjuvants gave similar results, both acting to enhance a T[H]1 type response against the VLP, characterized by significantly increased levels of serum IgG2a and enhanced IFN-γ production. Two approaches were then tested: using the RHDV VLP as a peptide carrier with a CpG adjuvant, and using baculovirus particles directly as self-adjuvanting carriers for vaccine peptides. HAT and HAB peptides were chemically coupled to RHDV VLP. Mice that were vaccinated with these VLP mixed with a CpG adjuvant were able to raise low levels of specific antibody in the serum against influenza, and specific IgA against influenza was detected in the lung. These results indicated that, though the immune responses raised were modest, the RHDV VLP was able to deliver the vaccine peptides to the immune system. HAT and HAB peptides were chemically coupled to baculovirus particles. When mice were immunized with the baculovirus carrying the vaccine peptides, they raised significant levels of IgG1 (p<0.001) and IgG2a (p<0.05) against influenza in the serum, when compared to peptide delivered alone. A significant level of influenza-specific IgA was also detected in the lung at 10 ng/ml in the mice that received the baculovirus coupled with peptide. Analysis of splenocyte cytokines showed that these mice also responded to restimulation with IFN-γ production at around 100 pg/ml. This research revealed that RHDV VLP are able to act as carriers for vaccine peptides, however there are some limitations to their use with the HAT and HAB model peptides. It also showed that baculovirus can be rapidly modified to carry vaccine peptides by chemical conjugation, and that these peptides can be delivered to induce specific systemic and mucosal immunity, raising both B cell and cell mediated responses. Both virus particles have potential as components for new strategies for vaccination.

La plupart des procédés de synthèse conduisent à des mélanges de produits et l'analyse de ces mélanges est une étape essentielle en chimie. Deux aspects importants en sont le dosage d'un composé d'intéret et son extraction du mélange. Les chimistes ont à leur disposition de nombreuses méthodes d'analyse dont le critère de reconnaissance est une propriété physicochimique. Ici les espèces constituant le mélange sont décrites comme des espèces réactives, caractérisées par leurs propriétés cinétiques. Le but de la thèse était de développer des méthodes théoriques de dosage et d'extracion, réalisables expérimentalement, permettant de singulariser, au sein d'un mélange, un système chimique caractérisé par ses propriétés dynamiques. Les systèmes considérés sont des réseaux de réactions chimiques linéaires et des réactions chimiques non linéaires. Leur dynamique est décrite à une échelle macroscopique. L'originalité de ce travail théorique est de mettre en évidence des phénomènes de résonance déterministe dans l'espace des constantes cinétiques, pour les systèmes simples, ou dans l'espace de paramètres dynamiques choisis, pour les réseaux. Dans cette approche, contrairement à la résonance déterministe classique, la fréquence de l'excitation est fixe et les paramètres dynamiques varient.

Les aciers THLE ont la particularité de posséder à la fois une bonne ductilité et de hautes caractéristiques mécaniques. Ceci les rend particulièrement adaptés pour l'industrie automobile, dont les principales exigences sont l'allègement du véhicule et la sécurité des passagers. Toutefois, il est bien connu que l'augmentation des caractéristiques mécaniques accroît la susceptibilité à la fragilisation par l'hydrogène. Ce travail de thèse est consacré à l'étude de la susceptibilité vis-à-vis de la fragilisation par l'hydrogène de quatre aciers THLE : un DP, un TRIP, un CP et le BAS 100, un acier enrichi en vanadium et chrome. Un acier aux propriétés mécaniques plus modestes, dénommé HE (Haute Elasticité) a servi de référence. Les caractéristiques de transport de l'hydrogène dans ces aciers ont été étudiées, grâce à des essais de perméation électrochimique avec chargement en milieu acide, éventuellement additionné d'un promoteur d'hydrogénation (l'arsenic). Comme observé sur d'autres aciers, il faut souligner l'absence de conditions d'entrée stationnaires, dont il faut tenir compte dans l'évaluation des caractéristiques de diffusion. La diffusivité à température ambiante est apparue élevée pour tous les aciers, et une corrélation a été établie entre la microstructure et la diffusivité de l'hydrogène dans le matériau : plus la microstructure est fine et complexe, moins la diffusivité est élevée. De plus, l'évaluation des concentrations subsurfaciques sur les courbes en présence d'arsenic a révélé des valeurs relativement élevées pour les trois aciers aux caractéristiques mécaniques les plus élevées (TRIP 800, CP 800 et BAS 100). Ces valeurs sont conformes avec les teneurs en hydrogène diffusible mesurées par dosage juste après la perméation. Les dosages d'hydrogène résiduel, réalisés par désorption thermique sous vide après perméation, ont par ailleurs indiqué que le piégeage profond dans ces aciers était peu important, même après chargement sous polarisation et en présence d'arsenic. Ceci peut s'expliquer par des structures très bien élaborées, très fines et comportant peu de défauts. Des essais de traction ont montré qu'une hydrogénation sévère (en présence d'un promoteur) était nécessaire pour obtenir une fragilisation notable des aciers THLE. Hormis les cas extrêmes de dégradation spontanée par HIC (cloquage, fissuration), la fragilisation est imputable à l'hydrogène diffusible ou faiblement piégé car les teneurs en hydrogène piégé profondément restent négligeables. Dans les conditions industrielles, en décapage acide HCl en présence d'inhibiteurs, les résultats de perméation, de dosage et de traction s'accordent à montrer l'absence de fragilisation sur ce type d'acier. Les inhibiteurs testés semblent jouer un rôle de barrière physique, par adsorption sur le métal nu, limitant ainsi tant l'entrée d'hydrogène que la corrosion.

This thesis describes a novel "Tablet-in-a-Bottle" oral suspension formulation. Ingredients with unstable physical or chemical characteristics can be placed in a core tablet, and then dry compression coated with an outer layer which provides separation from other components. The new suspension formulation comprises fast disintegrating clavulanic acid (KCA) tablets with a powder mixture containing amoxicillin. Hardness, friability, flow properties and weight uniformity of tablets for three different formulations were investigated and were all improved in a third formulation. Stability tests under different humidities were conducted. Amoxicillin and clavulanic acid in the new formulations showed the same stabilities when compared with the marketed product Augmentin��. Preliminary pharmacokinetics and bioavailability of one new formulation were evaluated by comparing in vitro release rates and in vivo urinary excretion rates. In vitro dissolution studies were carried out according to the USP XXIII paddle method. The new formulation showed faster release rates during the first hour when stirring speed was 25 rpm. However, when 75 rpm stirring speed was applied, the dissolution profiles for the new formulation and the reference marketed product were identical. A randomized two-way crossover bioequivalence study was designed to evaluate the bioavailabilities. Cmax, Tmax and AUC[subscript o--->t] of amoxicillin were within ��20% of the reference pharmacokinetic values. However, Cmax and Tmax of clavulanate were not within ��20%. Bioeqivalence between this new suspension formulation and the marketed product (Augmentin��) were evaluated using a two one-sided t-test. There is not sufficient statistical support with this test to conclude that the two products are bioequivalent. However, this is most likely due to small sample size and high intersubject variation and statistical support for bioequivalence is expected in a larger study group. / Graduation date: 1998