Les récepteurs nucléaires des xénobiotiques et les enzymes métaboliques P450 (CYP) constituent les principaux éléments contrôlant la biotransformation des médicaments, ainsi que le maintien de des barrières physiologiques au niveau périphérique, plus particulièrement, dans le foie et dans l’intestin. Plusieurs études ont mis en évidence la présence des CYP ainsi que les récepteurs nucléaires contrôlant leur expression, tels que le Constitutive Androstane Receptor et le Pregnane Xenobiotic Receptor (CAR et PXR). Des résultats précédant indiquent la surexpression des CYP2E1 et CYP3A4 dans des tissus et des cellules isolées du cerveau de patients épileptiques pharmacorésistants. L’importance de ces résultats réside dans le rôle du CYP2E1 et CYP3A4 dans la biotransformation de plusieurs médicaments antiépileptiques (MAE) suggérant ainsi un mécanisme de pharmacorésistance aux médicaments. Contrairement aux autres récepteurs nucléaires, les fonctions physiologiques des récepteurs nucléaires des xénobiotiques au niveau vasculaire sont mal connues. Nos résultats montrent des changements spatio-temporaux de l’expression des CYP2E1 et CYP3A4 dans le cerveau après une crise aigüe et pendant le processus d’épileptogenèse chez la souris. Une exposition in vivo et in vitro au MAE Phénytoïne induit une augmentation du niveau du CYP2E1. Le Phénobarbital et la Carbamazépine n’ont pas eu d’effet. Les souris privées des récepteurs nucléaires des xénobiotiques (PXR KO et CAR KO) ne présentent pas de changement de niveau basal des CYP dans le cerveau. Cependant, les souris CAR KO présentent des dysfonctionnements neuronaux (altération de la mémoire, comportement anxieux et une diminution de l’intensité des rythmes EEG entre 3.5-7 Hz) et des modifications caractérisées par une augmentation de perméabilité vasculaire et une dispersion des neurones hippocampiques. L’ensemble des résultats indique une régulation dynamique des CYP dans le cerveau avec une extension de l’impact des récepteurs des xénobiotiques à des fonctions neurovasculaires. / Xenobiotic nuclear receptors and P450 metabolic enzymes (CYP) are pivotal controllers of drug biotransformation and barrier functions in peripheral organs, including the intestine and the liver. Accumulating evidence suggested that, in human, central nervous system cells express significant levels of P450 enzymes and their upstream regulators e.g. Constitutive Androstane and Pregnane Xenobiotic Receptors (CAR, PXR). We previously showed the increased and ectopic CYP2E1 and CYP3A4 expression in brain specimens or cells obtained from drug resistant epileptic patient. These results are significant as CYP2E1 and CYP3A4 are responsible for the metabolism of several antiepileptic drugs (AED), therefore, suggesting a possible new mechanism of drug resistance. However, the exact determinants of CYP expression in the epileptic brain remain unknown. In addition, the exact role of nuclear xenobiotic receptor in the brain is understudied. The latter represents a significant knowledge gap as nuclear receptors other than the xenobiotic ones were shown to contribute to physiological neurovascular functions. Our results show spatio-temporal changes of CYP2E1 and CYP3A4 brain expression occuring after status epilepticus and during epileptogenesis in mice. Exposure to the AED phenytoin, phenobarbital, but not carbamazepine, increased brain CYP2E1 expression in vivo and in vitro. Lack of the specific xenobiotic receptors CAR and PXR did not impact basal CYP brain levels. However, we found an unexpected contribution of CAR to neuronal dysfunctions (memory impairment, anxiety like-behavior and decrease 3.5-7 Hz EEG waves) and neurovascular development, as indicated by increase vascular permeability and hippocampal neuronal dispersion. These results depict a dynamic regulation of P450 enzymes in the brain also expanding the impact of xenobiotic receptors to previously unexplored neurovascular functions.

NADPH-P450 oxidoreductase (POR) is a membrane bound flavoprotein that donates electrons to a wide spectrum of heme-containing proteins, among which are several steroidogenic and many xenobiotics-metabolizing enzymes. Given the important role of POR protein in drug metabolism and pharmacogenomics, there is a particular need to understand the contributions of POR genetic variants to these processes. Mutations in POR gene cause a disorder called POR deficiency, which manifests with a wide phenotypic spectrum ranging from disordered steroidogenesis to skeletal malformation, namely, Antley-Bixler syndrome (ABS). The aim of the present work was to investigate the POR gene in patients suspected to have POR deficiency syndrome from Czech Republic and to perform genotyping in Czech and Jewish control populations. We analyzed 644 alleles in unrelated individuals from the general Czech population and 1128 alleles in Jewish population, where 330 alleles were of Askhenazi and 798 of Sephardic Jews. We have also studied the impact of selected new genetic variants on POR activity and identified fourteen amino acid variations, two of which we have studied in detail to establish their influence on POR activity. Using the available human POR three-dimensional structure, we then modelled the newly identified variants...

This dissertation aimed at developing an inhibitor strategy to improve the oral bioavailability (Foral) and systemic exposure (AUC∞) of buprenorphine (BUP) as well as reduce the variability associated with them. Twenty-seven generally recognized as safe (GRAS) compounds or dietary substances were evaluated for their potential to inhibit the oxidative and conjugative metabolism of BUP, using pooled human intestinal and liver microsomes. In both the organs, oxidation appeared to be the major metabolic pathway with a 6 fold (intestine) and 4 fold (liver) higher intrinsic clearance than glucuronidation. Buprenorphine was predicted to show low and variable Foral, AUC∞, and a large total clearance. The biorelevant solubilities of 5 preferred inhibitors were incorporated in the final model. An inhibitor dosing strategy was identified to increase Foral and reduce the variability in oral BUP AUC∞. These results demonstrate the feasibility of the approach of using GRAS or dietary compounds to inhibit the presystemic metabolism of buprenorphine and thus improve its oral bioavailability. This inhibitor strategy has promising applicability to a variety of drugs suffering from low and variable oral bioavailability due to extensive presystemic oxidative and conjugative metabolism.

Sunitinib, an oral vascular endothelial growth factor receptor, is a first-line option for metastatic renal cell carcinoma and widely used in clinical practice. Despite the proven benefit of sunitnib in metastatic renal cell carcinoma, patients may suffer from a variety of adverse events including hypertension, fatigue, hypothyroidism, hand?foot skin reactions, rash, depigmentation, and myelosuppression. Myelosuppression is usually mild, transient and resolves during the two weeks at the end of each cycle where no drug is taken. We present a case of severe and early grade 3 neutropenia and thrombocytopenia occurring two weeks into a six-week cycle. Because of the extreme nature of the toxicity, CYP 3A4 polymorphisms were explored. The patient was found to be heterozygous for CYP 3A4*22, at least partially explaining the early-onset and severity of myelosuppression. This pharmacogenetics information resulted in a rechallenge of dose-reduced sunitinib, which was well tolerated by the patient. The current state of pharmacogenomics concerning sunitinb is also presented, and the need for greater research in this area is highlighted.

Retinoic Acid Metabolism Blocking Agents (RAMBAs) increase the endogenous levels of all-trans retinoic acid (RA) by inhibiting CYP26 enzymes. Thus they are believed to mimic the effects of retinoid treatment. Their mechanism of action and effects on vitamin A metabolism in keratinocytes are however uncertain. To explore this and the function of CYP26 in human skin was the main purpose of the project. The effects of two RAMBAs (talarozole and liarozole) on the expression of retinoid biomarkers in epidermis were studied in vivo and in vitro. Normal human skin (n=16) exposed to topical talarozole for 9 days showed similar response as previously reported for topical RA, even though no skin inflammation occurred. Lamellar ichthyosis patients (n=11) treated systemically with liarozole showed variable clinical improvement after 4 weeks with only mild effects on the retinoid biomarkers and the expression did not always correlate at the protein and mRNA levels. In these studies the proinflammatory transcripts IL-1α and TNFα were down-regulated by RAMBAs. In vitro, using an organotypic epidermis model we first studied how the RA metabolism was affected by adding RA and/or RAMBAs. We next examined the effects of the same agents on the expression of vitamin A metabolising enzymes in monolayer cultures of proliferating and differentiating keratinocytes. The results show among other things that CYP26 A1 and B1 are both involved in the catabolism of RA, and that talarozole potently increases the level of endogenous RA, primarily by inhibiting CYP26B1. However the drug´s biological effects cannot be solely attributed to increased RA levels. In conclusion, RAMBAs are promising new drugs for treatment of skin disorders, but further studies on their mechanism of action are needed.

Made available in DSpace on 2014-12-17T14:03:35Z (GMT). No. of bitstreams: 1 AmandaLMM_DISSERT.pdf: 1135135 bytes, checksum: 22f94cd634c60ab505070e7d4ae43900 (MD5) Previous issue date: 2010-08-31 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / In this work, we used sugarcane as a model due to its importance for sugar and ethanol production. Unlike the current plant models, sugarcane presents a complex genetics and an enormous allelic variation. Here, we report the analysis of SAGE libraries produced using the shoot apical meristem from contrasted genotypes by flowering induction (non-flowering vs. early-flowering varieties) grown under S?o Paulo state conditions. The expression pattern was analyzed using samples from S?o Paulo (SP) and Rio Grande do Norte (RN) states. These results showed that cDNAs identified by SAGE libraries had differential expression only in S?o Paulo state samples. Furthermore, the cDNA identified CYP (Citocrome P450) was chosen for in silico and genome characterization because it was found in SAGE libraries and subtractive libraries from samples from RN. Phylogenetic trees showed the relationship for these sequences. Furthermore, the qRT-PCR for CYP showed a potential role as flowering indutor for RN samples considering different isophorms. Considering the results present here, it can be consider that CYP gene may be used as molecular marker / A cana-de-a??car ? um modelo devido ? sua import?ncia na produ??o de ?lcool e a??car. Diferente de outras plantas modelo, ela apresenta um genoma complexo e muita varia??o al?lica. Foram analisadas as bibliotecas SAGE produzidas a partir de ?pices meristem?ticos de cana-de-a??car de gen?tipos tardio e precoce, quanto ao florescimento, cultivados no estado de S?o Paulo. A express?o destes cDNAs prospectados foi analisada usando amostras de S?o Paulo e do Rio Grande do Norte. Estes resultados mostraram que os genes apresentavam express?o diferencial apenas para os gen?tipos cultivados em S?o Paulo. Entretanto, o cDNA CYP (Citocromo P450), foi escolhido para uma an?lise in silico e caracteriza??o gen?tica por ter sido identificado tanto nas bibliotecas SAGE como em bibliotecas subtrativas realizadas com gen?tipos cultivados no Rio Grande do Norte. ?rvores filogen?ticas mostraram a rela??o evolutiva entre as sequ?ncias. Al?m disso, dados de qRT-PCR para CYP51 mostram um poss?vel papel indutor de flora??o nas condi??es do RN. Considerando os resultados apresentados, podemos inferir que o gene CYP51 pode ser utilizado como marcador molecular para o melhoramento cl?ssico

<p>CYPs are a large and diverse protein superfamily found in all domains of life and are able to metabolize a wide array of both exogenous and endogenous molecules. The CYPome of the polychaete annelid Capitella teleta has been robustly identified and annotated with the genome assembly available (version 1). Annotation of 84 full length and 12 partial CYP sequences predicted a total of 96 functional CYPs in C. teleta. A further 13 CYP fragments were found but these may be pseudogenes. The C. teleta CYPome contained 24 novel CYP families and seven novel CYP subfamilies within existing families. A phylogenetic analysis was completed, primarily with vertebrate sequences, and identified that the C teleta sequences were found in 9 of the 11 metazoan CYP clans. Clan 2 was expanded in this species with 51 CYPs in 14 novel CYP families containing 20 subfamilies. There were five clan 3, four clan 4, and six mitochondrial clan full length CYPs. Two CYPs, CYP3071A1 and CYP3072A1, did not cluster with any metazoan CYP clan. C. teleta had a CYP51A1 gene with ~65% identity to vertebrate CYP51A1 sequences and was predicted to have lanosterol 14 α-demethylase activity. Several CYPs (CYP376A1, CYP3068A1, CYP3069A1, and CYP3070A1) are discussed as candidate genes for steroidogenesis. There are two CYP1-like CYPs and a total of four CYP331s found in C. teleta, which may play a role in PAH metabolism and warrant further analysis.</p> / Master of Science (MSc)

Mehrfach ungesättigte omega-3 Fettsäuren (n-3 PUFAs), wie Eicosapentaensäure (EPA) und Docosahexaensäure (DHA), schützen vor kardiovaskulären Erkrankungen, wie tödlichen Arrhythmien. In vitro Untersuchungen belegen, dass rekombinante Cytochrom P450 (CYP) Enzyme nicht nur die n-6 PUFA Arachidonsäure (AA), sondern auch die n-3 PUFAs EPA und DHA als alternative Substrate verwenden. Dabei entstehen bioaktive regio- und stereoisomere Epoxy- und Hydroxymetaboliten, CYP-Eicosanoide, die als sekundäre Botenstoffe bei der Regulation von Gefäß-, Nieren- und Herzfunktionen fungieren. Die genauen molekularen Mechanismen dieser Metabolite sind noch weitgehend unerforscht. In der vorliegenden Arbeit wurde zunächst der ernährungsbedingte Einfluss auf das endogene CYP-Eicosanoidprofil im Menschen untersucht. Die Ergebnisse der klinischen Studie zeigten, dass n-3 PUFAs auch in vivo alternative Substrate von CYP-Enzymen darstellen und wenn verfügbar sogar effektiver zu ihren Metaboliten umgesetzt wurden als AA. Als ein wichtiger Metabolit entsteht nach EPA/DHA-Supplementation 17,18-EEQ, welcher womöglich der eigentliche Vermittler der kardioprotektiven Effekte von n-3 PUFAs ist. Unter Verwendung eines etablierten Zellmodells mit spontan schlagenden neonatalen Rattenkardiomyozyten (NRKMs) wurde der anti-arrhythmische Effekte von 17,18-EEQ genauer untersucht. Der negativ chronotrope Effekt von EPA auf NRKMs wurde tatsächlich durch 17,18-EEQ vermittelt, insbesondere dem R,S-Enantiomer. Mittels Strukturfunktionsanalyse wurden synthetische Analoga mit gleicher Wirksamkeit wie dem 7,18-EEQ gefunden, wobei strikte strukturelle Merkmale für die biologische Funktion identifiziert wurden. Die Suche nach einem molekularen Ziel für CYP-Epoxyeicosanoide führte zu einem möglichen Rezeptorkandidaten, der hinsichtlich seiner Ligandenspezifität untersucht wurde. Dieser oder zukünftige andere Rezeptorkandidaten stellen ein mögliches neues zelluläres Ziel zur Behandlung kardialer Arrhythmien dar. / The n-3 polyunsaturated fatty acids (n-3 PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), protect from cardiovascular disease, especially from fetal arrhythmia. Moreover, in vitro studies proved that recombinant cytochrome P450 (CYP) enzymes not only accept the physiologically most important n-6 PUFA arachidonic acid (AA), but also EPA and DHA as alternative substrates, thereby generating regio- and stereospecific biologically active epoxy- and hydroxymetabolites, CYP-eicosanoids. These metabolites serve as second messengers regulating vascular, renal and cardiac function. The precise underlying molecular mechanisms are only partially understood and need further investigation. The first aim of the thesis was to show that the endogenous CYP-eicosanoid profile depends on the availability of the precursor fatty acids. The results of a clinical trial with 20 volunteers, show that n-3 PUFAs serve also in vivo as alternative CYP-dependent substrates and are even preferentially metabolized compared to AA. After EPA/DHA-supplementation 17,18 EEQ was generated as a major metabolite, potentially an important mediator of cardiovascular effects originally attributed to n-3 PUFAs. To test the anti-arrhythmic effect of EPA and 17,18-EEQ, an established cell model with neonatal rat cardiomyocytes (NRKMs) was used. The negative chronotropic effect of EPA was mimicked by 17,18-EEQ, attributed only to the R,S-enantiomer. A structure activity relationship study revealed synthetic analogs, exerting the same biological effect as 17,18-EEQ. Strict structural requirements were found for agonistic function, hinting at a specific interaction with cellular targets, like GPCRs. The search of a molecular target of CYP-eicosanoids led to a putative receptor, which was tested for ligand binding specificity. If the preliminary results on the ligand binding are confirmed in future experiments this receptor might be a novel target for the treatment of cardiac arrhythmia.

Die Bedeutung genetischer Polymorphismen im Enzym Cytochrom P450 2C9 für Pharmakokinetik und Wirkungen von Diclofenac und Ibuprofen Es wird angenommen, dass Cytochrom-P450 2C9 die 4’-Hydroxylierung des Nichtsteroidalen Antiphlogistikums Diclofenac und die Hydroxylierung von S-Ibuprofen beim Menschen katalysiert. Es existieren zwei Varianten von Cyp2C9. Deren Auswirkungen auf die Diclofenac- bzw. Ibuprofen-Pharmakokinetik und die Hemmung von Cox-1 und -2 wurde an 21 gesunden Probanden, die sämtliche Kombination der genetischen Varianten *2 und *3 aufwiesen, untersucht. Es zeigten sich keinerlei Hinweise auf eine Einschränkung des Metabolismus von Diclofenac bei heterozygoten und homozygoten Trägern der Cyp2C9-Allele *2 und *3. Darüber hinaus lagen auch die Serumkonzentrationen des Metaboliten 4’-OH-Diclofenac bei Trägern der Allele Cyp2C9 *2 und *3 nicht niedriger. Obwohl verschiedene in vitro-Untersuchungen Cyp2C9 als metabolisierendes Enzym identifizierten, ist die Pharmakokinetik von Diclofenac ist beim Menschen entweder überhaupt nicht oder nur in geringem Ausmaß von Cyp2C9-Aminosäurenpolymorphismen abhängig. Möglicherweise sind die Auswirkungen der Cyp2C9-Aminosäurenvarianten substratabhängig, oder es ist in vivo ein anderes Enzym als Cyp2C9 verantwortlich für die Bildung von 4’-OH-Diclofenac. Im Unterschied dazu hing die Pharmakokinetik von razemischem und von S-Ibuprofen vom Cyp2C9 *3-Polymorphismus ab. Die Bildung von Tx B2 (Cox-1) hing signifikant von Cyp2C9 *3-Polymorphismus ab, derselbe Trend ließ sich auch für Pg E2 (Cox-2) beobachten. Die eingeschränkte Clearance von S-Ibuprofen, die mit einer erhöhten pharmakodynamischen Aktivität einhergeht, legt nahe, dass Träger des Allels Cyp2C9*3 ein höheres Risiko tragen, nach Einnahme einer oralen Standarddosis unerwünschte Nebenwirkungen zu erleiden. / Consequences of genetic polymorphisms in Cytochrome P450 2C9 for pharmacokinetics and effects of Diclofenac and Ibuprofen. Cytochrome-P450 2C9 is considered to catalyse the 4’-hydroxylation of the nonsteroidal analgesic drug diclofenac and the hydroxylation of S-ibuprofen in humans. There are two variants of Cyp2C9. Their impact on diclofenac/ ibuprofen pharmacokinetics and on the inhibition of cyclooxygenases 1 and 2 was studied in 21 healthy volunteers with all combinations of the Cyp2C9 variants *2 and *3. Blood concentrations of diclofenac/ racemic ibuprofen (and of S-ibuprofen and R-ibuprofen) were measured by HPLC. Thromboxane B2 and prostaglandin E2 were measured with use of an enzyme immunoassay. There was no evidence of impaired metabolism of diclofenac in heterozygous and homozygous carriers of the Cyp2C9 alleles *2 and *3 compared to the wildtype. Furthermore, plasma concentrations of the metabolite 4’-OH-diclofenac were not lower in carriers of Cyp2C9*2 and *3. Marked diclofenac mediated inhibition of Cox-1- and Cox-2 activity was detected in all individuals without any Cyp2C9 genotype dependent differences. Even though several in vitro studies identified Cyp2C9 as the metabolising enzyme, Diclofenac pharmacokinetics in humans is either not or only to a minor extend dependent on the Cyp2C9 amino acid polymorphisms. It may be that the Cyp2C9 amino acid variants have differential effects depending on the substrates. Alternatively, an enzyme other than Cyp2C9 may be responsible for 4’-OH-Diclofenac formation in vivo.In contrast, the pharmacokinetics of racemic and of S-ibuprofen depended on the Cyp2C9 *3-polymorphism. The Cyp2C9 variant *2 exhibited no significant effect. Formation of Tx B2 (cox-1) depended significantly on the Cyp2C9 polymorphism, the same trend was observed for Pg E2 (cox-2). The reduced S-ibuprofen total clearance accompanied by increased pharmacodynamic activity indicates an increased risk for carriers of Cyp2C9*3 to suffer from adverse effects after intake of a standard oral dose.

O carvedilol é um anti-hipertensivo disponível na clínica como mistura racêmica, sendo o (S)-(-)-carvedilol um bloqueador ? e ?1-adrenérgico e o (R)-(+)-carvedilol apenas ?1-adrenérgico. O carvedilol é metabolizado principalmente por glicuronidação e pelo CYP2D6 a hidroxifenilcarvedilol e pelo CYP2C9 a Odesmetilcarvedilol. O presente estudo avalia a disposição cinética e o metabolismo dos enantiômeros do carvedilol, hidroxifenilcarvedilol e O-desmetilcarvedilol em voluntários sadios não comedicados (n=13) ou comedicados com dose única oral de glibenclamida (5 mg) e metformina (500 mg) (n=13) e em pacientes portadores de diabetes mellitus tipo 2 (com bom controle glicêmico e em tratamento com glibenclamida 5 mg/8h e metformina 500 mg/8h; n=14), fenotipados como metabolizadores rápidos (n=26) ou lentos (n=1). Os voluntários e pacientes receberam dose única oral de 25 mg de carvedilol racêmico e amostras seriadas de sangue foram coletadas até 24h após a administração. A frequência cardíaca foi avaliada na situação de exercício isométrico com o handgrip durante 2 min a 30% da contratilidade voluntária máxima e durante o repouso. Os enantiômeros do carvedilol e metabólitos foram analisados em plasma por LC-MS/MS empregando coluna Chirobiotic® V. O método foi linear no intervalo de 0,05 a 100; 0,05 a 10 e 0,02 a 10 ng/mL para os enantiômeros do carvedilol, hidroxifenilcarvedilol e O-desmetilcarvedilol, os desvios do estudo de precisão e exatidão foram inferiores a 15% e não foi observado efeito matriz. A farmacocinética avaliada por modelo não compartimental mostra acúmulo plasmático dos enantiômeros (R)-(+)-carvedilol, (R)-(+)-O-desmetilcarvedilol e (R)-(+)- hidroxifenilcarvedilol. A disposição cinética e o metabolismo dos enantiômeros do carvedilol não diferem entre os grupos de voluntários não comedicados e comedicados com dose única oral de glibenclamida e metformina. No entanto, os valores de AUC de ambos os enantiômeros do metabólito O-desmetilcarvedilol [(R)- (+): 6,92 vs 10,40 vs 11,91 ng.h/mL e (S)-(-): 2,36 vs 4,26 vs 3,98 ng/h/mL] são menores no grupo de pacientes portadores de diabetes mellitus tipo 2 quando comparados ao grupo de voluntários sadios não comedicados ou comedicados. Em compensação, os valores de AUC de ambos os enantiômeros do metabólito hidroxifenilcarvedilol [(R)-(+): 13,89 vs 6,60 vs 4,88 ng.h/mL e (S)-(-): 7,21 vs 1,50 vs 1,45 ng/h/mL] são maiores no grupo de pacientes portadores de diabetes mellitus tipo 2. Os parâmetros farmacocinéticos de um paciente metabolizador lento do CYP2D6, portador de diabetes mellitus tipo 2 e em tratamento com glibenclamida e metformina, permite inferir redução na formação de ambos os enantiômeros do metabólito hidroxifenilcarvedilol compensada pelo aumento na formação de ambos os enantiômeros do metabólito O-desmetilcarvedilol. Logo, a disposição cinética de ambos os enantiômeros do carvedilol sob a forma inalterada não difere entre metabolizadores rápidos e lentos do CYP2D6. O modelo não linear de efeitos mistos para a análise da disposição cinética e metabolismo populacional dos enantiômeros do carvedilol foi desenvolvido no NONMEM v.7.2 é preciso e possui capacidade preditiva adequada avaliada por métodos visuais do ajuste do modelo aos dados e ii bootstrap. Os valores de biodisponibilidade estimados pelo modelo para os enantiômeros (S)-(-) e (R)-(+)-carvedilol, respectivamente 16,43 e 25,4%, não diferem entre voluntários sadios e pacientes portadores de diabetes mellitus tipo 2 em tratamento com glibenclamida e metformina. Os valores de clearance pelo CYP2D6 estimados para o (S)-(-)-carvedilol foram de 1,65 vs 7,28 L/h, respectivamente, para os voluntários sadios e para os pacientes diabéticos, enquanto os estimados para o enantiômero (R)-(+)-carvedilol foram de 2,69 vs 13,7 L/h. Em relação ao clearance pelo CYP2C9, os valores estimados para o (S)-(-)-carvedilol foram de 16,2 vs 7,71 L/h, respectivamente, para os voluntários sadios e para os pacientes diabéticos, enquanto os estimados para o enantiômero (R)-(+)-carvedilol foram de 25,6 vs 10,5 L/h. Os valores de clearance por outras vias metabólicas são maiores para o (S)-(-)- carvedilol do que para o (R)-(+)-carvedilol (28,2 vs 4,86 L/h) e não diferem entre voluntários sadios e pacientes. Os valores de clearance total de ambos os enantiômeros do carvedilol não diferem entre os voluntários sadios e os pacientes portadores de diabetes mellitus tipo 2 [(S)-(-): 46,05 vs 43,19 L/h e (R)-(+): 33,15 vs 29,06 L/h], considerando que os menores clearances do CYP2C9 são compensados por maiores clearances do CYP2D6. A variação da frequência cardíaca induzida pelo exercício isométrico com o handgrip após a administração de dose única oral de 25 mg de carvedilol racêmico não mostra relação com as concentrações plasmáticas do (S)-(-)-carvedilol. / Carvedilol is an antihypertensive available as racemic mixture, the (S)-(-)- carvedilol is a ??and ?1 adrenergic blocker and (R)-(+)-carvedilol is only na ?1- adrenergic blocker. Carvedilol is metabolized primarily by glucuronidation and by CYP2D6 to hidroxifenilcarvedilol and CYP2C9 to O-desmetilcarvedilol. This study evaluates the disposition and metabolism of carvedilol, hidroxyphenilcarvedilol and Odesmethylcarvedilol enantiomers in health (n=13) and type II diabetes subjects treated with glibenclamide (5 mg/8h) and in a good glycemic control (n=13) and in a CYP2D6 poor metabolizer diabetes subject (n=1). The subjects received a single racemic carvedilol dose of 25 mg. blood samples wore collected until 24h. The heart rate was evaluated durig isometric handgrip exercise. Carvedilol and metabolites enantiomers wore evaluated in plasma sampels by LC-MS/MS. The pharmacokinetics was evaluate by noncompartimental model and higher levels of (R)-(+)-carvedilol, (R)-(+)-Odesmethylcarvedilol e (R)-(+)-hidroxiphenilcarvedilol levels are noticed. The carvedilol pharmacokinetics does not change between healthy and type II diabetes subjects. However the AUC values of both O-desmethylcarvedilol enantiomers are lower [(R)-(+): 6,92 vs 10,40 vs 11,91 ng.h/mL e (S)-(-): 2,36 vs 4,26 vs 3,98 ng/h/mL]in the diabetes subjects and the AUC values of both hidroxyphenilcarvedilol enantiomers are higher [(R)-(+): 13,89 vs 6,60 vs 4,88 ng.h/mL e (S)-(-): 7,21 vs 1,50 vs 1,45 ng/h/mL]. It is noticed in CYP2D6 poor metabolizer diabetes subject lower levels of hidroxyphenilcarvedilol but higher of O-desmetilcarvedilol and carvedilol disposition is not changed. A Non-linear mixed effects modelling was performed in NONMEM v.7.2 the model was validated by visual methods and bootstrap. The bioavailability of (S)-(-) and (R)-(+)-carvedilol was 16,43 e 25,4% and no covariate effect was noticed. The CYP2D6 clearance values were 1,65 vs 7,28 L/h to healthy and diabetes subjects, inasmuch (R)-(+)-carvedilol ones were 25,6 vs 10,5 L/h. The CYP2C9 clearance of (S)-(-)-carvedilol were 16,2 vs 7,71 L/h for healthy and diabetes subjects, while (R)- (+)-carvedilol ones were 25,6 vs 10,5 L/h. The (S)-(-)-carvedilol clearance by other metabolic routes are higher (28,2 vs 4,86 L/h) and does not change between healthy and diabetes subjects. Carvedilol total clearance also does not differ between healthy and diabetes subjects the because the lower CYP2C9 clearance are balanced by the higher CYP2D6 clearance. The cardiac frequency change induced by handgrip isometric exercise is not related with the (S)-(-)-carvedilol plasma levels.