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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
451

Determinação da bioequivalência do metronidazol a partir de comprimidos revestidos / Bioequivalence determination of metronidazole from coated tablets

Silva, Marina de Freitas 20 August 2009 (has links)
O metronidazol é usado no tratamento de infecções causadas por protozoários e naquelas causadas por microrganismos anaeróbicos, no tratamento das formas intestinais e extra-intestinais de amebíase, em tricomoníase e em infecções bacterianas aeróbicas graves. Após administração oral, a absorção é rápida e completa sendo amplamente distribuído, atinge concentração plasmática máxima em 1-2 horas. A meia-vida de eliminação do metronidazol é de 6-12 horas. O objetivo deste trabalho foi avaliar a equivalência terapêutica por meio da bioequivalêmcia entre duas formulações de comprimidos revestidos contendo metronidazol, produzidos por dois fabricantes distintos, permitindo assim a intercambiabilidade entre as formulações. O ensaio de bioequivalência entre o produto teste (FUNED metronidazol) e o produto referência (Flagyl® - Aventis Pharma Ltda.) foi do tipo randomizado, cruzado e aberto. O medicamento foi administrado em dose única de 250 mg de metronidazol aos 24 voluntários sadios. Amostras de sangue foram coletadas até 48 horas após a administração e analisadas por método, desenvolvido e validado, de cromatografia líquida de alta eficiência acoplada à espectrometria de massas (CLAE- MS/MS). As curvas de decaimento plasmático obtidas para o produto teste (FUNED metronidazol) e para o produto referência (Flagyl® - Aventis Pharma Ltda.) foram semelhantes, assim como os parâmetros farmacocinéticos Cmax (teste: 6,66 µg/mL; referência: 6,77 µg/mL), tmax (teste: 1,26 h; referência: 1,90 h), ASC0-t (teste: 73,42 µgxh/mL; referência: 73,56 µgxh/mL), ASC0-∞ (teste: 75,15 µgxh/mL; referência: 75,23 µgxh/mL) e t½el (teste: 8,00 h; referência: 7,76 h). Os intervalos de confiança 90% para a razão de Cmax (92,2 - 106,4 %), ASC0-t (97,2 - 102,5 %) e ASC0-∞ (97,1 - 102,8 %) encontram-se entre 80 e 125 %, intervalo proposto pela ANVISA e FDA para a bioequivalência. A comparação estatística por meio de análise de variância (ANOVA) dos parâmetros Cmax, ASC0-t e ASC0-∞ indica claramente não haver diferença significativa entre os dois produtos contendo 250 mg de metronidazol. Baseado nos resultados farmacocinéticos e estatísticos, conclui-se que os dois produtos são bioequivalentes e, podem ser considerados intercambiáveis na terapêutica. / Metronidazole is used to treat infections caused by protozoa and those caused by anaerobic microorganisms. It is the drug of choice for the treatment of amebiasis in the intestinal and extra-intestinal forms, trichomoniasis and bacterial aerobic diseases. After oral administration, its absorption is rapid, complete and widely distributed, reaching maximum plasma concentration in 1 to 2 hours. The half-life of elimination of metronidazole is 6 to 12 hours. The objective of this study was to evaluate the therapeutic equivalence through bioavalability between two formulations of tablets containing metronidazole, produced by two different manufacturers, thus allowing the interchangeability between the formulations. The bioequivalence assay between the test product (FUNED Metronidazole) and reference product (Flagyl® - Aventis Pharma Ltda.) was a randomized, crossover and open study. The drug was given at a 250 mg metronidazole single dose to 24 healthy volunteers. Blood samples were collected until 48 hours after administration and analyzed by method, developed and validated in high performance liquid chromatography coupled to mass spectrometry (HPLC - MS / MS). The plasma decay curves obtained for the product test (FUNED metronidazole) and the reference product (Flagyl® - Aventis Pharma Ltda.) were statistically similar in the same way as the pharmacokinetic parameters Cmax (test: 6.66 µg/mL, reference: 6.77 µg/mL), tmax (test: 1.26 h; reference: 1.90 h), AUC0-t (test: 73.42 µgxh/mL, reference: 73.56 µgxh/mL) AUC0-∞ (test: 75.15 µgxh/mL, reference: 75.23). The 90% confidence intervals for the ratio of Cmax (92.2 - 106.4%), AUC0-t (97.2 - 102.5%) and AUC0-∞ (97.1 - 102.8%) are between 80 and 125%, range proposed by ANVISA and FDA for bioequivalence assays. This statistical parameters comparison using analysis of variance (ANOVA) Cmax, AUC0-t and AUC0-∞ clearly indicate no significant difference between the two products containing 250 mg of metronidazole. Based on the pharmacokinetic and statistical results, it is possible to conclude that the two products are bioequivalent and could be considered interchangeable in therapy.
452

Influência do diabetes descompensado na disposição cinética, metabolismo e farmacocinética-farmacodinâmica dos enantiômeros do tramadol em pacientes com dor neuropática / Influence of uncontrolled type 1 and type 2 diabetes on the kinetic disposition, metabolism and pharmacokinetics-pharmacodynamics of tramadol enantiomers in patients with neuropathic pain

Moraes, Natalia Valadares de 30 November 2011 (has links)
O tramadol é um analgésico de ação central eficaz na atenuação de dores agudas e crônicas, entre elas a dor neuropática em pacientes diabéticos. Encontra-se disponível na clínica como mistura de (+)-tramadol e (-)-tramadol. O tramadol é metabolizado pelo CYP2D6 em O-desmetiltramadol (M1) e pelo CYP3A4 e CYP2B6 em N-desmetiltramadol (M2). Ambos enantiômeros do tramadol e o (+)-M1 contribuem para a atividade analgésica: o (+)-tramadol e o (+)-M1 agem como agonistas do receptor -opióide; o (+)-tramadol inibe a recaptação de serotonina; e o (-)-tramadol inibe a recaptação de noradrenalina. O estudo investiga a influência do diabetes mellitus (DM) tipo 1 e tipo 2 descompensados na disposição cinética, metabolismo e farmacocinética-farmacodinâmica dos enantiômeros tramadol em pacientes com dor neuropática. Os pacientes não diabéticos (Grupo Controle, n=12), os pacientes com DM tipo 1 (n=9) e os pacientes com DM tipo 2 (n=9), todos portadores de dor neuropática e fenotipados como metabolizadores extensivos do CYP2D6, receberam dose única oral de 100 mg de tramadol racêmico. Amostras seriadas de sangue foram coletadas até 24 h após a administração do tramadol para o estudo farmacocinético e para a avaliação das concentrações de noradrenalina. A dor dos pacientes foi avaliada através da escala analógica visual de dor nos mesmos tempos de coleta de sangue. Os pacientes foram avaliados quanto à atividade in vivo do CYP3A utilizando midazolam como fármaco marcador e genotipados para o CYP2B6. As concentrações plasmáticas total e livre dos enantiômeros do tramadol, M1 e M2 foram analisadas por LC-MS/MS usando a coluna Chiralpak® AD. A disposição cinética do tramadol é enantiosseletiva nos pacientes dos Grupos Controle e DM tipo 1, com acúmulo plasmático do (+)-tramadol. O DM tipo 1, mas não o DM tipo 2, reduz a AUC do metabólito ativo (+)-M1 e simultaneamente aumenta sua fração livre. Portanto, a concentração plasmática livre do eutômero (+)-M1 permanece inalterada nos pacientes portadores de DM tipo 1 e DM tipo 2. Não foram observadas diferenças entre os Grupos Controle, DM tipo 1 e DM tipo 2 quanto às razões metabólicas plasmáticas e urinárias do metoprolol/-hidroximetoprolol e quanto ao clearance do midazolam. Correlações significativas entre as razões metabólicas de AUC (+)-tramadol/(+)-M1 ou (-)-tramadol/(-)-M1 e a atividade in vivo do CYP2D6 avaliada em plasma ou urina empregando o metoprolol como fármaco marcador sugerem a aplicação do tramadol como fármaco marcador do CYP2D6. Os dados também mostram uma tendência de aumento do clearance do (+)-tramadol e do (-)-tramadol em virtude da presença do alelo mutante T no polimorfismo 516G>T do CYP2B6. O modelo sigmóide de efeito máximo fracional foi empregado para descrever a relação farmacocinética-farmacodinâmica do tramadol em pacientes com dor neuropática, relacionando as concentrações plasmáticas livre do (+)-M1 com o efeito analgésico do tramadol. O presente estudo mostra a importância da análise da concentração livre dos enantiômeros individuais do tramadol e seus metabólitos nos estudos de farmacocinética-farmacodinâmica. / Tramadol is a centrally acting analgesic that effectively relieves acute and chronic pain, including neuropathic pain in diabetic patients. The drug is available in clinical practice as a mixture of the (+)-tramadol and (-)-tramadol enantiomers. Tramadol is metabolized by CYP2D6 to O-desmethyltramadol (M1) and by CYP3A4 and CYP2B6 to N-desmethyltramadol (M2). Both tramadol enantiomers and (+)-M1 contribute to the analgesic activity of the drug: (+)-tramadol and the (+)-M1 metabolite act as -opioid receptor agonists; (+)-tramadol inhibits serotonin reuptake; and (-)-tramadol inhibits the reuptake of norepinephrine. This study investigated the influence of uncontrolled type 1 and type 2 diabetes mellitus (DM) on the kinetic disposition, metabolism and pharmacokinetics-pharmacodynamics of tramadol enantiomers in patients with neuropathic pain. Nondiabetic patients (control group, n = 12), patients with type 1 DM (n = 9), and patients with type 2 DM (n = 9), all with neuropathic pain and phenotyped as extensive metabolizers of CYP2D6, received a single oral dose of 100 mg racemic tramadol. Serial blood samples were collected up to 24 h after administration of the drug for pharmacokinetic study and for the analysis of noradrenaline in plasma. Pain was rated on a visual analog pain scale at the same time as blood sampling. The patients were evaluated for in vivo CYP3A activity using midazolam as a probe drug and genotyped for CYP2B6. Total and unbound plasma concentrations of the tramadol, M1 and M2 enantiomers were analyzed by LC-MS/MS using a Chiralpak® AD column. The kinetic disposition of tramadol was enantioselective in the control and type 1 DM groups, with the accumulation of (+)-tramadol. Type 1, but not type 2, DM reduced the AUC of the active (+)-M1 metabolite and simultaneously increased its unbound fraction. Therefore, unbound plasma concentrations of the (+)-M1 eutomer remain unchanged in patients with type 1 and type 2 DM. No differences in the plasma and urinary metabolic ratios of metoprolol/-hydroxymetoprolol or in midazolam clearance were observed between the control, type 1 and type 2 DM groups. The significant correlations seen between (+)-tramadol/(+)-M1 or (-)-tramadol/(-)-M1 AUC metabolic ratios and in vivo CYP2D6 activity evaluated in plasma or urine using metoprolol as a probe drug suggest the application of tramadol as a marker for CYP2D6. The data also showed a trend towards increased clearance of (+)-tramadol and (-)-tramadol as a result of the presence of mutant allele T in the 516G>T polymorphism of the CYP2B6 gene. The fractional sigmoid maximum drug effect model was used to describe the pharmacokinetic-pharmacodynamic relationship of tramadol in patients with neuropathic pain, associating the unbound plasma concentrations of (+)-M1 with the analgesic effect of tramadol. The present study highlights the importance of analyzing unbound concentrations of the individual tramadol enantiomers and its metabolites in pharmacokinetic-pharmacodynamic studies.
453

Pharmacocinétique de la ropivacaïne et de la lidocaïne au cours de la chirurgie carcinologique du sein et évaluation de la toxicité aux anesthésiques locaux en anesthésie locorégionale / Pharmacokinetic of ropivacaine and lidocaine in breast cancer surgery and evaluation of local anaesthetics in locoregional anesthesia

Riff, Camille 21 September 2018 (has links)
Ces dernières décennies, de nouvelles techniques d’anesthésie-analgésie locorégionales ont permis d’améliorer la prise en charge post-opératoire. Cependant, les anesthésiques locaux (AL) exposent les patients à un risque de toxicité systémique potentiellement fatale. La première étude est une étude rétrospective ayant inclus des cas potentiels de toxicité systémique aux AL. Cette étude a montré que, face à l’importante variabilité pharmacocinétique des AL observée, l’interprétation des concentrations est difficile. Sa contribution au diagnostic clinique est limitée aux prélèvements précoces après les signes de toxicité.La deuxième étude porte sur la pharmacocinétique de la lidocaine administrée en anesthésie locale tumescente. Il s’agit de la première description de sa pharmacocinétique dans cette indication. Les concentrations restent faibles pendant la durée de suivi. La modélisation par approche de population a permis de décrire le processus d’absorption systémique de la lidocaine après l’injection d’une solution tumescente. La troisième étude porte sur 10 patientes ayant reçu une infusion cicatricielle de ropivacaine de 40 heures. Il s’agit de la première description pharmacocinétique de l’infusion cicatricielle de ropivacaine dans cette indication. La modélisation a montré que l’absorption systémique de la ropivacaine est retardée et la concentration maximale est atteinte 2 heures après la fin de la perfusion. Les études rapportées dans cette thèse ont exploré les propriétés pharmacocinétiques des AL. L’objectif de ces travaux est de contribuer à une meilleure connaissance des thérapeutiques et de contribuer à une meilleure prise en charge des patients. / New locoregional anaesthetic techniques have permitted an improvement of care. However, local anaesthetics (LA) expose patients to systemic toxicity risks. It is essential to set guidelines for the use of these techniques. A retrospective study includes cases of suspected LA systemic toxicity. Systemic toxicity of LA occur when a large amount of LA reaches the systemic circulation. This thesis shows that the interpretation of plasmatic concentrations remains difficult because of the significant pharmacokinetics variability in the different nervous blocks. The second study deals with the population PK of lidocaine administrated in tumescent local anaesthetic. It is the first description of lidocaine PK is performed in this indication. The lidocaine concentrations remain low during the whole time of the operation. The modelling approach has allowed to highlight the slow systemic absorption process of lidocaine after injection of a tumescent solution. The third study focuses on the PK of ropivacaine administrated via continuous wound infusion in 10 women. It is the first time that the PK of ropivacaine administered using wound infusion is described. The modelling approach shows that systemic absorption of ropivacaine delayed and the maximal serum concentration is reached 2 hours after the end of ropivacaine infusion. These studies explored the PK properties of LA used as an anaesthetic or analgesic drug. The objective of this work is to contribute to a better knowledge of therapeutics and a better handling of patients.
454

Avaliação do perfil farmacocinético do flavonóide avicularina em ratos / Evaluation of the pharmacokinetic profile of the flavonoid avicularin in rats

Buqui, Gabriela Amaral 23 August 2013 (has links)
A substância 3-O-α-arabinofuranosil-quercetina (avicularina) é um flavonol já relatado em uma grande variedade de espécies vegetais, podendo ser encontrada em diversas frutas e plantas medicinais. Neste trabalho o flavonóide foi isolado da espécie Bidens sulphurea, popularmente conhecida como cosmo-amarelo, picãogrande e áster-do-méxico, com pureza de 93,27%. O flavonóide avicularina apresenta diversas propriedades biológicas descritas na literatura, e estudos científicos que comprovam a eficácia deste composto. No entanto não há estudos que avaliem os mecanismos que envolvem a farmacocinética (ADME) deste flavonóide, bem como sua biodisponibilidade. Sendo assim este trabalho teve como objetivo a determinação dos perfis farmacocinéticos de absorção da avicularina em ratos na presença e ausência de sais biliares e inibidor da glicoproteína-P, pelo ensaio de perfusão intestinal in situ. Neste trabalho também foi realizado a avaliação do perfil farmacocinético de distribuição e eliminação através de administração intravascular do flavonóide avicularina na dose de 1mg/kg em ratos. Para ambos os ensaios um método analítico sensível por CLUE-DAD-EM/EM foi desenvolvido e validado obedecendo às diretrizes do guia para validação de métodos bioanalíticos da ANVISA. Os ensaios de absorção com este flavonóide revelaram que sua taxa de absorção intestinal é baixa, em torno de 30% para as duas doses testadas (1 e 5 mg/kg), sugerindo uma baixa biodisponibilidade para este flavonóide. No entanto na presença do inibidor de glicoproteína-P, verapamil, o percentual absorvido final de avicularina foi de aproximadamente 80%, o que sugere o envolvimento de proteínas de efluxo em sua absorção. Através do estudo de farmacocinética com administração intravascular de avicularina pudemos concluir que o perfil farmacocinético do flavonóide em questão é bicompartimental, e possui rápida distribuição e eliminação do organismo, sendo o t ½α de 8 minutos e t ½β de 45 minutos, e, portanto baixa afinidade por tecidos, sendo baixa ou numa sua acumulação tecidual. / The compound 3-O-α-arabinofuranosyl-quercetin (avicularin) is a flavonol already reported in a wide variety of plant species and can be found in many fruits and medicinal plants. In this work the flavonoid was isolated from the species Bidens sulphurea, popularly known as yellow cosmos and aster of mexico, with 93.27% of purity. The flavonoid avicularin has several biological properties described in the literature, and several scientific studies that prove the efficacy of this compound. However there are no studies that evaluate the mechanisms involving the pharmacokinetics (ADME) of this flavonoid as well as its bioavailability. Thus, this study aimed to determine the pharmacokinetic profiles of avicularin absorption in rats in the presence and absence of bile salts and inhibitor of P-glycoprotein by in situ intestinal perfusion technique. This work was also performed to evaluate the pharmacokinetic profile of distribution and elimination through intravascular administration of the flavonoid avicularina at the dose of 1mg/kg in rats. For both studies a sensitive analytical UPLC-DAD/MS/MS method was developed and validated following the guidelines of the Guide for the validation of bioanalytical methods of ANVISA. The absorption assays have shown that with this flavonoid its intestinal absorption rate is low, around 30% for both tested doses (1 and 5 mg / kg), suggesting a low bioavailability of this flavonoid. However in the presence of Pglycoprotein inhibitors, verapamil, the percentage of absorbed avicularina was approximately 80%, suggesting the involvement of protein efflux in the absorption. Through pharmacokinetic study with intravascular administration of avicularin we could concluded that the pharmacokinetic profile of the flavonoid in question is twocompartmental model, and has quickly distribution and elimination of the organism, being the t ½α of 8 minutes, and t ½β of 45 minutes, thus this compound has low affinity for tissues, with low or none tissue accumulation.
455

Extração de Insumos farmacêuticos por fluído supercrítico / Extraction of pharmaceutical ingredients by supercritical fluid

Maul, Aldo Adolar 17 August 1998 (has links)
Não consta resumo na publicação / Abstracts not available.
456

Disposição cinética e transferência placentária dos enantiômeros da bupivacaína em parturientes portadoras do HIV em tratamento com antirretrovirais / Kinetic disposition and placental transfer of bupivacaine enantiomers in HIV-infected pregnant women in antiretroviral therapy

Souza, Marília Cristina Oliveira 06 March 2015 (has links)
A bupivacaína, um anestésico usado na anestesia e analgesia obstétrica, é disponível comercialmente como mistura racêmica dos enantiômeros (R)-(+)-bupivacaína e (S)-(-)-bupivacaína, os quais apresentam diferença na farmacocinética, eficácia e toxicidade. A bupivacaína é altamente ligada às proteínas plasmáticas, é substrato do transportador de efluxo glicoproteína-P (P-gp) e apresenta eliminação dependente do CYP3A4. Considerando que a infecção pelo HIV aumenta a expressão da P-gp na placenta, enquanto o tratamento com antirretrovirais (ARV) inibe o CYP3A4 e a P-gp, o presente estudo avalia a disposição cinética dos enantiômeros da bupivacaína em parturientes portadoras do HIV em tratamento com antirretrovirais (ARV). No presente estudo, foram investigadas 10 parturientes portadoras do HIV em tratamento com zidovudina, lamivudina, lopinavir e ritonavir. A anestesia ou analgesia foi realizada através da administração de cloridrato de bupivacaína 0,5% com epinefrina 1:200000 em espaço epidural, em doses de 2,5-22,5 mg. As amostras seriadas de sangue foram obtidas nos tempos imediatamente antes, 5, 15, 30, 45 e 60 min e em 2, 4, 6, 8, 10, 12 e 14h após a administração do anestésico bupivacaína. No momento do parto também foram coletadas amostras de sangue materno e sangue do cordão umbilical, para estudos de transferência placentária. Os métodos desenvolvidos e validados para a análise sequencial dos enantiômeros (+)-(R)-bupivacaína e (-)-(S)-bupivacaína como concentração total e como concentração livre em plasma empregando LC-MS/MS são compatíveis com a aplicação em estudo de farmacocinética em parturientes por apresentar as vantagens do baixo volume de plasma (200 ?L), corrida cromatográfica de aproximadamente 8 minutos, simples procedimento de extração líquido-líquido, baixo LIQ (0,25 ng de cada enantiômero/mL de plasma como concentração total e 0,125 ng de cada enantiômero/mL de plasma como concentração livre), extensa linearidade (0,25-500 ng de cada enantiômero/mL de plasma como concentração total e 0,125-10 ng de cada enantiômero/mL de plasma como concentração livre) e estabilidade assegurada em estudos de curta duração, ciclos de congelamento e pós-congelamento e pós-processamento. Os parâmetros farmacocinéticos dos enantiômeros da bupivacaína foram calculados com base nas curvas de concentração plasmática total versus tempo empregando o programa WinNonlin. A farmacocinética da bupivacaina é enantiosseletiva com acúmulo plasmático do enantiômero (S)-(-)-bupivacaína, com razão AUC (R)/(S) igual a 0,91 (p <0,05). A fração livre no plasma (Fu) é maior para o enantiômero (R)-(+)-bupivacaína, 9% (6 - 12), quando comparado ao enantiômero (S)-(-)-bupivacaína, 6 % (4 - 9) (p < 0,05). O tratamento com ARV, incluindo o ritonavir, infere interação enantiosseletiva entre os enantiômeros da bupivacaína e a P-gp placentária, com observação de maior inibição para o enantiômero (R)-(+)-bupivacaína. / Bupivacaine, an anesthetic used in obstetric anesthesia and analgesia is commercially available as a racemic mixture of (R)-(+)-bupivacaine and (S)-(-)-bupivacaine, which exhibit differences in pharmacokinetics, efficacy and toxicity. Bupivacaine is highly bound to plasma proteins, is a substrate of the efflux transporter P-glycoprotein (P-gp) and presents elimination dependent on CYP3A4. Whereas HIV infection increases the expression of P-gp in the placenta, while treatment with antiretroviral (ARV) inhibits CYP3A4 and P-gp, this study evaluates the kinetic disposition of the enantiomers of bupivacaine in pregnant women with HIV in antiretroviral therapy (ARV). In the present study, we investigated 10 pregnant women with HIV in treatment with zidovudine, lamivudine, lopinavir and ritonavir. Anesthesia or analgesia was performed using 0.5% bupivacaine with epinephrine administration of 1:200,000 in the epidural space, in doses of 2.5 to 22.5 mg. The serial blood samples were taken immediately before the time, 5, 15, 30, 45 and 60 min and 2, 4, 6, 8, 10, 12 and 14h after administration of the anesthetic bupivacaine. At delivery were also collected samples of maternal blood and cord blood, placental transfer studies. The methods developed and validated for sequence analysis of the enantiomers (+)-(R)-bupivacaine and (-)-(S)-bupivacaine and the total concentration as the free plasma concentration using LC-MS/MS spectra are consistent with the application of pharmacokinetic study in pregnant women to present the advantages of low plasma volume (200 ?L), chromatographic run approximately 8 minutes, simple liquid-liquid extraction procedure, low LLQ (0.25 ng each enantiomer/mL of plasma and total concentrations of each enantiomer 0.125 ng/mL as free plasma concentration), extended linearity (0.25 to 500 ng of each enantiomer/mL of plasma and the total concentration of each enantiomer from 0.125 to 10 ng/mL as concentration of plasma free), and ensured stability in short-term studies, cycles of freezing and post-freeze and post-processing. The pharmacokinetic parameters of bupivacaine enantiomers were calculated based on total plasma concentration curves versus time using WinNonlin program. Pharmacokinetics of bupivacaine is enantioselective with plasma accumulation of enantiomer (S)-(-)-bupivacaine with AUC ratio (R)/(S) equal to 0.91 (p <0.05). The free fraction in plasma (Fu) is higher for the enantiomer (R)-(+)-bupivacaine, 9% (6-12) enantiomer compared to the (S)-(-)-bupivacaine, 6% (4 - 9) (p <0.05). The ARV treatment, including ritonavir, infers enantioselective interaction between the enantiomers of bupivacaine and P-gp placental, highlighting greater inhibition of the enantiomer (R)-(+)-bupivacaine.
457

Durchflußzytometrische Untersuchungen zur zellulären Pharmakokinetik von freien und liposomal verkapseltem Daunorubicin

Bartels, Anna-Maria 04 July 2002 (has links)
In dieser Arbeit wurde die zelluläre Pharmakokinetik mit den Teilaspekten Invasion, Evasion und intrazellulärer Verteilung sowie die Apoptoseinduktion als Parameter der Pharmakodyna- mik von zwei Anthrazyklinen, dem freien und liposomal verkapseltem Daunorubicin unter- sucht. Die Versuche wurden anhand einer T-lymfatischen Zelllinie, den CEM-Zellen, durchgeführt. Mittels Durchflußzytometer und konfokaler Lasermikroskop wurde die intrazelluläre Fluoreszenz gemessen, die der intrazellulären Konzentration entsprach. Es zeigte sich, dass freies Daunorubicin anfangs deutlich schneller in die Zellen einströmte als liposomal verkapseltes Daunorubicin und früher die maximale Konzentration erreichte. Über eine längere Versuchszeit kam es aber zu einer Angleichung der maximal erreichten Konzen- trationen. Der Invasionsverlauf von Daunoxome verlief sigmoidförmig, während Daunorubi- cin einer Sättigungskinetik folgte. Der Invasionsverlauf beider Anthrazykline war sowohl zeit- als auch konzentrationsabhängig. Die Versuche zur intrazellulären Verteilung zeigten, dass sich beide Stoffe nach drei Stunden Inkubationszeit vom Zytoplasma in den Kern verteilten. Daunorubicin erreichte sehr schnell seine maximale Fluoreszenz im Kern. Bei Daunoxome ließ sich auch nach sechs Stunden Inkubation eine weitere Zunahme der Fluoreszenz messen. Die Untersuchungen zur Apoptoseinduktion unterstützten die Aussagen zur Invasion. Dauno- rubicin induzierte zu Anfang deutlich schneller Apoptose als Daunoxome. Über den gemessenen Versuchszeitraum kam es aber zu einer Angleichung aller Apoptoseraten. Auch hier zeigte sich eine Zeit- und Konzentrationsabhängigkeit. Die Ergebnisse der Evasionsversuche zeigten, dass Daunorubicin biphasisch und Daunoxome monophasisch ausströmte. Zusammenfassend kann gesagt werden, dass freies Daunorubicin initial eine bessere zelluläre Pharmakokinetik und damit eine höhere Zytotoxizität aufweist als liposomal verkapseltes Daunorubicin. Über die Zeit kommt es allerdings zu einer Angleichung der Zytotoxizität. Damit ist Daunoxome auf zellulärer Ebene mindestens genauso wirksam wie Daunorubicin. / We studied the cellular pharmacokinetics, including uptake, intracellular distribution and efflux, and the induction of apoptosis as a parameter of pharmacodynamics of the two anthracyclines, free and liposomal encapsulated daunorubicin. We used a flowcytometer and a confocal lasermicroscope to measure the intracellular fluorescence in CEM-cells, corresponding to the intracellular concentration of the drugs. Free daunorubicin invaded initially the cells much quicker than liposomal encapsulated daunorubicin and attained earlier the maximum concentration. After the examined time daunoxome achieved the same maximum concentration as daunorubicin. The invasion of liposomal encapsulated daunorubicin followed a sigmoid course, while free daunorubicin followed a saturation kinetic. It was shown that the uptake of both anthracyclines was time- and concentration-dependent. The examinations about the intracellular distribution showed, that both drugs accumulated in the nucleus after three hours of incubation. Daunorubicin attained quickly the maximum fluorescence there, while daunoxome increased slowly for the next six hours. The results of the apoptosis induction correlated to the results of the uptake experiments. Free daunorubicin induced initially quicker apoptosis than liposomal encapsulated daunorubicin. At the end of the measured time all the apoptosis rates of both drugs appeared to be equal. It was determined that the induction of apoptosis also is time- and concentration-dependent. The efflux of daunoxome was monophasic in contrast to a biphasic decline of daunorubicin. These results indicate that free daunorubicin has improved initial cellular pharmacokinetics and therefore enhanced cytotoxicity compared with liposomal encapsulated daunorubicin. But over the examined period both got equal cytotoxicity. Therefore daunoxome is on the cellular basis at least as effective as daunorubicin.
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Estudos in vitro e in vivo do metabolismo dos compostos majoritários presentes no extrato das folhas de Lychnophora salicifolia Mart. (Asteraceae: Vernonieae) / In vitro and in vivo metabolism of the major secondary metabolites present in the extract of Lychnophora salicifolia Mart. (Asteraceae: Vernonieae)

Gouvea, Dayana Rubio 08 October 2013 (has links)
A espécie Lychnophora salicifolia Mart. é conhecida popularmente como arnicão e é utilizada como anti-inflamatório e analgésico de uso tópico, além de edulcorante em cachaça. A vicenina-2 é um flavonoide C-glicosilado presente em grande quantidade no extrato hidroalcoólico das folhas e apresenta ação anti-inflamatória, antioxidante, anticâncer entre outras. Outra substância majoritária nesse extrato, o ácido lychnofólico, é um dos responsáveis pela ação antibacteriana e tripanocida do extrato. Devido à necessidade de estudos mais completos envolvendo produtos naturais, neste trabalho estudamos o metabolismo dessas duas moléculas sendo que não foi possível observar a formação de metabólitos in vitro a partir da vicenina-2 e no caso do ácido lychnofólico houve a formação de dois metabólitos pela adição de um átomo de oxigênio na molécula utilizando microssomas hepáticos de ratos. As mesmas substâncias foram formadas utilizando FeTFPP como catalisador e m-CPBA como agente oxidante. Nas reações com microssomas hepáticos humanos foi observada a conjugação do ácido lychnofólico com o ácido glucurônico sendo possível calcular: Vmáx = 272,5 ± 12,75 ?mol/g proteína/hora; Km = 12,38 ±1,218 ?M e o R2 = 0,9980. Os estudos com células Caco-2 indicam que o ácido lychnofólico é rapidamente absorvido por difusão passiva. Já a vicenina-2 em nenhuma condição avaliada atravessou a monocamada de células. Quanto ao perfil farmacocinético do ácido lychnofólico verificou-se um baixíssimo t1/2, alto Cl e alto Vd. Já a vicenina-2 apresentou valores um pouco maiores, mas ainda sim, baixos de t1/2 e Cl e Vd, indicando que ambas as substâncias são rapidamente eliminadas do organismo. / The species Lychnophora salicifolia Mart. popularly known as \"arnicão\" is used as an antiinflammatory and topical analgesic agent; it is also employed as flavoring in the Brazilian cachaça. Vicenin-2 is a C-glycoside flavonoid present in large amounts in the hydroalcoholic extract of the leaves of L. salicifolia and has anti-inflammatory, antioxidant, and anticancer activities. Another major substance in this extract is lychnopholic acid, which accounts for the antibacterial and trypanocidal actions of the extract. More comprehensive studies involving natural products are necessary; therefore, we studied the metabolism of the two aforementioned molecules. We did not observe the in vitro formation of metabolites from vicenin-2. In the case of lychnopholic acid, we detected the formation of two metabolites using rat liver microsomes, which possibly originated from the addition of an oxygen atom to the acid\'s molecule. The same substances may also have been produced when we employed FeTFPP as catalyst and m-CPBA as oxidizing agent. In the reactions involving human liver microsomes, we verified that lychnopholic acid conjugation with glucuronic acid and calculated the following parameters: Vmax = 272.5 ± 12.75 ?mol g-1 protein h-1; Km = 12.38 ± 1.218 ?M, and R2 = 0.9980. Studies using Caco-2 cells indicated that lychnopholic acid was quickly absorbed by passive diffusion. On the other hand, vicenin-2 was not transported, suggesting no absorption or efflux of this compound in Caco-2 cells. As for the pharmacokinetic profile, lychnopholic acid presented very low t1/2, high Cl, and very high Vd. Concerning vicenin-2, the t1/2 value was slightly larger, but still rather low, whereas Cl and Vd values were slightly lower, indicating that both substances are quickly eliminated from the body.
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Cinética de liberação de progesterona em dispositivos confeccionados a partir de blendas com PCL (Poli-&#603;-caprolactona) + PHB (Poli-hidroxibutirato) / Release kinetics of progesterone in devices made from blends with PCL (Poly-&#603;-caprolactone) + PHB (poly-hydroxybutyrate)

Miguez, Patrícia Helena Paiva 28 June 2011 (has links)
No Brasil, o uso da Inseminação Artificial em tempo fixo (IATF) vem crescendo rapidamente, uma vez que elimina a necessidade de observação do cio e induz a ciclicidade de vacas em anestro (MADUREIRA et al., 2004). Na maioria dos protocolos de IATF, empregam-se dispositivos de liberação sustentada de progesterona (P4) introduzidos na cavidade vaginal. Estes dispositivos são, na sua grande maioria, importados e confeccionados com uma armação de nylon, recoberta com silicone e progesterona. Visando a diminuição dos custos de produção e impacto ambiental, Pimentel (2006) confeccionaram dispositivos vaginais de liberação sustentada de progesterona, empregando uma mistura biopolimérica de PHB (Poli-hidroxibutirato) e PCL (poli-&#603;-caprolactona), para utilização no controle farmacológico do ciclo estral de vacas. No presente trabalho, foi estudado o mecanismo pelo qual, a progesterona é liberada da mistura biopolimérica (PHB46%+PCL46%+P48%). Para o estudo da cinética de liberação de P4 foram utilizados dispositivos (n=21) para experimento in vivo, onde foram introduzidos na cavidade vaginal das vacas e coletados a cada 24 horas durante 7 dias. Para experimentos in vitro foram utilizados 12 dispositivos que foram colocados em dissolutor de comprimidos e foram retirados em triplicata a cada 24 horas por 4 dias. Foi realizado experimento para avaliação da distribuição e quantidade de P4 em dispositivos de duas partidas diferentes em diversos pontos. A cinética de liberação de 4 tipos de dispositivos compostos de PHB+PCL+P4+ IrganoxB215&reg; adicionados ou não de um protetor anti raios ultra violeta ( Tinuvin&reg;) foi avaliada. Foi observado que a cinética de liberação de P4 se comportou de forma diferente entre sistemas in vivo e in vitro; em sistema in vivo foi de forma linear (R2=0,929), sugerindo que a progesterona possa ser liberada de acordo com o mecanismo de ordem zero e in vitro a liberação pode ser explicada pelo modelo matemático de Higuchi (R2=0,99) com o coeficiente de difusão calculado conforme a segunda lei de Fick foi de 2,09 x10-8 (cm2/s). Observou-se que a P4 no dispositivo está distribuída uniformemente (P= 0,519) e que aditivos e diferentes proporções de PHB+PCL não influenciaram a liberação de P4 por um período de 96 horas de testes in vitro. / In Brazil, the use of fixed-time artificial insemination (TAI) has been growing rapidly since it eliminates the need for estrus detection and induce cyclicity in anestrous cows (MADUREIRA et al., 2004). In most TAI protocols, devices are employed for the sustained release of progesterone (P4) introduced into the vaginal cavity. These devices are mostly imported and made with a nylon frame, covered with silicone and progesterone. Seeking to reduce production costs and environmental impact, Pimentel (2006) crafted devices for the sustained release vaginal progesterone, using a mixture biopolymer PHB (poly-hydroxybutyrate) and PCL (poly-&#603;-caprolactone), for use in pharmacological control estrous cycle of cows. In the present work was to study the mechanism by which the progesterone is released from the mixture biopolymers (PHB46 PCL46% +% +% P48). To study the kinetics of release of P4 device was used (n = 21) for in vivo experiment, where they were introduced into the vaginal cavity of cows and collected every 24 hours for 7 days. For in vitro experiments were used 12 devices were placed in dissolutor tablets and were taken in triplicate every 24 hours for 4 days. Experiment was conducted to assess the distribution and amount of P4 in two matches and different devices on several points. The release kinetics of four types of devices composed of PHB + PCL + P4 + IrganoxB215 &reg;, added to a protective anti ultraviolet rays (Tinuvin &reg;) was evaluated. It was observed that the kinetics of release of P4 behaved differently between systems in vivo and in vitro, the in vivo system was linear (R2 = 0.929), suggesting that progesterone may be released according to the mechanism of order zero and in vitro release can be explained by the mathematical model of Higuchi (R2 = 0.99) with the diffusion coefficient calculated according to Fick\'s second law was 2.09 x10-8 (cm2 / s). It was noted that a P4 is evenly distributed on the device (P = 0.519) and additives that different proportions of PHB and PCL + did not influence the release of P4for a period of 96 hours of in vitro tests.
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Évaluation par méthode in silico du risque d’émergence de la résistance bactérienne des antibiotiques : exemple des fluoroquinolones et des glycopeptides en gériatrie / In silico evaluation of the risks of emergence of bacterial resistance of antibiotics : case of fluoroquinolones and glycopeptides in geriatrics

Cazaubon, Yoann 06 November 2018 (has links)
La résistance bactérienne est une menace mondiale clairement établie. Les chercheurs se rassemblent afin de trouver de nouvelles solutions et des alternatives aux antibiotiques. Une des causes principales de cette menace est l’utilisation massive des antibiotiques. Il faut cesser d’avoir un recours déraisonné à leur usage. Au sein d’une population vieillissante, ce sont les personnes les plus vulnérables qui en payent le prix. Nous avons utilisé les outils de modélisation pour mieux comprendre les causes engendrant ce fléau. L'objectif de ce travail est de construire des modèles pharmacocinétique de population chez la personne âgée pour la vancomycine et la teicoplanine. À partir des modèles validés en amont ou bien issus de la littérature, des simulations ont été respectivement réalisées pour les glycopeptides et la ciprofloxacine dans le cas d’infections à Staphylococcus aureus résistant à la méthicilline et à Pseudomonas aeruginosa. Elles ont permis de mettre en évidence que lorsque la concentration minimale inhibitrice (CMI) de la bactérie incriminée était proche de la valeur critique de sensibilité, les doses à administrer pour être efficace doivent être augmentées par rapport aux recommandations actuelles. Quant à la prévention de l’émergence de la résistance bactérienne, dans le cas de la ciprofloxacine et de la teicoplanine, les doses à administrer sont telles que la toxicité est inévitable. Les analyses faites aux moyens des simulations de Monte Carlo sur les antibiotiques étudiés ont permis de mieux comprendre les déterminants de la minimisation de l’émergence de la résistance bactérienne à savoir obtenir dans les plus brefs délais la CMI exacte de la bactérie en cause ainsi qu’une estimation des paramètres individuels du patient / Bacterial resistance is a clearly established global threat. Researchers are coming together to find new solutions and alternatives to antibiotics. One of the main causes is the massive use of antibiotics. The unreasonable recourse of their use must be stopped. The population is aging, so it is the most vulnerable people who pay the price. We have used modeling tools to better understand the causes of this scourge. The goal of this work is to construct population pharmacokinetic models in the elderly for vancomycin and teicoplanin. From models validated upstream or from the literature, simulations have been performed for glycopeptides and ciprofloxacin for methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa infections, respectively. They showed that when the minimal inhibitory concentration (MIC) of the incriminated bacterium was close to the critical value of sensitivity, the doses to be administered in order to be effective have to be increased compared to current recommendations. As for the prevention of the emergence of bacterial resistance, in the case of ciprofloxacin and teicoplanin, the doses to be administered are so high that toxicity is unavoidable. Analyses using Monte Carlo simulations on the antibiotics studied provided a better understanding of the determinants of minimizing the emergence of bacterial resistance to obtain as quickly as possible the exact MIC of the bacteria and an estimation of individual patient parameters

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