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1.
Eur J Neurol ; 18(4): 631-6, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20860754

RESUMO

BACKGROUND: Early occurrence of small-fibre neuropathy (SFN) is a common feature of Fabry disease (FD) - an X-linked storage disorder caused by reduced activity of the α-galactosidase A (α-GAL). Although SFN may result from different disorders, the cause is often unclear. Therefore, we investigated the frequency of FD in patients with SFN of unknown aetiology. METHODS: Patients with idiopathic SFN, established by sensory quantitative testing and/or skin biopsy, were examined for mutations in the α-GAL gene. Where mutations in the α-GAL gene were identified, levels of globotriaosylceramide (Gb(3)) were measured in urine and blood and the α-GAL activity was evaluated. When new mutations were detected, a diagnostic work-up was performed as well as a Gb(3) accumulation in the skin, lyso-Gb(3) in blood and Gb(3)_24 in urine were proved. RESULTS: Twenty-four of 29 eligible patients were enrolled in the study. Mutations in the α-GAL gene were observed in five patients. A typical mutation for FD (c.424T>C, [C142R]) was detected in one patient. In four patients, a complex intronic haplotype within the α-GAL gene (IVS0-10C>T [rs2071225], IVS4-16A>G [rs2071397], IVS6-22C>T [rs2071228]) was identified. The relevance of this haplotype in the pathogenesis of FD remains unclear until now. However, these patients showed increased concentrations of Gb(3) and/or lyso-Gb(3), while no further manifestations for FD could be proved. CONCLUSIONS: Fabry disease should be considered in patients with SFN of unknown aetiology, and screening for FD should be included in the diagnostic guidelines for SFN. The significance of the intronic haplotype regarding SFN needs further evaluation.


Assuntos
Doença de Fabry/complicações , Doença de Fabry/epidemiologia , Polineuropatias/genética , Adulto , Idoso , Análise Mutacional de DNA , Doença de Fabry/genética , Feminino , Humanos , Imuno-Histoquímica , Masculino , Espectrometria de Massas , Pessoa de Meia-Idade , Mutação , Projetos Piloto , alfa-Galactosidase/análise , alfa-Galactosidase/genética
2.
Clin Pharmacol Ther ; 62(3): 293-9, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9333105

RESUMO

INTRODUCTION: To date it is unclear whether therapeutic concentrations are attained in target tissues after topical administration of nonsteroidal anti-inflammatory drugs. Therefore this study in healthy volunteers was undertaken to measure diclofenac concentrations attained in defined tissue layers directly underlying the site of topical diclofenac application by in vivo microdialysis. METHODS: In each experiment two microdialysis probes were inserted, one into a superficial (3.9 +/- 0.3 mm) and one into a deep (9.3 +/- 0.5 mm) tissue layer, in 20 healthy volunteers and calibrated in vivo. The distance between the surface of the skin and the tips of the microdialysis probes was measured by 7.5 MHz ultrasound. Diclofenac was administered topically as a single dose of approximately 300 mg/100 cm2. Concentration versus time profiles in tissue layers were monitored for 5 hours. RESULTS: Concentration versus time profiles were obtained in 11 of 20 experiments. However, there was no correlation between area under the concentration-time curve (AUC) in a defined layer and the depth of probe insertion. In those experiments where concentration versus time profiles were obtained for both probes mean AUC was 532 +/- 197 microg x min x ml(-1) for superficial layers, and 438 +/- 249 microg x min x ml(-1) for deep layers. CONCLUSION: We conclude that transdermal penetration of diclofenac, at least after single doses, is not predictable and may strongly be influenced by individual skin properties.


Assuntos
Anti-Inflamatórios não Esteroides/farmacocinética , Diclofenaco/farmacocinética , Microdiálise/métodos , Pele/metabolismo , Administração Cutânea , Adulto , Anti-Inflamatórios não Esteroides/administração & dosagem , Área Sob a Curva , Calibragem , Diclofenaco/administração & dosagem , Relação Dose-Resposta a Droga , Humanos , Técnicas In Vitro , Masculino , Absorção Cutânea/fisiologia , Distribuição Tecidual
3.
Neurology ; 43(2): 421-4, 1993 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8437713

RESUMO

A 10-week-old girl with nonketotic hyperglycinemia was treated with increasing amounts of dextromethorphan, an NMDA receptor antagonist. She improved neurologically; at 35 mg/kg/d, seizures ceased and EEG normalized. Dextromethorphan withdrawal resulted in a dramatic clinical deterioration coinciding with epileptic and high-voltage slow activity in the EEG. After reintroduction of dextromethorphan (35 mg/kg/d), recovery occurred within 24 hours.


Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/tratamento farmacológico , Dextrometorfano/uso terapêutico , Eletroencefalografia/efeitos dos fármacos , Glicina/sangue , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Erros Inatos do Metabolismo dos Aminoácidos/metabolismo , Erros Inatos do Metabolismo dos Aminoácidos/fisiopatologia , Dextrometorfano/farmacocinética , Feminino , Glicina/metabolismo , Humanos , Lactente
4.
Eur J Cancer ; 30A(9): 1250-4, 1994.
Artigo em Inglês | MEDLINE | ID: mdl-7999407

RESUMO

51 patients with metastatic colorectal cancer (stage Dukes D) were treated with intravenous (i.v.) infusion on days 1, 3, 5, 8 and 16 with folinic acid (200 mg/m2) and 5-fluorouracil (600 mg/m2), and on days 1, 8 and 16 with cisplatinum (25 mg/m2 i.v.); cycles were repeated every 4 weeks. All 51 patients were evaluable for toxicity and response criteria. 26 patients had objective responses (3 complete responses, 5.9%; 23 partial responses, 45.1%), relative risk 51% (95% confidence intervals 36.7-65.0%). Response duration ranged from 4 to 28.0 months (median 16.8). Overall median survival of all patients included was 14.7 months (range 3.0-33.0). Toxicity of WHO grade III, requiring dose reduction, occurred in 9 (18%) patients. The regimen described here appears to be active, safe and well tolerated for treatment of patients with advanced colorectal cancer.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias do Colo/tratamento farmacológico , Neoplasias Retais/tratamento farmacológico , Idoso , Cisplatino/administração & dosagem , Neoplasias do Colo/sangue , Neoplasias do Colo/mortalidade , Feminino , Fluoruracila/administração & dosagem , Fluoruracila/farmacocinética , Humanos , Infusões Intravenosas , Leucovorina/administração & dosagem , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Neoplasias Retais/sangue , Neoplasias Retais/mortalidade , Fatores de Tempo , Resultado do Tratamento
5.
J Chromatogr A ; 812(1-2): 339-42, 1998 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-9691330

RESUMO

A sensitive and specific high-performance liquid chromatographic method was developed and validated for the determination of minocycline in human plasma. The method uses liquid-liquid extraction, reextraction and HPLC with UV detection. The assay shows linearity in the tested range of 28-3533 ng/ml with a limit of quantification of 30 ng/ml. The inter-day precision was found to be +/-3.84 to +/-6.57% (R.S.D.) in the range of 148 to 2743 ng/ml. The method was successfully applied to pharmacokinetic studies.


Assuntos
Antibacterianos/sangue , Minociclina/sangue , Cromatografia Líquida de Alta Pressão , Humanos , Indicadores e Reagentes , Controle de Qualidade , Solventes , Espectrofotometria Ultravioleta
6.
J Chromatogr A ; 812(1-2): 221-6, 1998 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-9691321

RESUMO

A high selective, sensitive and fast HPLC method developed for the determination in human serum and plasma. After protein precipitation with perchloric acid, an aliquot of the supernatant was neutralized by mixing it with sodium acetate solution and injected into a C18 HPLC column. Detection was done by a fluorescence detector after on-line postcolumn derivatisation with fluorescamine. The practical limit of quantification was 0.1 microgram/ml using 0.3 ml of plasma. Linearity was given in the tested range of 0.1 to 15 micrograms/ml plasma. Inter-day precision (relative standard deviation) over 7 days for 0.42 micrograms/ml was +/- 7.27%; for 4.54 micrograms/ml, +/- 5.24% and for 13.18 micrograms/ml, +/- 5.25%. Stability over 50 days in serum and plasma occurs at -70 degrees C but not at -20 degrees C (-25 to -35% reduction). This method was used for thousands of human serum and plasma samples.


Assuntos
Amoxicilina/análise , Amoxicilina/sangue , Amoxicilina/urina , Calibragem , Cromatografia Líquida de Alta Pressão , Fluorescamina , Humanos , Indicadores e Reagentes , Reprodutibilidade dos Testes , Espectrometria de Fluorescência
7.
J Chromatogr A ; 812(1-2): 381-5, 1998 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-9691333

RESUMO

A method for the determination of norfloxacin in human plasma and urine is described. Plasma samples were deproteinized using acetonitrile. The supernatant was analysed by C18 HPLC. Fluorescence detection at an excitation wavelength of 300 nm and an emission wavelength of 450 nm was utilized. The assay was validated in the concentration range of 31 to 2507 ng/ml when 0.5-ml aliquots of plasma were handled. The intra-day precision of the spiked quality control samples ranged from +/- 0.37 to +/- 4.14% in plasma (concentration range: 70.3-2109.2 ng/ml) and from +/- 0.51 to +/- 1.56% in urine (concentration range: 7.5-299.4 micrograms/ml). The intra-day accuracy obtained for norfloxacin in the quality control samples ranged from -5.18% to -9.47% in plasma and from -10.56% to - 5.91% in urine. The assay has been used to support human pharmacokinetic studies.


Assuntos
Anti-Infecciosos/análise , Norfloxacino/análise , Anti-Infecciosos/sangue , Anti-Infecciosos/urina , Cromatografia Líquida de Alta Pressão , Humanos , Indicadores e Reagentes , Norfloxacino/sangue , Norfloxacino/urina , Padrões de Referência , Reprodutibilidade dos Testes , Solventes , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta
8.
J Pharm Sci ; 82(9): 972-4, 1993 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8229700

RESUMO

An HPLC method for determining total pyridoxal from plasma was developed for a relative bioavailability comparison of two oral vitamin B6 (pyridoxine HCl) preparations. After cleavage of the pyridoxal-5-phosphate with the acid phosphatase enzyme, the total pyridoxal was determined by HPLC. Pyridoxal was separated on a reversed-phase column, post-column derivatized to pyridoxal-semicarbazide, and then detected by fluorescence and quantitated. The limit of detection was 2 ng/mL and interday variation (3 days) over the whole concentration range (13-215 ng/mL spiked) was < 4.1%. In the relative bioavailability study, 16 human subjects were put on a low vitamin B6 diet for a period of 3 days. On the 2nd and 3rd days, 14 blood samples were taken per subject at the same times each day. The drug was administered on the 3rd day. Total endogenous pyridoxal detected on the 2nd day varied in plasma between 13 and 17 ng/mL. Pharmacokinetic parameters corrected for background are reported for two vitamin B6 (40 mg) preparations. Briefly, the pharmacokinetic results for the Ratiopharm preparation compared with the Hoffmann-La Roche preparation are, respectively: AUC0-24, 369.2 and 352.6 ng.h/mL; AUC24-48, 1638.2 and 1662.3 ng.h/mL; net Cmax, 193.0 and 197.1 ng/mL; tmax, 1.25 and 1.44 h; and relative bioavailability, 97.9% (Westlake, 88-112%).


Assuntos
Piridoxal/sangue , Piridoxina/farmacocinética , Adulto , Disponibilidade Biológica , Cromatografia Líquida de Alta Pressão , Dieta , Feminino , Humanos , Absorção Intestinal , Masculino , Piridoxal/farmacocinética , Fosfato de Piridoxal/sangue , Semicarbazidas/química , Espectrometria de Fluorescência
9.
J Pharm Sci ; 82(1): 56-9, 1993 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8429493

RESUMO

A high-performance liquid chromatographic method for the determination of total thiamine in plasma was developed for a relative bioavailability comparison of two oral thiamine preparations. After separation of thiamine mono- and diphosphates with the phosphatase enzyme, the total thiamine was subjected to reversed-phase high-performance liquid chromatography, postcolumn oxidized to thiochrome with K3[Fe(CN)6], and detected by fluorescence. In the bioavailability study, 16 human subjects were put on a low-thiamine diet for 3 days. On the 2nd and 3rd days, 14 blood samples per subject and day were taken at the same times each day. Drug administration did not take place until the 3rd day. After deduction of the native concentrations of total thiamine detected on the 2nd day (mean value of approximately 7 ng/mL), the post-treatment pharmacokinetic parameters were determined (two different preparations, each with 200 mg of thiamine.HCl).


Assuntos
Tiamina/sangue , Adulto , Disponibilidade Biológica , Cromatografia Líquida de Alta Pressão , Dieta , Feminino , Humanos , Masculino , Fosfatos/isolamento & purificação , Tiamina/farmacocinética
10.
J Pharm Sci ; 73(11): 1556-8, 1984 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-6520757

RESUMO

A high-performance liquid chromatographic (HPLC) method for the determination of codeine in human plasma is described. The specific, precise, and sensitive method can be used to determine plasma codeine levels after administration of therapeutic doses of codeine. After purification on a C18 extraction column, codeine in the form of hydrochloride is eluted. After addition of the internal standard, the codeine is separated on a reverse-phase C18 column using a slightly alkaline mobile phase and is then determined by UV detection. The analysis takes 3.5 min per run; the limit of detection is approximately 3 micrograms/L for a 50-microL loop and 800 microL of plasma. The absolute recovery is 98.4 +/- 6.7% (n = 14) in the 10-300-micrograms/L range. Within the range, the calibration curve is linear.


Assuntos
Codeína/sangue , Adulto , Disponibilidade Biológica , Cromatografia Líquida de Alta Pressão/métodos , Doxiciclina/metabolismo , Meia-Vida , Humanos , Cinética , Masculino
11.
Int J Clin Pharmacol Ther ; 35(1): 9-13, 1997 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9021435

RESUMO

A bioavailability study of 2 different selegiline preparations were conducted in 20 healthy volunteers to test the bioequivalence. Almost no bioavailability study of selegiline has been published. As plasma levels of selegiline are very low and the elimination half-life is very short being about 9 minutes, therefore, a very sensitive and selective method for determining the 3 main metabolites desmethylselegiline (DMS), methamphetamine (MA) and amphetamine (A) was developed. After application of a single oral dose of 5 mg selegiline the Cmax values of DMS reached 5-6 ng/ml, of MA 6-7 ng/ml and of A about 2 ng/ml. The AUC infinity values were with DMS about 11 ng/ml x h +/- 4.5, with MA about 130 g/ml x h +/- 50 and with A about 50 ng/ml x h +/- 15. The 90% confidence interval was with logarithmic transformed AUC infinity values 92-107% with DMS, 89-107% with MA, and 84-104% with A. The logarithmic transformed Cmax values showed a 90% confidence interval of 92-127% with DMS, 91-101% with MA, and 90-103% with A. All relevant pharmacokinetic parameters showed bioequivalence with all 3 metabolites (DMS, MA, and A).


Assuntos
Anfetamina/farmacocinética , Anfetaminas/farmacocinética , Estimulantes do Sistema Nervoso Central/farmacocinética , Metanfetamina/farmacocinética , Inibidores da Monoaminoxidase/metabolismo , Selegilina/metabolismo , Administração Oral , Adulto , Disponibilidade Biológica , Meia-Vida , Humanos , Masculino , Inibidores da Monoaminoxidase/administração & dosagem , Inibidores da Monoaminoxidase/farmacocinética , Selegilina/administração & dosagem , Selegilina/farmacocinética , Equivalência Terapêutica
12.
Int J Clin Pharmacol Ther ; 36(8): 414-7, 1998 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9726693

RESUMO

The pharmacokinetic properties of 2 film-coated preparations containing 200 mg and 400 mg dexibuprofen were compared in a single-dose, crossover study in 16 healthy, male volunteers. Dexibuprofen was absorbed rapidly (tmax 2.1 - 2.2 hours) reaching maximum concentrations of 12.4 microg/ml (200 mg), respectively 12.0 microg/ml (400 mg dose adjusted). For the characteristics AUC(0-12h) and AUC(0-infinity) arithmetic means of 49.2 (microg) x (h/ml)(200 mg) and 48.2 (microg) x (h/ml)(400 mg dose-adjusted), respectively 50.5 (microg) x (h/ml)(200 mg), and 49.2 (microg) x (h/ml)(400 mg) were calculated. No relevant differences for the pharmacokinetic characteristics terminal half-life, clearance, volume of distribution, and mean residence time were observed. A linear dose-relationship was shown over the investigated dose range. Mean ratios after dosage adjustment of the test preparation using the "2 one-sided t-tests" procedure were calculated. Bioequivalence was assessed for AUC(0-12h) with a mean ratio of 97.7% (90% CI: 92.4 - 103.3%), for AUC(0-infinity) with 97.1% (90% CI: 91.4 - 103.1%), and for Cmax with 97.5% (90% CI: 91.7 - 103.8%). Both dexibuprofen preparations were well tolerated. No changes in hematological and biochemical parameters were detected.


Assuntos
Anti-Inflamatórios não Esteroides/farmacocinética , Ibuprofeno/farmacocinética , Administração Oral , Adulto , Área Sob a Curva , Disponibilidade Biológica , Estudos Cross-Over , Meia-Vida , Humanos , Masculino , Taxa de Depuração Metabólica , Estereoisomerismo , Comprimidos
13.
Int J Clin Pharmacol Ther ; 42(7): 353-9, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15605686

RESUMO

OBJECTIVE: Transdermal penetration of nonsteroidal anti-inflammatory drugs (NSAIDs) has been shown to be highly variable. The present study was performed to gain insight into the transdermal penetration process of topically applied diclofenac and to test whether transdermal absorption leads to pharmacologically effective concentrations in dermal tissue layers beneath the application site. MATERIAL AND METHOD: Six healthy male volunteers participated in this 2-way crossover study and were assigned to 2 treatment groups. In the first group, diclofenac was applied at a therapeutic dose of 60 mg/100 cm2 3 times daily for 4 days with subsequent occlusion with a plastic foil for 4 hours to enhance transdermal drug absorption. After a 1-week wash-out, diclofenac was applied at a single dose of 300 mg/100 cm2 without occlusion. Diclofenac in both groups was applied on a previously shaven area of the thigh. Transdermal penetration was assessed employing in vivo microdialysis. RESULTS: After multiple-dose administration mean diclofenac concentrations of 0.48 +/- 0.35 ng x ml(-1) were observed in subcutaneous tissue (mean +/- SEM). The mean AUC(subcutis/plasma) ratio of 0.08 +/- 0.02 indicates redistribution of diclofenac from the systemic circulation to the tissue. After single-dose treatment, mean tissue concentrations were 24.26 +/- 46.43 ng x ml(-1) with a mean AUC(subcutis/plasma) ratio of 60.85 +/- 57.59, which suggests direct tissue penetration of diclofenac. CONCLUSIONS: Transdermal penetration of diclofenac after multiple as well as after single application of the present formulation is highly variable. In addition to other factors influencing the transdermal penetration process, dose and mode of administration are important factors determining whether pharmacologically effective local tissue concentrations are attained.


Assuntos
Anti-Inflamatórios não Esteroides/farmacocinética , Diclofenaco/farmacocinética , Absorção Cutânea , Administração Cutânea , Adulto , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/sangue , Estudos Cross-Over , Diclofenaco/administração & dosagem , Diclofenaco/sangue , Relação Dose-Resposta a Droga , Esquema de Medicação , Emulsões , Géis , Humanos , Masculino , Microdiálise , Fatores de Tempo
14.
Int J Clin Pharmacol Ther ; 34(1 Suppl): S76-80, 1996 May.
Artigo em Inglês | MEDLINE | ID: mdl-8793607

RESUMO

The new H+/K+ ATPase inhibitor pantoprazole is extensively metabolized by the liver. As substituted benzimidazoles may potentially interact with the cytochrome P450 system, the influence of pantoprazole on the pharmacokinetics of the NSAID diclofenac was investigated. Diclofenac is widely used in the treatment of rheumatic diseases and is mainly metabolized in the liver by CYP2C9. Twenty-four healthy volunteers (13 male/11 female) completed a randomized crossover study. As test they received orally 40 mg pantoprazole and concomitantly 100 mg diclofenac. As respective references 100 mg diclofenac or 40 mg pantoprazole were given alone. Diclofenac and pantoprazole serum concentrations were measured. Lack of pharmacokinetic interaction was handled as an equivalence problem. The 90% confidence intervals (CI) of the ratios of the primary characteristic AUC and the secondary characteristic Cmax of diclofenac were entirely within the equivalence range of 0.8-1.25. Hence, no influence of pantoprazole on the pharmacokinetics of diclofenac was concluded, either by competition with the CYP2C9 or by the reduction of gastric acid secretion. Vice versa, diclofenac did not affect the pharmacokinetics of pantoprazole. All treatments were safe and well tolerated. No dose adjustment is required during concomitant treatment with diclofenac and pantoprazole.


Assuntos
Anti-Inflamatórios não Esteroides/farmacocinética , Antiulcerosos/farmacologia , Anticonvulsivantes/farmacocinética , Benzimidazóis/farmacologia , Diclofenaco/farmacocinética , Inibidores Enzimáticos/farmacologia , Inibidores da Bomba de Prótons , Sulfóxidos/farmacologia , 2-Piridinilmetilsulfinilbenzimidazóis , Adulto , Anti-Inflamatórios não Esteroides/farmacologia , Antiulcerosos/farmacocinética , Anticonvulsivantes/efeitos adversos , Área Sob a Curva , Benzimidazóis/farmacocinética , Estudos Cross-Over , Diclofenaco/farmacologia , Método Duplo-Cego , Interações Medicamentosas , Inibidores Enzimáticos/farmacocinética , Feminino , Meia-Vida , Humanos , Masculino , Omeprazol/análogos & derivados , Pantoprazol , Sulfóxidos/farmacocinética
15.
Int J Clin Pharmacol Ther ; 34(4): 152-6, 1996 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8861733

RESUMO

The new H+/K+ ATPase inhibitor pantoprazole is extensively metabolized by the liver. As substituted benzimidazoles may potentially interact with the cytochrome P450 system, the influence of pantoprazole on the pharmacokinetics of the NSAID diclofenac was investigated. Diclofenac is widely used in the treatment of rheumatic diseases and is mainly metabolized in the liver by CYP2C9. Twenty-four healthy volunteers (13 male/11 female) completed a randomized crossover study. As test they received orally 40 mg pantoprazole and concomitantly 100 mg diclofenac. As respective references 100 mg diclofenac or 40 mg pantoprazole were given alone. Diclofenac and pantoprazole serum concentrations were measured. Lack of pharmacokinetic interaction was handled as an equivalence problem. The 90% confidence intervals (CI) of the ratios of the primary characteristic AUC and the secondary characteristic C(max) of diclofenac were entirely within the equivalence range of 0.8 - 1.25. Hence, no influence of pantoprazole on the pharmacokinetics of diclofenac was concluded, either by competition with the CYP2C9 or by the reduction of gastric acid secretion. Vice versa, diclofenac did not affect the pharmacokinetics of pantoprazole. All treatments were safe and well tolerated. No dose adjustment is required during concomitant treatment with diclofenac and pantoprazole.


Assuntos
Anti-Inflamatórios não Esteroides/farmacocinética , Benzimidazóis/farmacologia , Diclofenaco/farmacocinética , Inibidores Enzimáticos/farmacologia , Sulfóxidos/farmacologia , 2-Piridinilmetilsulfinilbenzimidazóis , Administração Oral , Adulto , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/sangue , Área Sob a Curva , Benzimidazóis/sangue , Disponibilidade Biológica , Pressão Sanguínea/efeitos dos fármacos , Diclofenaco/administração & dosagem , Diclofenaco/sangue , Interações Medicamentosas , Inibidores Enzimáticos/sangue , Feminino , Humanos , Masculino , Omeprazol/análogos & derivados , Pantoprazol , Distribuição Aleatória , Sulfóxidos/sangue
16.
Int J Clin Pharmacol Ther ; 34(10): 420-3, 1996 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8897078

RESUMO

The new H+/K+ ATPase inhibitor pantoprazole, a substituted benzimidazole, is metabolized by the hepatic cytochrome P450 enzymes 2C19 or 3A4 and subsequently undergoes phase II metabolism. The widely used beta 1-adrenoreceptor-blocking agent metoprolol is metabolized via CYP2D6. The influence of pantoprazole on the pharmacokinetics of an orally administered zero order kinetics formulation (ZOK) of metoprolol was the objective of this study. Eighteen volunteers (9 female, 9 male, age 20-44 years) completed the randomized, double-blind crossover study. Each subject received either 95 mg metoprolol and placebo (reference (R)) or 95 mg metoprolol and 40 mg pantoprazole (test (T)) as oral doses (sid) for 5 consecutive days. On day 5 of each period serum concentrations of R- and S-metoprolol were determined and a treadmill ergometry was performed. The primary pharmacokinetic characteristics for extent and rate of absorption were AUC(0-24h) and % PTF, respectively. To assess the pharmacodynamic effect of metoprolol the excess area under the effect vs. time curve was calculated for heart rate during ergometry (AUCexHR). Point estimate and 90% confidence limits (CI) for the ratios of population medians of T and R were given. The respective point estimates (90% CI) of the ratios of both primary and secondary characteristics were entirely within the equivalence range of 0.80 and 1.25 for both enantiomers of metoprolol. Moreover, equivalence could be shown for the pharmacodynamic characteristic AUCexHR. Hence, it was concluded that pantoprazole does not interact with metoprolol pharmacokinetics or pharmacodynamics. Therefore, no dose adjustment of metoprolol during therapy with pantoprazole is necessary.


Assuntos
Antagonistas Adrenérgicos beta/farmacocinética , Antiulcerosos/farmacologia , Benzimidazóis/farmacologia , Metoprolol/farmacocinética , Inibidores da Bomba de Prótons , Sulfóxidos/farmacologia , 2-Piridinilmetilsulfinilbenzimidazóis , Administração Oral , Antagonistas Adrenérgicos beta/administração & dosagem , Antagonistas Adrenérgicos beta/farmacologia , Adulto , Antiulcerosos/administração & dosagem , Benzimidazóis/administração & dosagem , Análise Química do Sangue , Estudos Cross-Over , Método Duplo-Cego , Interações Medicamentosas , Teste de Esforço , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Masculino , Metoprolol/administração & dosagem , Metoprolol/sangue , Metoprolol/farmacologia , Omeprazol/análogos & derivados , Pantoprazol , Estereoisomerismo , Sulfóxidos/administração & dosagem
17.
Int J Clin Pharmacol Ther ; 36(10): 521-4, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9799054

RESUMO

OBJECTIVE: Pantoprazole is a H+/K+-ATPase inhibitor with a minimized potential of interaction with the cytochrome P450 system. Imidazole derivatives such as cimetidine and omeprazole have been shown to markedly interact with carbamazepine, a major anticonvulsant with a narrow therapeutic range. Therefore, the influence of steady-state pantoprazole on the pharmacokinetics of carbamazepine was investigated. SUBJECTS AND METHODS: N = 20 healthy volunteers (12 male/8 female) completed a double-blind, placebo-controlled, randomized crossover study. During the test period they received 40 mg pantoprazole p.o. once daily for 11 days and concomitantly a single oral dose of 400 mg carbamazepine on day 5. In the reference period placebo was administered instead of pantoprazole. RESULTS: Serum concentrations of carbamazepine and its active metabolite carbamazepine-10,11-epoxide were measured until day 11. Geometric means of AUC (extent characteristic) and Cmax/AUC (rate characteristic) of carbamazepine were 292 and 287 mgxh/l, and 0.0150 and 0.0144 l/h (reference and test), respectively. Point estimates and 90% confidence intervals of the ratios were 0.98 (0.95, 1.01) for AUC, and 0.96 (0.92, 1.00) for Cmax/AUC, respectively. Since the 90% confidence intervals of the primary characteristics, AUC and Cmax/AUC were entirely within the predefined equivalence range of 0.80 - 1.25, lack of interaction of pantoprazole with the pharmacokinetics of carbamazepine was demonstrated. Equivalence was also demonstrated for carbamazepine-10,11-epoxide using the characteristics AUC and Cmax. CONCLUSION: No dose adjustment of carbamazepine is therefore required during concomitant treatment with pantoprazole.


Assuntos
Anticonvulsivantes/farmacocinética , Benzimidazóis/farmacologia , Carbamazepina/farmacocinética , Inibidores Enzimáticos/farmacologia , Inibidores da Bomba de Prótons , Sulfóxidos/farmacologia , 2-Piridinilmetilsulfinilbenzimidazóis , Adulto , Anticonvulsivantes/efeitos adversos , Área Sob a Curva , Benzimidazóis/efeitos adversos , Biotransformação , Carbamazepina/efeitos adversos , Estudos Cross-Over , Método Duplo-Cego , Interações Medicamentosas , Inibidores Enzimáticos/efeitos adversos , Feminino , Humanos , Masculino , Omeprazol/análogos & derivados , Pantoprazol , Sulfóxidos/efeitos adversos
18.
Int J Clin Pharmacol Ther ; 37(4): 159-64, 1999 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10235417

RESUMO

OBJECTIVE: This drug-drug interaction study investigated the potential influence of the proton pump inhibitor pantoprazole on the CYP1A2 activity as assessed by urinary excretion of caffeine metabolites. SUBJECTS, MATERIALS AND METHODS: 12 healthy, non-smoking volunteers underwent two treatment periods of 7 days each in randomized order with once-daily oral intake of 40 mg pantoprazole (test) or placebo (reference). On days 6 and 7 of both periods, 200 mg caffeine was administered two hours after pantoprazole intake, i.e. at the expected t(max) of pantoprazole serum concentrations. Urinary excretion of the caffeine metabolites 1X, 1U, AFMU, 17U was measured up to 8 hours after caffeine intake. In accordance with recent guidelines on drug-drug interactions, lack of interaction was handled as an equivalence problem. RESULTS: Point estimate and 90% confidence intervals (CI) of the respective ratios test/reference were 0.91 (0.81, 1.03) for (1X + 1U + AFMU)/17U, indicative for CYP1A2 activity, 1.03 (0.94, 1.13) for AFMU/1X (N-acetyl transferase activity) and 1.01 (0.94, 1.09) for 1U/1X (xanthine oxidase activity). CONCLUSION: Pantoprazole does not induce CYP1A2 activity, consistent with previous findings following theophylline administration, nor does it have any influence on N-acetyl-transferase or xanthine oxidase activity.


Assuntos
Benzimidazóis/farmacologia , Cafeína/metabolismo , Estimulantes do Sistema Nervoso Central/metabolismo , Citocromo P-450 CYP1A2/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Inibidores da Bomba de Prótons , Sulfóxidos/farmacologia , 2-Piridinilmetilsulfinilbenzimidazóis , Administração Oral , Adulto , Área Sob a Curva , Benzimidazóis/sangue , Benzimidazóis/farmacocinética , Estudos Cross-Over , Citocromo P-450 CYP1A2/metabolismo , Método Duplo-Cego , Interações Medicamentosas , Inibidores Enzimáticos/sangue , Inibidores Enzimáticos/farmacocinética , Humanos , Masculino , Omeprazol/análogos & derivados , Pantoprazol , Sulfóxidos/sangue , Sulfóxidos/farmacocinética , Xantina Oxidase/metabolismo
19.
Int J Clin Pharmacol Ther ; 39(10): 453-9, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11680670

RESUMO

AIMS: To investigate pharmacokinetic characteristics of omeprazole MUPS 20 mg tablets and its encapsulated form. MATERIAL AND METHODS: Bioequivalence of omeprazole MUPS 20 mg tablet (Reference) and omeprazole MUPS 20 mg tablet in a hard gelatine capsule (Test) was evaluated in a randomized, 2-period crossover study in 38 healthy male Caucasian subjects who received a single oral dose of 20 mg omeprazole in each study period. Serum concentrations of omeprazole MUPS 20 mg were measured using an HPLC assay. In addition, in vitro dissolution profiles were studied. RESULTS: Both formulations were bioequivalent as assessed by the primary pharmacokinetic characteristics AUC(0-infinity) and Cmax, the corresponding ratios (Test/Reference) being 0.97 and 0.98, respectively. Thus, the 90% CI of these ratios were within the equivalence range of 0.8 to 1.25 for AUC(0-infinity) (CI 0.90-1.04) and 0.67 to 1.50 for Cmax (Cl 0.86-1.10). The ratios of the secondary criteria, Cmax/AUC(0-infinity) and t 1/2, were also within the equivalence range. Median tmax of Reference and Test was identical. Both formulations revealed comparable dissolution profiles with high batch conformity and homogeneity releasing > 80% omeprazole within 1 hour. Both study formulations were well tolerated without relevant differences. CONCLUSION: The encapsulation of omeprazole MUPS 20 mg tablets does not influence the extent and rate of absorption as indicated by the AUC and Cmax ratios. Thus, bioequivalence could be demonstrated.


Assuntos
Antiulcerosos/farmacocinética , Omeprazol/farmacocinética , Adulto , Antiulcerosos/sangue , Área Sob a Curva , Química Farmacêutica , Estudos Cross-Over , Meia-Vida , Humanos , Absorção Intestinal , Masculino , Omeprazol/sangue , Comprimidos com Revestimento Entérico , Equivalência Terapêutica
20.
Methods Find Exp Clin Pharmacol ; 21(1): 47-51, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10222447

RESUMO

The effects on intragastric p11 and gastrin secretion of once daily pantoprazole (40 mg) and a new formulation omeprazole (20 mg) in a Multiple Unit Pellet System (MUPS) were investigated during two treatment periods of 7 days each in a randomized crossover study with 16 healthy Helicobacter pylori-negative male volunteers. Intragastric pH was measured using continuous 24 hour pH-metry on days 1 and 7. The results were compared to the baseline curves obtained before each treatment period. On day 1, pantoprazole raised the intragastric pH significantly higher and more quickly than omeprazole MUPS (pH median 1.9 vs. 1.6, baseline pH 1.4). After 7 days, the 24 h gastric pH medians were still in favor of pantoprazole (pH 3.0 vs. 2.8). With respect to the basal gastrin concentration, both treatments resulted in similar increases. For pantoprazole, no differences were observed in AUC and Cmax after single and repeated dosing. However, the new omeprazole MUPS formulation still showed the well-known effect of initial low bioavailability increasing after repeated dosing. Pantoprazole and omeprazole were well tolerated. There seems to be no advantage in the new omeprazole formulation compared with the conventional capsule with regard to bioavailability and increase in intragastric pH. The results of this study confirm former results in which pantoprazole (40 mg) was shown to be significantly superior to omeprazole (20 mg) in elevating intragastric pH.


Assuntos
Antiulcerosos/farmacocinética , Benzimidazóis/farmacocinética , Omeprazol/farmacocinética , Sulfóxidos/farmacocinética , 2-Piridinilmetilsulfinilbenzimidazóis , Administração Oral , Adulto , Antiulcerosos/administração & dosagem , Benzimidazóis/administração & dosagem , Estudos Cross-Over , Método Duplo-Cego , Gastrinas/sangue , Humanos , Concentração de Íons de Hidrogênio , Masculino , Omeprazol/administração & dosagem , Pantoprazol , Sulfóxidos/administração & dosagem
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