Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
Int Clin Psychopharmacol ; 32(1): 27-35, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27643885

RESUMO

The aim of this study is to evaluate the effects of vilazodone on sexual functioning in healthy, sexually active adults and assess the impact of medication nonadherence in this type of trial. Participants were randomized to vilazodone (20 or 40 mg/day), paroxetine (20 mg/day), or placebo for 5 weeks of double-blind treatment. The primary endpoint was change from baseline to day 35 in Change in Sexual Functioning Questionnaire (CSFQ) total score in the intent-to-treat (ITT) population. Post-hoc analyses were carried out in modified intent-to-treat (mITT) populations that excluded participants in the active-treatment groups with undetectable plasma drug concentrations at all visits (mITT-I) or at least one visit (mITT-II). In the ITT population (N=199), there were no statistically significant differences between any treatment groups for CSFQ total score change: placebo, -1.0; vilazodone 20 mg/day, -1.4; vilazodone 40 mg/day, -1.9; and paroxetine, -3.5. In mITT-I (N=197) and mITT-II (N=159), CSFQ total score change was not significantly different between vilazodone (either dose) versus placebo; the CSFQ total score decreased significantly (P<0.05) with paroxetine versus both placebo and vilazodone 20 mg/day, but not versus vilazodone 40 mg/day. Vilazodone exerted no significant effect on sexual functioning in healthy adults. Medication nonadherence can alter study results and may be an important consideration in trials with volunteer participants.


Assuntos
Inibidores Seletivos de Recaptação de Serotonina/farmacologia , Comportamento Sexual/efeitos dos fármacos , Comportamento Sexual/fisiologia , Cloridrato de Vilazodona/farmacologia , Adulto , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Humanos , Masculino , Paroxetina/farmacologia , Inquéritos e Questionários , Resultado do Tratamento
2.
Clin Ther ; 37(9): 2059-70, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26256429

RESUMO

PURPOSE: Levomilnacipran, a selective serotonin (5-HT) and norepinephrine (NE) reuptake inhibitor, is approved for the treatment of major depressive disorder (MDD) in adults. The objectives of this investigation were to characterize the pharmacokinetic (PK) parameters of levomilnacipran in healthy subjects and in patients with MDD and to compare the plasma concentrations observed at clinically effective doses (40-120 mg daily) in MDD patients versus in vitro inhibitory concentration values for NE and 5-HT transporters. METHODS: Data from 2 trials were analyzed: a Phase I trial (healthy volunteers received a single dose of levomilnacipran extended-release capsule [ER; 25, 50, or 100 mg], escalating multiple doses of levomilnacipran ER [25-300 mg once daily], or placebo); and a Phase III trial (adults with MDD received a fixed dose of levomilnacipran ER [40, 80, or 120 mg once daily for 8 weeks]). Plasma samples of participants were assayed to determine levomilnacipran concentrations, and PK analyses were performed. Unbound plasma concentrations of levomilnacipran in MDD patients were estimated, and inhibitory concentration values were determined by curve fitting of the in vitro data. FINDINGS: Cmax and AUC were dose proportional after single dosing (25-100 mg) and multiple dosing (across the 25-300 mg dose range) of levomilnacipran ER in healthy subjects. Dose-proportional steady-state Cmax (93, 180, and 297 ng/mL) and AUC0-τ (1520, 2935, and 4799 ng*h/mL) were also observed in patients with MDD who received levomilnacipran ER (40, 80, and 120 mg daily). Tmax was ~6 hours and was similar after single and multiple oral doses of levomilnacipran ER. Estimates of levomilnacipran concentration at 50%, 80%, and 90% inhibition were 19, 91, and 237 nM, respectively, for the 5-HT transporter, and 10, 41, and 92 nM for the NE transporter. Average unbound plasma concentrations for levomilnacipran in MDD patients treated with levomilnacipran ER 40, 80, or 120 mg daily exceeded the estimated concentration at 80% and 90% inhibition for 5-HT and NE. IMPLICATIONS: Levomilnacipran PK was dose proportional after single and multiple dosing and was similar between healthy subjects and patients with MDD. Steady-state unbound plasma concentrations of levomilnacipran across the approved dose range (40, 80, and 120 mg daily) in MDD patients were estimated to be comparable or greater than the concentrations that inhibited reuptake of NE and 5-HT by >90% and >80%, respectively, in vitro.


Assuntos
Ciclopropanos/farmacocinética , Transtorno Depressivo Maior/tratamento farmacológico , Inibidores Seletivos de Recaptação de Serotonina/farmacocinética , Adulto , Área Sob a Curva , Ciclopropanos/administração & dosagem , Ciclopropanos/sangue , Preparações de Ação Retardada/farmacocinética , Método Duplo-Cego , Feminino , Voluntários Saudáveis , Humanos , Masculino , Milnaciprano , Proteínas da Membrana Plasmática de Transporte de Norepinefrina/efeitos dos fármacos , Proteínas da Membrana Plasmática de Transporte de Serotonina/efeitos dos fármacos , Inibidores Seletivos de Recaptação de Serotonina/administração & dosagem , Inibidores Seletivos de Recaptação de Serotonina/sangue
3.
Clin Drug Investig ; 35(10): 601-12, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26315684

RESUMO

BACKGROUND AND OBJECTIVES: Levomilnacipran is a serotonin and norepinephrine reuptake inhibitor with balanced potency for the reuptake inhibition of norepinephrine and serotonin, approved in the USA for the treatment of major depressive disorder (MDD) in adults. We conducted studies in healthy human subjects to investigate pharmacokinetic interactions when levomilnacipran extended-release (ER) is administered in combination with an inhibitor (ketoconazole), an inducer (carbamazepine), or a substrate (alprazolam) of cytochrome P450 (CYP) 3A4. METHODS: Randomised, open-label studies were conducted in healthy volunteers (n = 34 ketoconazole, n = 34 carbamazepine, n = 30 alprazolam) and pharmacokinetic parameters were determined when levomilnacipran was administered alone or together with the relevant study drug. RESULTS: Co-administration of ketoconazole with levomilnacipran ER increased levomilnacipran maximum concentration (C max) by 39% [90% confidence interval (CI) 31-47%] and area under the concentration-time curve (AUC) by 57% (90% CI 47-67%), whereas carbamazepine reduced the C max and AUC of levomilnacipran by 26% (90% CI 22-30%) and 29% (90% CI 26-32%), respectively. Levomilnacipran at steady state had no significant effect on the pharmacokinetics of a single 1 mg dose of alprazolam extended release (XR); neither did single-dose alprazolam XR affect the steady-state pharmacokinetics of levomilnacipran. No new safety concerns were noted in these studies. CONCLUSIONS: Based on these results, the levomilnacipran ER dose should not exceed 80 mg once daily when used with ketoconazole, compared to 120 mg once daily in the absence of ketoconazole. No dose adjustment for levomilnacipran is suggested when levomilnacipran ER is co-administered with carbamazepine or other CYP3A4 inducers. Co-administration with levomilnacipran of drugs metabolised by CYP3A4, such as alprazolam, requires no dose adjustment due to pharmacokinetic considerations.


Assuntos
Alprazolam/farmacologia , Carbamazepina/farmacologia , Ciclopropanos/farmacocinética , Indutores do Citocromo P-450 CYP3A/farmacologia , Inibidores do Citocromo P-450 CYP3A/farmacologia , Cetoconazol/farmacologia , Adolescente , Adulto , Alprazolam/administração & dosagem , Alprazolam/farmacocinética , Área Sob a Curva , Carbamazepina/administração & dosagem , Ciclopropanos/administração & dosagem , Ciclopropanos/farmacologia , Indutores do Citocromo P-450 CYP3A/administração & dosagem , Inibidores do Citocromo P-450 CYP3A/administração & dosagem , Preparações de Ação Retardada/farmacocinética , Interações Medicamentosas , Feminino , Voluntários Saudáveis , Humanos , Cetoconazol/administração & dosagem , Masculino , Pessoa de Meia-Idade , Milnaciprano , Adulto Jovem
4.
Drug Des Devel Ther ; 9: 3199-215, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26150694

RESUMO

Levomilnacipran is approved in the US for the treatment of major depressive disorder in adults. We characterized the metabolic profile of levomilnacipran in humans, monkeys, and rats after oral administration of [(14)C]-levomilnacipran. In vitro binding of levomilnacipran to human plasma proteins was also studied. Unchanged levomilnacipran was the major circulating compound after dosing in all species. Within 12 hours of dosing in humans, levomilnacipran accounted for 52.9% of total plasma radioactivity; the circulating metabolites N-desethyl levomilnacipran N-carbamoyl glucuronide, N-desethyl levomilnacipran, and levomilnacipran N-carbamoyl glucuronide accounted for 11.3%, 7.5%, and 5.6%, respectively. Similar results were seen in monkeys. N-Desethyl levomilnacipran and p-hydroxy levomilnacipran were the main circulating metabolites in rats. Mass balance results indicated that renal excretion was the major route of elimination with 58.4%, 35.5%, and 40.2% of total radioactivity being excreted as unchanged levomilnacipran in humans, monkeys, and rats, respectively. N-Desethyl levomilnacipran was detected in human, monkey, and rat urine (18.2%, 12.4%, and 7.9% of administered dose, respectively). Human and monkey urine contained measurable quantities of levomilnacipran glucuronide (3.8% and 4.1% of administered dose, respectively) and N-desethyl levomilnacipran glucuronide (3.2% and 2.3% of administered dose, respectively); these metabolites were not detected in rat urine. The metabolites p-hydroxy levomilnacipran and p-hydroxy levomilnacipran glucuronide were detected in human urine (≤ 1.2% of administered dose), and p-hydroxy levomilnacipran glucuronide was found in rat urine (4% of administered dose). None of the metabolites were pharmacologically active. Levomilnacipran was widely distributed with low plasma protein binding (22%).


Assuntos
Antidepressivos/farmacocinética , Ciclopropanos/farmacocinética , Inibidores da Recaptação de Serotonina e Norepinefrina/farmacocinética , Administração Oral , Adolescente , Adulto , Animais , Antidepressivos/administração & dosagem , Antidepressivos/sangue , Antidepressivos/urina , Biotransformação , Radioisótopos de Carbono , Ciclopropanos/administração & dosagem , Ciclopropanos/sangue , Ciclopropanos/urina , Remoção de Radical Alquila , Feminino , Glucuronídeos/farmacocinética , Humanos , Hidroxilação , Macaca fascicularis , Masculino , Pessoa de Meia-Idade , Milnaciprano , Modelos Biológicos , Ligação Proteica , Ratos Sprague-Dawley , Eliminação Renal , Inibidores da Recaptação de Serotonina e Norepinefrina/administração & dosagem , Inibidores da Recaptação de Serotonina e Norepinefrina/sangue , Inibidores da Recaptação de Serotonina e Norepinefrina/urina , Especificidade da Espécie , Distribuição Tecidual , Adulto Jovem
5.
Drug Des Devel Ther ; 9: 3293-300, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26150701

RESUMO

PURPOSE: Levomilnacipran extended-release (ER) is indicated for treatment of major depressive disorder in adults. We evaluated the pharmacokinetic and safety profile of levomilnacipran ER in individuals with impaired renal function. METHODS: A total of 32 individuals participated in four groups (eight in each group) with normal, mild, moderately, or severely impaired renal function. Each participant received one dose of levomilnacipran ER 40 mg. Blood and urine were assayed using liquid chromatography/tandem mass spectrometry. Results between normal and renally impaired groups were compared using analysis of variance. Safety measures included adverse events, laboratory evaluations, vital signs, suicidality, and electrocardiograms. RESULTS: Following administration of levomilnacipran, mean (standard deviation) maximum plasma concentration in participants with normal renal function, and mild, moderate, or severe renal impairment was 83.9 (21.0), 81.8 (23.4), 98.7 (18.1), and 122.1 (35.1) (ng/mL), respectively; area under the curve from time zero to infinity was 2,101.0 (516.9), 2,587.8 (649.9), 4,016.4 (995.4), and 5,900.8 (1,799.3) (h · ng/mL), respectively; terminal elimination half-life was 13.5 (2.8), 17.3 (3.5), 19.1 (4.6), and 27.7 (7.4) (hours), respectively; and renal clearance was 175.9 mL/min, 114.7 mL/min, 69.9 mL/min, and 28.6 mL/min, respectively. Levomilnacipran ER was generally well tolerated with no safety issues of concern identified. CONCLUSION: Renal impairment was associated with increased plasma levels of levomilnacipran and prolonged half-life. No dose adjustment is required for individuals with mild renal impairment; the recommended maximum daily maintenance dose of levomilnacipran ER should not exceed 80 mg for individuals with moderate renal impairment and 40 mg for individuals with severe renal impairment.


Assuntos
Antidepressivos/administração & dosagem , Antidepressivos/farmacocinética , Ciclopropanos/administração & dosagem , Ciclopropanos/farmacocinética , Nefropatias/metabolismo , Rim/metabolismo , Inibidores da Recaptação de Serotonina e Norepinefrina/administração & dosagem , Inibidores da Recaptação de Serotonina e Norepinefrina/farmacocinética , Administração Oral , Adulto , Idoso , Antidepressivos/efeitos adversos , Antidepressivos/sangue , Área Sob a Curva , Química Farmacêutica , Cromatografia Líquida , Ciclopropanos/efeitos adversos , Ciclopropanos/sangue , Preparações de Ação Retardada , Feminino , Meia-Vida , Humanos , Rim/fisiopatologia , Nefropatias/diagnóstico , Nefropatias/fisiopatologia , Masculino , Taxa de Depuração Metabólica , Pessoa de Meia-Idade , Milnaciprano , Eliminação Renal , Inibidores da Recaptação de Serotonina e Norepinefrina/efeitos adversos , Inibidores da Recaptação de Serotonina e Norepinefrina/sangue , Índice de Gravidade de Doença , Espectrometria de Massas em Tandem , Estados Unidos
6.
Clin Drug Investig ; 35(7): 427-35, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26016820

RESUMO

BACKGROUND: Combining two standard-of-care medications for Alzheimer's disease (AD) into a single once-daily dosage unit may improve treatment adherence, facilitate drug administration, and reduce caregiver burden. A new fixed-dose combination (FDC) capsule containing 28 mg memantine extended release (ER) and 10 mg donepezil was evaluated for bioequivalence with co-administered commercially available memantine ER and donepezil, and for bioavailability with regard to food intake. METHODS: Two phase I, single-dose, randomized, open-label, crossover studies were conducted in 18- to 45-year-old healthy individuals. In MDX-PK-104 study, fasting participants (N = 38) received co-administered memantine ER and donepezil or the FDC. In MDX-PK-105 study, participants (N = 36) received three treatments: intact FDC taken while fasting or after a high-fat meal, or FDC contents sprinkled on applesauce while fasting. Standard pharmacokinetic parameters for memantine and donepezil were calculated from the plasma concentration time-curve using non-compartmental analyses. Linear mixed-effects models were used to compare: (a) FDC versus co-administered individual drugs; (b) FDC fasted versus with food; and (c) FDC sprinkled on applesauce versus FDC intact, both fasted. Safety parameters were also evaluated. RESULTS: The FDC capsule was bioequivalent to co-administered memantine ER and donepezil. There was no significant food effect on the bioavailability of the FDC components. There were no clinically relevant differences in time to maximum plasma concentration or safety profiles across treatments. CONCLUSIONS: An FDC capsule containing 28 mg memantine ER and 10 mg donepezil is bioequivalent to commercially available memantine ER and donepezil, and bioavailability is not affected by food intake or sprinkling of capsule contents on applesauce.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Indanos/administração & dosagem , Memantina/administração & dosagem , Piperidinas/administração & dosagem , Adulto , Disponibilidade Biológica , Estudos Cross-Over , Donepezila , Quimioterapia Combinada , Feminino , Voluntários Saudáveis , Humanos , Indanos/efeitos adversos , Indanos/farmacocinética , Masculino , Memantina/efeitos adversos , Memantina/farmacocinética , Piperidinas/efeitos adversos , Piperidinas/farmacocinética
7.
Clin Drug Investig ; 34(5): 351-9, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24677141

RESUMO

BACKGROUND AND OBJECTIVES: Levomilnacipran is a serotonin and norepinephrine reuptake inhibitor with greater potency for the reuptake inhibition of norepinephrine than of serotonin, approved in the USA for the treatment of major depressive disorder (MDD) in adults. METHODS: A single-dose, open-label, parallel-group study was conducted to evaluate the effects of hepatic impairment on the pharmacokinetics of levomilnacipran in adults with mild, moderate, or severe hepatic impairment and normal controls receiving a 40 mg levomilnacipran extended-release (ER) capsule. The concentrations of levomilnacipran and its inactive metabolite, N-desethyl levomilnacipran, in plasma and urine were measured using liquid chromatography-tandem mass spectrometry methods. Pharmacokinetic parameters of levomilnacipran and N-desethyl levomilnacipran were derived and assessed. Safety parameters were assessed throughout the trial. RESULTS: No deaths, serious adverse events, or discontinuations due to adverse events occurred. The maximum plasma drug concentration (C(max)) and area under the plasma concentration-time curve from time zero to infinity (AUC(∞)) of levomilnacipran were 28 and 32 % higher, respectively, in participants with severe hepatic impairment than in healthy participants without a notable change in the terminal elimination half-life, whereas the C(max) and AUC(∞) of N-desethyl levomilnacipran were 66 and 85 % lower, respectively, suggesting liver function has minimal impact on the overall exposure of levomilnacipran but plays a significant role in the formation of the metabolite. CONCLUSIONS: A single dose of levomilnacipran ER 40 mg was generally well-tolerated in participants with varying degrees of hepatic impairment and healthy controls. Therefore, dose adjustment for levomilnacipran is not necessary in adult MDD patients with impaired liver function.


Assuntos
Ciclopropanos/administração & dosagem , Ciclopropanos/farmacocinética , Hepatopatias/fisiopatologia , Administração Oral , Adolescente , Adulto , Idoso , Cápsulas , Estudos de Casos e Controles , Preparações de Ação Retardada , Relação Dose-Resposta a Droga , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Milnaciprano , Adulto Jovem
8.
Bioorg Med Chem Lett ; 21(23): 7006-12, 2011 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-22018461

RESUMO

The synthesis, structure-activity relationships (SAR), and biological results of pyridyl-substituted azaindole based tricyclic inhibitors of IKK2 are described. Compound 4m demonstrated potent in vitro potency, acceptable pharmacokinetic and physicochemical properties, and efficacy when dosed orally in a mouse model of inflammatory bowel disease.


Assuntos
Acetamidas/química , Descoberta de Drogas , Inibidores Enzimáticos/química , Compostos Heterocíclicos com 3 Anéis/química , Quinase I-kappa B/antagonistas & inibidores , Acetamidas/síntese química , Acetamidas/farmacologia , Administração Oral , Animais , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Compostos Heterocíclicos com 3 Anéis/síntese química , Compostos Heterocíclicos com 3 Anéis/farmacologia , Humanos , Doenças Inflamatórias Intestinais/tratamento farmacológico , Concentração Inibidora 50 , Camundongos , Estrutura Molecular , Ratos , Relação Estrutura-Atividade
10.
J Pharmacol Exp Ther ; 331(2): 349-60, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19652024

RESUMO

We have previously shown that inhibitors of IkappaB kinase beta (IKKbeta), including 4(2'-aminoethyl)amino-1,8-dimethylimidazo(1,2-a)quinoxaline (BMS-345541), are efficacious against experimental arthritis in rodents. In our efforts to identify an analog as a clinical candidate for the treatment of autoimmune and inflammatory disorders, we have discovered the potent and highly selective IKKbeta inhibitor 2-methoxy-N-((6-(1-methyl-4-(methylamino)-1,6-dihydroimidazo[4,5-d]pyrrolo[2,3-b]pyridin-7-yl)pyridin-2-yl)methyl)acetamide (BMS-066). Investigations of its pharmacology in rodent models of experimental arthritis showed that BMS-066 at doses of 5 and 10 mg/kg once daily was effective at protecting rats against adjuvant-induced arthritis, despite showing only weak inhibition at 10 mg/kg against a pharmacodymanic model of tumor necrosis factor alpha production in rats challenged with lipopolysaccharide. The duration of exposure in rats indicated that just 6 to 9 h of coverage per day of the concentration necessary to inhibit IKKbeta by 50% in vivo was necessary for protection against arthritis. Similar findings were observed in the mouse collagen-induced arthritis model, with efficacy observed at a dose providing only 6 h of coverage per day of the concentration necessary to inhibit IKKbeta by 50%. This finding probably results from the cumulative effect on multiple cellular mechanisms that contribute to autoimmunity and joint destruction, because BMS-066 was shown to inhibit a broad spectrum of activities such as T cell proliferation, B cell function, cytokine and interleukin secretion from monocytes, T(H)17 cell function and regulation, and osteoclastogenesis. Thus, only partial and transient inhibition of IKKbeta is sufficient to yield dramatic benefit in vivo, and this understanding will be important in the clinical development of IKKbeta inhibitors.


Assuntos
Acetamidas/farmacologia , Artrite Reumatoide/tratamento farmacológico , Compostos Heterocíclicos com 3 Anéis/farmacologia , Quinase I-kappa B/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Transdução de Sinais/efeitos dos fármacos , Acetamidas/farmacocinética , Acetamidas/uso terapêutico , Animais , Artrite Experimental/induzido quimicamente , Artrite Experimental/tratamento farmacológico , Artrite Experimental/patologia , Artrite Reumatoide/induzido quimicamente , Artrite Reumatoide/patologia , Autoimunidade/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Colágeno , Compostos Heterocíclicos com 3 Anéis/farmacocinética , Compostos Heterocíclicos com 3 Anéis/uso terapêutico , Humanos , Proteínas I-kappa B/metabolismo , Imunoglobulinas/biossíntese , Técnicas In Vitro , Articulações/patologia , Células Jurkat , Lipopolissacarídeos , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Monócitos/efeitos dos fármacos , Osteoclastos/efeitos dos fármacos , Ligação Proteica , Ratos , Ratos Endogâmicos Lew , Fator de Necrose Tumoral alfa/biossíntese
12.
J Med Chem ; 52(7): 1994-2005, 2009 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-19267461

RESUMO

The design and synthesis of a novel series of oxazole-, thiazole-, and imidazole-based inhibitors of IkappaB kinase (IKK) are reported. Biological activity was improved compared to the pyrazolopurine lead, and the expedient synthesis of the new tricyclic systems allowed for efficient exploration of structure-activity relationships. This, combined with an iterative rat cassette dosing strategy, was used to identify compounds with improved pharmacokinetic (PK) profiles to advance for in vivo evaluation.


Assuntos
Compostos Heterocíclicos com 3 Anéis/síntese química , Quinase I-kappa B/antagonistas & inibidores , Imidazóis/síntese química , Oxazóis/síntese química , Tiazóis/síntese química , Animais , Cristalografia por Raios X , Feminino , Glutationa Transferase/genética , Glutationa Transferase/metabolismo , Compostos Heterocíclicos com 3 Anéis/farmacocinética , Compostos Heterocíclicos com 3 Anéis/farmacologia , Humanos , Quinase I-kappa B/genética , Imidazóis/farmacocinética , Imidazóis/farmacologia , Técnicas In Vitro , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/metabolismo , Lipopolissacarídeos/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Microssomos Hepáticos/metabolismo , Oxazóis/farmacocinética , Oxazóis/farmacologia , Ratos , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Relação Estrutura-Atividade , Tiazóis/farmacocinética , Tiazóis/farmacologia , Fator de Necrose Tumoral alfa/biossíntese
13.
Rapid Commun Mass Spectrom ; 20(1): 39-47, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16308873

RESUMO

Fluoxetine (F) and its active N-demethylated metabolite, norfluoxetine (NF), are selective serotonin re-uptake inhibitors that bind extensively to plasma proteins. Development and validation of a novel method for measuring free concentrations of F and NF in plasma are reported here. The plasma filtrate was prepared by a high-speed short-duration ultrafiltration (UF) and then submitted directly to a short-column liquid chromatography/tandem mass spectrometric (LC/MS/MS) assay. There was no significant matrix effect on the analysis, and non-specific binding of the analytes to the UF devices was negligible. For validation of the method, the recovery of the free analytes was compared to that from an optimized equilibrium dialysis method, and analyte stability was examined under conditions mimicking the sample storage, handling, and analysis procedures. The linearity range was 0.37-12 ng/mL for F and NF; the within-run and between-run relative standard deviations were less than 11.9%, and accuracies across the assay range were 100 +/- 10.3%. This new method was then further validated in a pharmacokinetic (PK) study in beagle dogs receiving a single oral dose of fluoxetine hydrochloride. The integrity of the resulting PK data of free F and NF was absolute. The PK data indicate that the novel method is accurate and reliable. To our knowledge this is the first report describing a rapid and reliable method for direct measurement of free concentrations of F and NF in plasma, which will be useful for clinical pharmacokinetic/pharmacodynamic studies of F. Furthermore, the strategies described herein may be applied to the development and validation of methods for measuring the free concentrations of other drugs in plasma.


Assuntos
Fluoxetina/análogos & derivados , Fluoxetina/sangue , Fluoxetina/metabolismo , Animais , Cães , Fluoxetina/química , Fluoxetina/farmacocinética , Masculino , Ligação Proteica , Fatores de Tempo
14.
Cancer Epidemiol Biomarkers Prev ; 11(10 Pt 1): 1025-32, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12376503

RESUMO

Green tea and tea polyphenols have been studied extensively as cancer chemopreventive agents in recent years. The bioavailability and metabolic fate of tea polyphenols in humans, however, are not clearly understood. In this report, the pharmacokinetic parameters of (-)-epigallocatechin-3-gallate (EGCG), (-)-epigallocatechin (EGC), and (-)-epicatechin (EC) were analyzed after administration of a single oral dose of green tea or decaffeinated green tea (20 mg tea solids/kg) or EGCG (2 mg/kg) to eight subjects. The plasma and urine levels of total EGCG, EGC, and EC (free plus conjugated forms) were quantified by HPLC coupled to an electrochemical detector. The plasma concentration time curves of the catechins were fitted in a one-compartment model. The maximum plasma concentrations of EGCG, EGC, and EC in the three repeated experiments with green tea were 77.9 +/- 22.2, 223.4 +/- 35.2, and 124.03 +/- 7.86 ng/ml, respectively, and the corresponding AUC values were 508.2 +/- 227, 945.4 +/- 438.4, and 529.5 +/- 244.4 ng x h x ml(-1), respectively. The time needed to reach the peak concentrations was in the range of 1.3-1.6 h. The elimination half-lives were 3.4 +/- 0.3, 1.7 +/- 0.4, and 2.0 +/- 0.4 h, respectively. Considerable interindividual differences and variations between repeated experiments in the pharmacokinetic parameters were noted. Significant differences in these pharmacokinetic parameters were not observed when EGCG was given in decaffeinated green tea or in pure form. In the plasma, EGCG was mostly present in the free form, whereas EGC and EC were mostly in the conjugated form. Over 90% of the total urinary EGC and EC, almost all in the conjugated forms, were excreted between 0 and 8 h. Substantial amounts of 4'-O-methyl EGC, at levels higher than EGC, were detected in the urine and plasma. The plasma level of 4'-O-methyl EGC peaked at 1.7 +/- 0.5 h with a half life of 4.4 +/- 1.1 h. Two ring-fission metabolites, (-)-5-(3',4',5'-trihydroxyphenyl)-gamma-valerolactone (M4) and (-)-5-(3',4'-dihydroxyphenyl)-valerolactone (M6), appeared in significant amounts after 3 h and peaked at 8-15 h in the urine as well as in the plasma. These results may be useful for designing the dose and dose frequency in intervention studies with tea and for development of biomarkers of tea consumption.


Assuntos
Antioxidantes/farmacocinética , Catequina/análogos & derivados , Catequina/farmacocinética , Chá , Ativador de Plasminogênio Tipo Uroquinase/antagonistas & inibidores , Administração Oral , Adulto , Disponibilidade Biológica , Biomarcadores/análise , Cromatografia Líquida de Alta Pressão , Feminino , Meia-Vida , Humanos , Masculino , Reprodutibilidade dos Testes
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA