Our work includes the assessment, modulation and modelling of the pharmacokinetics of prospective drugs and prodrugs. We are particularly interested in intestinal membrane transport and metabolism and in drug-drug interactions.
In vitro models for prediction of drug absorption and metabolism.
Among the in vitro systems used for the study of drug intestinal absorption the Caco-2 cell model is the most popular. Although the model provides significant information in terms of active transport and efflux prediction, it lacks modulation of pre-absorption metabolism. Differentiated Caco-2 cell monolayers express most drug-metabolizing enzymes and transporters but fail to express some relevant enzymes at the same relative level that they can be encountered in the intestine. Our laboratory is currently developing, in collaboration with the Animal Cell Technology group, an improved Caco-2 model that can express those enzymes.
The issue of drug-drug interactions has generated significant concern within the pharmaceutical industry and among US and European regulatory authorities in recent years, since co-administration of different drugs or dietary supplements can affect the therapeutic outcome of the drugs. These interactions may be due to metabolizing or transport enzyme inhibition/induction and affect pharmacokinetics or pharmacodynamic properties of the drug,
In our group, we are currently studying the effect that some dietary supplement formulations may have in the metabolism of prescription drugs.
Modulation of the absorption of bioactive compounds.
Since the discovery of fullerenes, various biological activities of their derivatives have been claimed, mostly related to fullerene free radical quenching ability. Surprisingly these compounds have not yet found their way to the clinic, which is probably related to their usual low water solubility that makes formulation and biological testing quite difficult.
Extremely low water solubility of this class of compounds has precluded activity tests in physiologically related media. We are studying ways to overcome this problem and investigating the antioxidant potential, toxicity and proliferative effects as well as the ability of fullerenes and fullerene conjugates to cross biological membranes.
In capillary reactions
In the field of analytical development we are particularly interested in in-capillary reactions. Electro-mediated micro analysis has been frequently used to follow enzymatic reactions; however, correlation with off-line methodologies is difficult because the fluid dynamics inside the capillary is not thoroughly characterized. We are now engaged in the evaluation of in-capillary reactions for the study of enzyme kinetics, taking into consideration stacking and/or diffusion effects.
Solubilization of fullerene C60 in micellar solutions of different solubilizers. Torres V M Posa, M Srdjenovic B & Simplício A L Colloids and Surfaces B: Biointerfaces. 2011 82(1):46-53.
Detection and Quantification of Carboxylesterase 2 Activity by Capillary Electrophoresis. Lamego J, Coroadinha AS, Simplício AL. Anal Chem. 2011 Feb 1;83(3):881-887. Epub 2011 Jan 5.
Electrophoretically mediated microanalysis for the evaluation of interspecies variation in cholinesterase metabolism. Moura J. & Simplício A L Electrophoresis 2010 31(14), 2374-2376.
Simultaneous determination of clopidogrel and its carboxylic acid metabolite by capillary electrophoresis. Serra H Bronze M d R & Simplício A L. J. Chrom. B: Analytical Technologies in the Biomedical and Life Sciences 2010 878(19), 1480-1486.
Sodium dodecyl sulfate-capillary gel electrophoresis analysis of rotavirus-like particles. Mellado MC, Franco C, Coelho A, Alves PM, Simplício AL. J Chromatogr A. 2008 May 23;1192(1):166-72.
Prediction of intestinal absorption and metabolism of pharmacologically active flavones and flavanones. Serra H, Mendes T, Bronze MR, Simplício AL. Bioorg Med Chem. 2008 Apr 1;16(7):4009-18. Epub 2008 Jan 19.
Ana Luisa Simplicio (Ph.D)
Pharmacokinetics and Biopharmaceutical Analysis
Phone (+351) 214 469 741