Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Tobramycin disposition following airway administration was evaluated by meta-analysis of human data in the literature and, experimentally, using a realistic ex vivo model, the isolated perfused rat lung preparation (IPRL). Pulmonary bioavailability of inhaled tobramycin in published studies was re-evaluated separately for CF and healthy adults, with the drug’s intrinsic pharmacokinetic (PK) parameters obtained from intravenous (IV) studies in the literature. While large variations in tobramycin’s clearance precluded accurate assessment of its bioavailability, the results were indicative of substantial pulmonary absorption, in spite of its hydrophilic and poly cationic properties. To explore its disposition kinetics and mechanisms following airway administration, tobramycin absorption was investigated as a function of dose in the IPRL. The cumulative fraction of the administered tobramycin dose reaching the perfusate versus time, was bi-exponential and dose-dependent, unlike that of the marker solutes fluorescein and mannitol, both of which showed first-order and dose-independent kinetics. A kinetic model that incorporated lung tissue binding (or sequestration) alongside passive absorption was employed successfully to describe the aminoglycoside’s disposition in the IPRL following airway administration. Tobramycin’s absorption was fast with the first-order absorption rate constants (0.065-0.070 min-1) close to those seen with fluorescein (0.076 min-1), but a dose-, and concentration-dependent slow onset tissue binding prolonged its presence in the rat lung. Binding was confirmed by independent dynamic dialysis experiments using sliced lung prepared from the intact IPRL, immediately following airway administration using an identical technique as that used in tobramycin absorption studies. Dosing solution osmolality and pH had negligible effects on the drug’s disposition in the IPRL, when these were investigated over experimental ranges that could be used clinically. While tobramycin itself was found to accelerate mannitol’s absorption, and thus affect airway epithelial integrity when administered at high doses, the effect was undetectable at a dose level in rat lungs that was believed to produce airway concentrations corresponding to those in human patients using TOBI®. These findings may partly explain the apparent success of inhaled tobramycin therapy in the treatment of pulmonary infections.

R-(-)-Phenylephrine (PE) is the most commonly used nonprescription oral nasal decongestant in the United States. It is a selective α1-adrenergic receptor agonist and has many years of safe usage. However, the efficacy of PE is controversial, due to its extensive pre-systemic metabolism, which leads to low and variable oral bioavailability (38 ± 9%, mean ± SD). Sulfation plays a very important role in pre-systemic metabolism of PE. The sulfation of PE occurs at its phenolic group, which is the preferred structural feature of many sulfotransferase (SULT) substrates. Compounds with phenolic groups have similar structures to PE, which may share the same SULT isoforms with PE and have the potential to inhibit PE sulfation. Co-administration of the phenolic compounds from the Food and Drug Administration’s (FDA) “Generally Recognized as Safe” (GRAS) list, Everything Added to Food in the United States (EAFUS), or dietary supplements along with PE could be an effective strategy to inhibit the pre-systemic sulfation of PE. The primary side effect of PE is hypertension. Since monoamine oxidase (MAO) inhibitors may increase the risk of hypertension, they should not be taken with PE. In order to increase the oral bioavailability and eventually improve the efficacy of PE, this research project aimed to investigate the feasibility of inhibiting the pre-systemic sulfation of PE with phenolic dietary compounds. Considering the safety issue, this research project also aimed to investigate whether these phenolic dietary compounds have inhibitory effects on MAO-A/B. A human colon adenocarcinoma epithelial cell line (LS180), which shows sulfation activity, was used as a model to test the effect of these phenolic compounds on the sulfation of PE. The extent of disappearance of PE was significantly (p < 0.05) decreased to the following (mean ± SEM, as % of control) when incubated with phenolic dietary compounds in LS180 cells for 14 - 19 hrs: curcumin 24.5 ± 14.0%, guaiacol 51.3 ± 8.0%, isoeugenol 73.9 ± 4.3%, pterostilbene 70.6 ± 4.2%, resveratrol 14.2 ± 28.0%, zingerone 52.4 ± 14.6%, and the combinations eugenol + propylparaben 42.6 ± 8.4%, vanillin + propylparaben 37.0 ± 11.2%, eugenol + propylparaben + vanillin + ascorbic acid 31.1 ± 10.9%, eugenol + vanillin 57.5 ± 20.6%, and pterostilbene + zingerone 36.5 ± 7.0%. The combinations of curcumin + resveratrol and curcumin + pterostilbene + resveratrol + zingerone almost completely inhibited PE disappearance. PE sulfate formation was inhibited 67.0 ± 4.2% (mean ± SEM, as % of control) by guaiacol and 71.7 ± 2.6% by pterostilbene + zingerone. The combinations of curcumin + resveratrol and curcumin + pterostilbene + resveratrol + zingerone inhibited ≥ 99% of PE sulfate formation. These results were consistent with those from analysis of the disappearance of PE in LS180 cells. These phenolic inhibitors for sulfation were also tested to see whether they have any inhibitory effects on MAO-A or B. Significant inhibition was found with curcumin, guaiacol, isoeugenol, pterostilbene, resveratrol, and zingerone on both MAO-A and B. Further kinetic studies were conducted to investigate the concentration of an inhibitor at which the enzyme activity is reduced by half (IC50) (mean ± SEM) of these inhibitors. The most potent inhibitor for MAO-A was resveratrol (0.313 ± 0.008 μM) followed by isoeugenol (3.72 ± 0.20 μM), curcumin (12.9 ± 1.3 μM), pterostilbene (13.4 ± 1.5 μM), zingerone (16.3 ± 1.1 μM), and guaiacol (131 ± 6 μM). The most potent inhibitor for MAO-B was pterostilbene (0.138 ± 0.013 μM), followed by curcumin (6.30 ± 0.11 μM), resveratrol (15.8 ± 1.3 μM), isoeugenol (102 ± 5 μM), and guaiacol (322 ± 27 μM). Since these phenolic compounds all have relatively low oral bioavailability, any MAO inhibition which could occur systemically is expected to be limited. Most inhibitory effects on MAO-A and B if any would be limited to the GI tract and liver. In conclusion, several compounds and combinations showed inhibition on PE sulfation in LS180 cell model, which may have potential to inhibit the pre-systemic sulfation of PE to improve its oral bioavailability. These compounds also showed the unexpected inhibition on human MAO-A and B with different potency, which could guide the selection of phenolic dietary compounds for further studies, along with the sulfation inhibition results and their pharmacokinetic (PK) properties such as bioavailability.

Voies alimentaires d'amélioration de la biodisponibilité du fer et du zinc dans les aliments de complément consommés par les jeunes enfants en Ethiopie. Le retard de croissance et les carences en micronutriments sont largement répandus dans les pays en développement tels que l'Ethiopie et atteignent un pic pendant la période d'alimentation complémentaire. L'adéquation des pratiques d'alimentation complémentaire du jeune enfant a été évaluée par rappel de 24h auprès de 76 ménages dans la région nord du Wollo, au nord de l'Ethiopie. Plusieurs pratiques d'alimentation n'étaient pas en accord avec les recommandations internationales WHO/PAHO. Les aliments les plus fréquemment consommés étaient l'injera –une sorte de galette à base de céréales fermentées- accompagnée de sauces à base de légumineuses, et le pain. Les procédés de transformation traditionnels de ces aliments ont été observés sur le terrain. Différents mélanges de céréales étaient utilisés pour la préparation de l'injera. Le type de mélange conditionne la cinétique de fermentation, qui à son tour, affecte l'hydrolyse de l'acide phytique. Même lorsque la dégradation de l'acide phytique était supérieure à 95%, la bioaccessibilité du fer et le pourcentage d'absorption calculé par algorithme n'étaient pas améliorés, alors que les ratios molaires phytate:Fe étaient optimaux (<0.4). D'autres inhibiteurs d'absorption semblent jouer un rôle important. A cet égard, les effets relatifs des phytates, polyphénols et fibres sur la bioaccessibilité du fer ont été évalués par une approche mécanistique utilisant des enzymes exogènes. Dans les farines utilisées pour la préparation de l'injera, la déphytinisation suivie de l'hydrolyse des fibres et/ou l'oxydation des polyphénols permet une augmentation de la bioaccessibilité du fer plus importante que la seule déphytinisation. La réponse aux traitements enzymatiques ainsi que l'importance relative des différents inhibiteurs d'absorption étaient dépendantes de la matrice alimentaire. L'optimisation des procédés traditionnels de transformation en vue de favoriser la dégradation des phytates, des polyphénols chélateurs de fer et des fibres pourrait améliorer significativement la biodisponibilité du fer dans les injeras. Des interventions visant à promouvoir les bonnes pratiques d'alimentation complémentaires recommandées par l'OMS sont nécessaires dans les régions enquêtées. Mots-clés: Phytate, polyphénols, fibres, altitude, micronutriments, bioaccessibilité / Food-based strategies to enhance iron and zinc bioavailability of complementary foods consumed by young children in EthiopiaStunting and micronutrient deficiencies are widespread in developing countries like Ethiopia and reach their peak during the period of complementary feeding. The adequacy of complementary feeding practices of young children in north Wollo, northern Ethiopia was evaluated in 76 households using two 24h recalls. Several feeding practices were not in accordance with WHO/PAHO recommendations. The most frequently consumed foods were legume-based stews, bread, and injera- a fermented cereal-based pancake. Traditional processing of these foods was observed in-field. Different cereal blends were used in injera preparation and this influenced the fermentation kinetics which in turn affected phytic acid hydrolysis. Even when phytic acid degradation was >95%, iron bioaccessibility and algorithm predicted absorption were not improved, despite ideal phytate:Fe molar ratios (<0.4). This suggested an important role of other absorption inhibitors. In this regard, the relative effect of phytate, polyphenols, and fibers on iron bioaccessibility was evaluated by making use of a mechanistic approach that involved the application of exogenous enzymes. In injera flours, dephytinization followed by hydrolysis of fibers and, or oxidation of polyphenols, resulted in higher iron bioaccessibility than dephytinization alone. The relative importance of mineral absorption inhibitors as well as the response to enzymatic treatments was dependent on the food matrix. If possible, optimization of household food processing for greater decrease in phytate, iron-binding polyphenols and fibers may be needed to significantly improve iron bioavailability in injeras. Interventions promoting the WHO guiding principles for complementary feeding practices and behaviors are recommended. Keywords: Phytate, polyphenols, fibers, altitude, micronutrients, bioaccessibility

Le cycle biogéochimique des métaux traces a été fortement accéléré par les activités anthropiques qui ont entraîné une contamination des eaux et des sédiments des rivières. A la suite de leurs émissions, la majorité des métaux traces se trouvent sous forme particulaire qui se transportent par ruissellement et se retrouvent en milieu fluvial où elles sédimentent et dont une partie est susceptible d'être solubilisée vers la colonne d'eau suite aux modifications des conditions physico-chimiques du milieu et sous l'action des microorganismes autochtones et pouvant après interagir avec la chaîne alimentaire et présenter un danger potentiel de toxicité pour l'homme et pour les autres organismes vivants. Dans cette étude, nous avons choisit de travailler sur le site de la rivière Al-Ghadir qui présente un cas exceptionnel et original des pollutions où la hauteur de sédiments, comprenant plusieurs types de polluants, est plus qu'un mètre. L'objectif de cette thèse était de comprendre et d'évaluer le rôle du compartiment microbien dans les sédiments de la rivière Al-Ghadir, qui est la source la plus polluante de la méditerranéen, sur la mobilité des métaux et leurs effets sur les eaux souterraines. Cette étude était réalisée en deux séries d'expériences (Batch et colonne du sol) semblables aux situations se trouvant dans la rivière. Une caractérisation physico-chimique et chimique des sites d'étude a été effectuée comme première étape afin ensuite de débuter l'approche expérimentale qui a permis d'isoler les processus physico-chimiques de ceux qui sont imputables à l'activité microbiologique. Dans les expériences menées en réacteurs fermés (batchs), nous avons montré que les activités microbiennes sont corrélées aux fortes dissolutions des métaux, en particulier du Fe, Mn, Pb, Cu et Zn. Le fer semble apparaître comme l'élément le plus solubilisé et sa solubilisation était corrélée à celle d'autres métaux traces laissant supposer que ces métaux sont associés aux oxydes de fer. Cette hypothèse a été confirmée par les extractions séquentielles indiquant la présence de bactéries ferri-réductrices qui, lors de la fermentation du glucose et la production d'acides organiques, ont réduit les oxydes de fer. Ces derniers ont entraîné la dissolution des métaux traces et une modification des populations bactériennes qui ont été détectés par l'étude microbiologique et génétique après cinq jours d'incubation. L'effet des bactéries sur la mobilisation des métaux a été ensuite étudié selon des expériences portant sur l'étude hydrodynamique du transfert des métaux en colonnes de sédiments et dans des conditions proches à celles du terrain. Nous avons montré que (i): les métaux étudiés ne sont pas lixiviés dans les mêmes ordres et en règle générale montrent l'ordre suivant (en μg/l): Fe>Mn>Cd>Zn>Cu>Pb≥Cr ; (ii) les métaux vont se reprécipiter sur les phases néoformées après que le système regagne l'équilibre. Les études du profil de distribution des métaux dans les colonnes ont mis en évidence que les métaux ont été lixiviés des sédiments durant l'incubation de façon homogène. Cette répartition dépend de la hauteur du sédiment: la ré-distribution est maximale à la surface des sédiments (0-10 cm), alors qu'à une profondeur située entre 10 et 25 cm elle est nulle. Ce phénomène est expliqué par le fait que les métaux après avoir été solubilisés et passés en solution, ils seraient réadsorbés sur les phases électrochimiques négatives, néoformées et colloïdales ce qui explique la diminution de la concentration des métaux dans le lixiviat obtenu en laboratoire et permet de penser que ce mécanisme de piégeage des métaux dans la colonne limite la migration de ces derniers vers les eaux souterraines, tant que la capacité d'adsorption des colloïdes présents n'est pas atteinte et que le système soit en équilibre / The biogeochemical cycle of trace metals was greatly accelerated by human activities that have led to the contamination of water and river sediments. Following their emissions, the majority of trace metals exist in particulate form which can be transported by runoff and end up in rivers where they settle and where a portion can be dissolved into the water column in response to changes in the physico-chemical conditions of the site and under the action of indigenous microorganisms which later can interact with the food chain and pose a potential danger of toxicity to humans and other living organisms. In this study, we have chosen to work on Al-Ghadir River which represents an exceptional and an original case of pollution where the height of sediments, including several types of pollutants, is more than one meter. The aim of this work was to understand and to evaluate the role of the microbial compartment in the sediments of the Al-Ghadir River, which is the most polluting source to the Mediterranean, on the mobility of metals and their effects on underground water. This study was realized in two series of experiments (batch and soil column) with situations similar to those found in the river. A physico-chemical and chemical characterization of the studied sites was conducted as a first step to begin, after that, with the experimental approach which was used to isolate the physico-chemical processes from those which are attributable to microbiological activity. In the experiments conducted in closed reactors (batch), results obtained showed that the microbial activities are correlated with the strong dissolution of metals, especially for Fe, Mn, Pb, Cu and Zn. Iron appeared the most solubilized element and its solubilisation was correlated with the other trace metals suggesting that these metals are associated to iron oxides. This hypothesis was confirmed by sequential extraction procedure indicating the presence of iron-reducing bacteria, which, during the fermentation of glucose and the production of organic acids, reduced iron oxides. These later have led to the dissolution of trace metals and to a change in the bacterial populations which were detected after five days of incubation by the microbiological and the genetic studies. The effect of the bacteria on the mobilization of metals in sediments was then studied in hydrodynamic columns, under conditions similar to those in the field. Results obtained showed that: (i) Studied metals are not leached in the same order and showed the following order (in μg/l): Fe > Mn > Cd > Zn > Cu > Pb ≥ Cr; (ii) Metals will reprecipitate on the neoformed phases after the system returns to equilibrium. Studies of the distribution profile of metals in columns showed that metals were leached homogenously from the sediments during incubation. This distribution was shown to depend on the height of the sediment where the re-distribution was shown at its maximum at the surface of the column sediments (0-10 cm) and became null at a depth between 10 and 25 cm. This phenomenon is explained by the fact that the metals after being dissolved and passed into solution, were then readsorbed to the negative electrochemical, neoformed and colloidal sediment phases which explains the decrease in the concentration of metals in the leachate obtained in the laboratory and suggests that the mechanism of trapping of metals in the column limits the migration of these later to underground water, as the adsorption capacity of present colloïds is not reached and the system is at equilibrium

Master of Science / Department of Food, Nutrition, Dietetics, and Health / Brian L. Lindshield / Fortified-blended foods (FBFs), grain-legume porridges (most commonly corn and soy), are frequently used for food aid purposes. Sorghum and cowpea have been suggested as alternative FBF commodities because they are drought-tolerant, grown locally in food aid receiving countries, and are not genetically modified. The objective of this thesis was to determine the protein quality and iron bioavailability of newly formulated, extruded FBFs in broiler chickens, which have been suggested as a good model for assessing iron bioavailability. Five FBFs were formulated to contain whey or soy protein to compare protein quality, sugar, oil, and an improved micronutrient premix. These included three white sorghum-cowpea FBFs; two were extruded with either whey protein concentrate (WSC) or soy protein isolate (WSC+SPI) added, one was non-extruded (N-WSC). Two others were white sorghum-soy (WSS) and corn-soy (CSB14) FBFs. Two additional white-sorghum cowpea FBFs were reformulated and “over-processed” to contain no sugar, less whey (O-WSC) or soy protein (O-WSC+SPI), and less oil, thus producing a less expensive FBF. Two studies were performed using prepared (Prep) or dry (Dry) FBFs, along with the United States Agency for International Development (USAID) corn and soy blend FBF, CSB+, fed to chickens for 3 and 2 weeks, respectively; food intake, body weights, hemoglobin, and hepatic iron were assessed. In the Prep study, new FBFs significantly increased caloric and protein efficiency compared to CSB+, despite similar food intake and body weight gain. In the Dry study, CSB+ significantly decreased food intake and caloric efficiency, with the exception of O-WSC+SPI, and nonsignificantly reduced body weight gain and protein efficiency compared to new FBFs. CSB+ significantly reduced hepatic iron content compared to all FBFs in the Dry study, and was nonsignificantly decreased compared to new FBFs in the Prep study. In conclusion, sorghum and cowpea FBFs performed similarly to corn and soy FBFs, suggesting these commodities are suitable replacements for corn and soy. Soy protein isolate (WSC+SPI) was an effective alternative to whey protein concentrate (WSC), suggesting SPI can be a less expensive protein supplement in FBFs. Surprisingly, non-extruded sorghum and cowpea (N-WSC) was equally efficacious to extruded WSC. However, N-WSC did not meet viscosity requirements and is not precooked, which limits its viability as an FBF. O-WSC+SPI resulted in poorer outcomes compared to other FBFs, which suggests the protein quality of cowpea may be inferior and the inclusion of whey protein is needed in this formulation, as O-WSC with whey performed similarly to other FBFs. Overall, new FBFs, with the exception of O-WSC+SPI, resulted in improved food efficiency and hepatic iron outcomes compared to CSB+, suggesting they are of higher nutritional quality. However, further research is needed to refine and identify the best FBF formulations.

Dans le contexte du traitement du kératocône, une formulation contenant de la riboflavine, un principe actif hydrosoluble, deux tensio-actifs (le poloxamère 407 et la monooléine) et de l'eau a été préparée par un processus d'homogénéisation. Un plan factoriel fractionnaire a été utilisé pour estimer les effets principaux et les interactions de cinq paramètres sur deux réponses pertinentes, à savoir la taille des particules et l'efficacité d'encapsulation. Les cinq paramètres étudiés étaient la température des deux phases, la durée de l'émulsification, la présence du chauffage pendant l'homogénéisation, le nombre de cycles et la pression. Il a ainsi été montré que les paramètres les plus influents sont la présence du chauffage pendant l'homogénéisation et la pression qui ont conduit à l'obtention de nanoparticules d'une taille moyenne de 145 nm et une efficacité d'encapsulation moyenne de 46%. La détermination des paramètres optimaux du procédé de fabrication a conduit à l'optimisation de la formulation par le biais de plans d'expériences. L'influence combinée de trois composants a été étudiée dans une partie du diagramme de phase. Ainsi, douze formules décrivant l'espace de conception ont été préparées. Les résultats obtenus par diffraction des rayons X aux petits angles et par cryo-microscopie électronique en transmission ont mis en évidence la présence de nano-objets de structure éponge et/ou hexagonale inverse. Le pourcentage de chacun des composants a été déterminé pour obtenir à la fois une grande efficacité d'encapsulation et une petite taille de particules. Deux formulations très proches dans le diagramme de phase ternaire, ont répondu à ces exigences. / In the context of the keratoconus treatment, a formulation containing riboflavin a water-soluble drug, two surfactants (poloxamer 407 and mono acyl glycerol) and water was optimized and prepared by emulsification and a homogenization process. A fractional factorial design was applied to estimate the main effects and interaction effects of five parameters on two relevant responses, namely particle size and encapsulation efficiency. The five parameters studied were the temperature of the two phases, the duration of emulsification, the presence of heating during homogenization, the number of passes and pressure. It has been shown that the most influent parameters are the presence of heating during the homogenization and the pressure that led to the production of nanoparticles with an average size of 145 nm and an average encapsulation efficiency of 46 %. The determination of the optimal parameters of the process led to an optimization of the formulation by using experimental design. The combined influence of three factor variables (or components) of the formulation that are water, monoolein and poloxamer 407 were, studied. In this way, twelve formulas describing the design space were prepared. Results obtained using SAXS and cryo-TEM evidenced the presence of nano-objects with either sponge or hexagonal inverted structure. In the zone of interest, the percentage of each component was determined to obtain both high encapsulation efficiency and small size of particles. Two formulations are very close in the ternary phase diagram, and have responded to these requirements.

Complex medication regimens have major implications on patient therapy. When we consider that these regimen therapies can also be further convoluted by co-morbidity, it is then seen as an essential opportunity to research possible solutions to alleviate such complications. Globally identified conditions such as the Human Immuno-deficiency Virus (HIV) and Tuberculosis (TB) are known to have such complications within their respective regimens. In many cases, the regimental therapies themselves are overbearing with high pill burdens having to be taken in segregated manners throughout the day. Within a standard TB regimen, isoniazid and rifampicin are seen to have a deleterious drug-drug interaction in which the bioavailability is compromised through formation of an insoluble complex. Despite this interaction, the 2 active drugs must be taken concurrently for successful TB therapy. No true solution exists as fixed dose combinations of isoniazid and rifampicin (Rifinah®) are still in production despite the detrimental interaction that impedes successful bioavailability. The once daily multi-unit drug delivery system (ODMUS) has the benefits of superseding the described problems and aiding in therapeutic outcomes. Preliminary studies utilized preliminary testing to ascertain the science surrounding the 2 components of the ODMUS, the memblet and the multiparticulate components. pH-sensitive polymers (Eudragit® L100-55 and E 100) were of critical importance to the success of the system and were individually manipulated for each component to produce a novel memblet and multiparticulate system through a unique salting out approach. Primary studies focused on drug release testing and drug entrapment for the multiparticulate component. Testing of the memblet system addressed dissolution and thermal analysis. Utilizing this data, a series of process variables were used to achieve an optimized formulation through a Box- Behnken statistical design. Optimized formulations used response testing to establish the optimal characteristics of both components. Multiparticulates achieved controlled release for 12 hours with an enhanced 71% drug entrapment efficiency. Memblet release profiles were confirmed over 2 hours with a maximal Tg of 56°C. Molecular modeling corroborated release understanding for both components. Surface area and porosity analysis, surface morphology, fourier transform infrared spectroscopy as well as thermal, rheological and mechanical analysis were additional tests undertaken on the optimized formulations. In vivo analysis was the final testing to verify validity of the ODMUS components and utilized a pig model for the investigation. UPLC blood analysis revealed increase blood levels of INH (CmaxINH= 0.0138ng/mL) and RIF (CmaxRIF= 0.052ng/mL) in relation to conventional dosage forms validating segregated site-specific release and increased bioavailability. Ideally, a segregated means of drug delivery throughout the gastrointestinal tract was achieved such that an enhanced bioavailability, a more controlled release and a simplified medication regimen was produced. This study aimed to achieve said goals through novel technique analysis, innovation and globally approved science to critically assess the success of the ODMUS as a potential means to reduce the complexities of medication regimen therapy.

A biodisponibilidade é o fator determinante da eficácia clínica de um fármaco e depende diretamente das propriedades de solubilidade e permeabilidade da substância ativa. O Sistema de Classificação Biofarmacêutica (SCB), baseado nestas características, consolidou-se nos últimos anos como ferramenta de auxílio na predição da biodisponibilidade de fármacos. O SCB tem sido empregado no desenvolvimento de formas farmacêuticas, contendo novos fármacos ou não, e no registro de medicamentos genéricos, por conta das limitações técnicas, econômicas e éticas para a realização dos ensaios diretos de biodisponibilidade. Assim, a avaliação das propriedades de solubilidade e permeabilidade dos fármacos, embora indiretamente, oferece objetivas indicações sobre a eficácia dos medicamentos, com vantagem de consolidar modelos in vitro, mais facilmente reprodutíveis, sem trazer riscos a voluntários sadios. Dentre os estudos de solubilidade destaca-se o método do equilíbrio que emprega a técnica de shake-flask. Para a determinação da permeabilidade in vitro, diferentes técnicas têm sido empregadas, dentre as quais destacam-se modelos que empregam tecido intestinal de animais. O presente trabalho teve como objetivos a avaliação da solubilidade e da permeabilidade de fármacos antirretrovirais (lamivudina e zidovudina) e o desenvolvimento de protocolo para determinação da permeabilidade em segmentos de intestino de ratos, por meio de modelo in vitro em ensaios com células de Franz. A solubilidade dos fármacos propostos foi caracterizada pela técnica shake-flask e por meio da dissolução intrínseca, sendo que os resultados permitiram concluir que, segundo o SCB, os fármacos zidovudina e lamivudina apresentam alta solubilidade. Os ensaios de permeabilidade demonstram que o método proposto é viável e os valores de permeabilidade da lamivudina e da zidovudina sugerem que ambos os fármacos podem ser classificados como de alta permeabilidade. / Bioavailability is the determinant of the clinical efficacy of a drug and is directly dependent on the properties of solubility and permeability of the active substance. The Biopharmaceutical Classification System (BCS), based on these characteristics, has become in recent years as a tool to aid in predicting the bioavailability of drugs. The BCS has been used in the development of dosage forms, containing new drugs or not, and the registration of generic drugs, since there are technical limitations, economic and ethical guidelines for the testing of direct bioavailability. Thus, the evaluation of the solubility and permeability of the drugs, although indirectly, provides objective indications on the effectiveness of medicines, with the advantages of consolidating in vitro models more easily reproducible without bringing risk to healthy volunteers. Among the solubility studies highlight the shake-flask method, recommended by regulatory agencies. To determine the in vitro permeability, different techniques have been employed, among which stand out models based on intestinal tissue obtained from different animals. This study aims to evaluate the solubility and permeability of antiretroviral drugs (lamivudine and zidovudine), and the development of protocol for the determination of permeability in intestine segments of rats using in vitro model in experimental Franz cells. So far, the solubility of proposed drugs was characterized by shake-flask method and through the intrinsic dissolution. About the solubility, results showed that, according to BCS, the drugs zidovudine and lamivudine has high solubility. About the intrinsic dissolution, results showed agreement with the results of the solubility. Permeability tests showed that the proposed method is feasible and the permeability values of lamivudine and zidovudine suggest that both drugs can be classified as high permeability.

Introdução: A deficiência de ferro é frequente entre mulheres na idade reprodutiva e é considerada problema de saúde pública mundial. Por outro lado, patologias associadas com aumentada atividade eritropoética e sobrecarga de ferro, como as talassemias e a anemia falciforme, estão entre as doenças monogênicas mais frequentes em muitas populações. Os genes HFE e TMPRSS6 codificam as proteínas hemocromatose hereditária (HFE) e matriptase-2 (MT2) que, no fígado, modulam a produção de hepcidina, o hormônio regulador central do metabolismo de ferro. O objetivo deste estudo foi avaliar a relação entre o consumo alimentar de ferro, as variantes rs855791 (MT2736V), rs4820268 (MT2521V), rs1799945 (HFE63D) e rs1800562 (HFE282Y) e o status corporal do mineral entre mulheres com atividade eritropoética normal (aparentemente saudáveis) ou levemente aumentada (com &#946;-talassemia menor). Casuística e métodos: Inicialmente, foram incluídas 127 estudantes universitárias na idade reprodutiva (18 a 42 anos) e em aparente balanço estacionário do ferro corporal (necessidades fisiológicas e consumo alimentar de ferro pouco variáveis há pelo menos 12 meses). Em um segundo estudo, foram incluídos 33 casos de &#946;-talassemia menor (18 na pós-menopausa), registrados em serviços de hematologia de dois hospitais de São Paulo-SP e um de Sorocaba-SP. Essas foram pareadas com 66 controles, segundo idade, índice de massa corporal, status reprodutivo e uso de anticoncepcionais hormonais. A partir de inquéritos feitos com registros alimentares ou recordatórios de 24 horas foi estimado o consumo de ferro total e biodisponível. Amostras de sangue foram utilizadas para a extração de DNA e determinações de ferritina sérica, saturação da transferrina e hemoglobina. As genotipagens do TMPRSS6 e do HFE foram realizadas por PCR em tempo real. Resultados: Considerando as 226 mulheres avaliadas, as frequências dos alelos MT2736V, MT2521D, HFE63D e HFE282Y foram estimadas em 40,3%, 44,0%, 16,3% e 1,5% respectivamente. No primeiro estudo, foi estimada média de consumo de ferro 10 de 10,9 mg/dia e prevalência de deficiência do mineral de 12,6%. Estimativas de consumo de ferro biodisponível, mas não de ferro total, foram correlacionadas com os valores de ferritina e saturação da transferrina. As associações entre a biodisponibilidade dietética de ferro e seus biomarcadores foram especialmente evidentes entre as carreadoras da variante HFE63D, indicando uma significante interação gene-nutriente. Por outro lado, valores relativamente menores de saturação da transferrina foram associados à presença do alelo MT2736V, independentemente do consumo de ferro biodisponível. Mulheres com &#946;-talassemia menor e suas controles não diferiram quanto à frequência das variantes TMPRSS6 e HFE ou à biodisponibilidade dietética de ferro. Na pós-menopausa, a &#946;-talassemia menor foi associada com valores duas vezes maiores de ferritina, 20% maiores de saturação da transferrina e com probabilidade 3,5 vezes maior de hiperferritinemia. Entretanto, para casos e controles na idade reprodutiva, foi estimada probabilidade de inadequação do consumo de 20,7% e prevalências de deficiência do mineral de 13,3% e 10,0%, respectivamente. Entre essas mulheres, o genótipo positivo ou negativo para a variante MT2736V foi também associado com diferenças nas médias de saturação da transferrina. No entanto, o contraste nesses valores foi relativamente maior entre as mulheres com &#946;-talassemia menor. Além disso, mais acentuada hipocromia acompanhou a presença da variante MT2736V nessa condição. Conclusão: Os achados sugerem que, entre mulheres com eritropoese normal ou com &#946;-talassemia menor, a variante MT2736V não afeta tão fortemente as reservas de ferro corporal como faz a adequação do consumo desse mineral. Ainda assim, a variante HFE63D pode modificar a relação da biodisponibilidade de ferro com seu status corporal e, portanto, ser um importante marcador preditivo de resposta diferencial à dieta. A variante MT2736V foi associada com menor disponibilidade de ferro na circulação de mulheres na idade reprodutiva e, entre aquelas com &#946.;-talassemia menor, com indício de acentuada alteração morfológica dos eritrócitos. / Introduction: Iron deficiency is common among women at childbearing age and it is regarded as a worldwide public health issue. On the other hand, disorders associated with increased erythropoietic activity and iron overload, such as thalassemias and sickle cell disease, are among the most frequent Mendelian diseases in many populations. HFE and TMPRSS6 genes encode the hereditary hemochromatosis protein (HFE) and the matriptase-2 (MT2) both of which modulate the hepatic production of hepcidin, the main hormone regulator of iron metabolism. The aim of this study was to evaluate the relationship among dietary iron intake, rs855791 (MT2736V), rs4820268 (MT2521D), rs1799945 (HFE63D) and rs1800562 (HFE282Y) genetic variants and body iron status of women with normal (apparently healthy) or slightly increased (&#946;-thalassemia minor) erythropoietic activity. Casuistic and methods: Initially, 127 university students at childbearing age (18 to 42 years old) and with steady state body iron (few variations on physiological requirements and dietary iron intake at least for the last 12 months) were included. In a second study, it was included 33 cases of &#946;-thalassemia minor (18 of them post-menopaused) registered in Hematology Services from two hospitals from São Paulo-SP and one from Sorocaba-SP. They were paired with 66 controls by age, body mass index, reproductive status and hormonal contraceptive use. Using food diaries or 24 hours food recalls, total and bioavailable dietary iron intakes were estimated. Blood samples were used for DNA extraction and for determinations of ferritin, transferrin saturation with iron and hemoglobin. TMPRSS6 and HFE genotyping were performed by real time PCR. Results: Considering all the 226 women studied, the allelic frequencies of MT2736V, MT2521D, HFE63D e HFE282Y genetic variants were em 40.3%, 44.0%, 16.3% e 1.5%, respectively. In the first study, a total dietary iron intake of 10.9 mg/day and an iron deficiency prevalence of 12.6% were estimated. There were correlations among ferritin and transferrin saturation values with estimates of bioavailable, but not of total dietary iron intake s. Associations between dietary iron bioavailability and iron biomarkers were especially evident among carriers of HFE63D variant, indicating a significant gene-diet interaction. On the other hand, lower levels of transferrin saturation were associated with the presence of MT2736V variant allele, irrespective of bioavailable iron intake. TMPRSS6 and HFE variants frequencies and dietary iron bioavailability estimates did not differ between women with &#946;-thalassemia minor and their controls. Among postmenopausal women, &#946;-thalassemia minor was associated with two times higher ferritin values, 20% higher transferrin saturation values and 3.5 times higher chance for hiperferritinemia. However, among cases and controls at childbearing age, it was estimated a probability of inadequacy in the dietary iron intake of 20.7% and iron deficiency prevalences of 13.3% and 10.0%, respectively. Among these women, a positive or negative genotype for MT2736V was also associated with differences in transferrin saturation. Nevertheless, the contrast between these values was relatively higher among women with &#946;-thalassemia minor. Moreover, a more accentuated hypochromia accompanied the presence of the MT2736V variant in this condition. Conclusions: Our findings suggest that, among women with normal erythropoiesis or &#946;-thalassemia minor, the presence of the MT2736V variant does not strongly impact the body iron stores as does dietary iron adequacy. Nevertheless, the HFE63D variant may modify the relationship between the dietary iron bioavailability and the body iron status. Therefore, it might be an important predictive marker of women\'s differential response to diet. The MT2736V variant was associated with lower availability of circulating iron in women at childbearing age and, among those with &#946;-thalassemia minor, with suggestive accentuated morphological alteration of erythrocytes.