A utilidade de ensaios in vitro com culturas celulares - Caco-2 - como substitutos da determinação da permeabilidade intestinal no animal e da bioequivalência no humano no desenvolvimento de novos fármacos
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Data
2015
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Edições Universitárias Lusófonas
Resumo
As células Caco-2 são amplamente utilizadas no rastreio da permeabilidade intestinal de novas moléculas, embora
com algumas limitações. A utilização de Caco-2 apenas para compostos com permeabilidade passiva elevada
é difícil, uma vez que a maioria dos medicamentos aprovados incluem difusão passiva e transporte ativo. Este
trabalho avalia a utilidade das células Caco-2 para previsão dos efeitos de efluxo mediados pela P-gp. O protocolo
experimental incluiu fármacos altamente solúveis e permeáveis (classe 1), verapamilo e diltiazem, um fármaco
altamente solúvel e pouco permeável (classe 3), digoxina e um inibidor da P-gp, GG918. Calcularam-se as
permeabilidades aparentes e as razões de efluxo (ER). A digoxina, controlo positivo para a P-gp, apresentou uma
ER de 4, que diminuiu para aproximadamente 1 por adição de GG918, consistente com um efeito da P-gp nestas
células. As ER para o verapamilo/ diltiazem situaram-se próximo da unidade na ausência e presença de GG918.
Estes resultados sugerem que a P-gp poderá desempenhar um papel irrelevante no transporte de fármacos de classe
1 em células Caco-2, enquanto o transporte de fármacos de classe 3 poderá ser significativamente afectado pela
P-gp. É proposto que as células Caco-2 podem ser úteis para determinar o papel da P-gp na absorção intestinal.
Caco-2 cells have been widely used for in vitro intestinal permeability screening of new molecules in drug development but with some pitfalls. Limiting the application of Caco-2 permeability screening to passive compounds is difficult as the majority of approved drugs include both passive diffusion and active transport. The aim of this study was to evaluate Caco-2 cells utility in assessing effects of P-gp mediated efflux. For that purpose the study design included the highly soluble, highly permeable (class 1), verapamil and diltiazem, the highly soluble and poorly permeable drug (class 3) digoxin and the P-gp inhibitor GG918. The apparent permeability and efflux ratio (ER) were calculated. Digoxin, a positive control for P-gp, presented an ER of 4, which decreased to around 1 by GG918 addition, consistent with a P-gp effect in Caco-2 cells. ER for verapamil and diltiazem was nearly 1 and the presence of GG918 resulted in no ERs changes. These results suggest that P-gp apparently plays a minimal role in transport of class 1 drugs across Caco-2 cells while class 3 drugs should be significantly affected by P-gp. It is suggested that Caco-2 cells may be useful to determine whether P-gp plays a relevant role in intestinal absorption.
Caco-2 cells have been widely used for in vitro intestinal permeability screening of new molecules in drug development but with some pitfalls. Limiting the application of Caco-2 permeability screening to passive compounds is difficult as the majority of approved drugs include both passive diffusion and active transport. The aim of this study was to evaluate Caco-2 cells utility in assessing effects of P-gp mediated efflux. For that purpose the study design included the highly soluble, highly permeable (class 1), verapamil and diltiazem, the highly soluble and poorly permeable drug (class 3) digoxin and the P-gp inhibitor GG918. The apparent permeability and efflux ratio (ER) were calculated. Digoxin, a positive control for P-gp, presented an ER of 4, which decreased to around 1 by GG918 addition, consistent with a P-gp effect in Caco-2 cells. ER for verapamil and diltiazem was nearly 1 and the presence of GG918 resulted in no ERs changes. These results suggest that P-gp apparently plays a minimal role in transport of class 1 drugs across Caco-2 cells while class 3 drugs should be significantly affected by P-gp. It is suggested that Caco-2 cells may be useful to determine whether P-gp plays a relevant role in intestinal absorption.
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FARMACOLOGIA, PHARMACOLOGY, MEDICAMENTOS, DRUGS, ABSORÇÃO INTESTINAL, NUTRIENT ABSORPTION, INTERAÇÃO COM MEDICAMENTOS, DRUG INTERACTIONS, EXPERIÊNCIAS LABORATORIAIS, LABORATORY EXPERIMENTS, CIÊNCIAS FARMACÊUTICAS, PHARMACEUTICAL SCIENCES