RESUMO
An amperometric drug metabolism biosensor consisting of cytochrome P450-3A4 (CYP3A4) encapsulated in a didodecyldimethylammonium bromide (DDAB) vesicular system on a Pt disk electrode was developed for the determination of indinavir, a protease inhibitor antiretroviral drug. Cyclic, square wave and pulse voltammetric responses of the bioelectrode showed quasi-reversible electrochemistry of the Fe(3+)/Fe(2+) redox species of the heme thiolate CYP3A4 enzyme under aerobic and anaerobic conditions. The biosensor exhibited excellent response to indinavir with a detection limit and response time of 6.158 x 10(-2)mgL(-1), and 40s, respectively. The detection limit is well below the plasma concentration of indinavir (8h after intake) which range from 0.13 to 8.6mgL(-1).
Assuntos
Técnicas Biossensoriais/métodos , Inibidores da Protease de HIV/metabolismo , Inibidores da Protease de HIV/uso terapêutico , Indinavir/metabolismo , Indinavir/uso terapêutico , Aerobiose , Anaerobiose , Técnicas Biossensoriais/instrumentação , Ensaios Clínicos Fase I como Assunto , Citocromo P-450 CYP3A/química , Eletricidade , Eletroquímica , Eletrodos , Enzimas Imobilizadas , Infecções por HIV/tratamento farmacológico , Inibidores da Protease de HIV/química , Indinavir/química , Estrutura Molecular , Oxirredução , Platina/química , Compostos de Amônio Quaternário/química , Prata/química , Compostos de Prata/química , Água/químicaRESUMO
The resource investment required to characterise the metabolic fate of a compound is relatively large, meaning that within a drug discovery environment relatively few compounds are characterised in depth. Rate-limiting steps include the setting up of a complex array of mass spectrometry experiments and the subsequent analysis of the large data sets produced. We describe here a strategy for the evaluation of metabolic routes using full-scan high-resolution liquid chromatography/quadrupole time-of-flight mass spectrometry (LC/QToFMS) with automated data analysis using Metabolynx, a commercially available software package. Data from several structurally diverse compounds taken from the literature illustrate that, with careful setting of key parameters, this approach is able to indicate the presence of a wide range of metabolites with only a limited requirement for manual intervention.
Assuntos
Avaliação Pré-Clínica de Medicamentos/métodos , Preparações Farmacêuticas/química , Preparações Farmacêuticas/metabolismo , Animais , Automação , Cromatografia Líquida , Diazepam/química , Diazepam/metabolismo , Indinavir/química , Indinavir/metabolismo , Espectrometria de Massas , Microssomos Hepáticos/metabolismo , Estrutura Molecular , Ratos , Padrões de Referência , Sensibilidade e Especificidade , Fatores de TempoRESUMO
AIDS: St. John's wort, an herbal treatment for depression, should not be combined with certain drugs, including some antiretrovirals. St. John's wort can speed up the body's elimination of some drugs. When HIV medications are used, blood levels could drop low enough to allow resistance to occur. So far, St. John's wort has been tested only with the protease inhibitor indinavir (Crixivan), but it is likely to affect other drugs in that class and possibly non-nucleoside reverse transcriptase inhibitors. This warning follows a study by the National Institutes of Health (NIH) on dosing and blood levels of indinavir in HIV-negative test subjects. More information on the study is available on The Lancet's Web site. The text of the FDA's advisory letter is included.^ieng