Geneva Cocktail for Cytochrome P450 and P-Glycoprotein Activity Assessment Using Dried Blood Spots

Abstract

The suitability of the capillary dried blood spot (DBS) sampling method was assessed for simultaneous phenotyping of cytochrome P450 (CYP) enzymes and P-glycoprotein (P-gp) using a cocktail approach. Ten volunteers received an oral cocktail capsule containing low doses of the probes bupropion (CYP2B6), flurbiprofen (CYP2C9), omeprazole (CYP2C19), dextromethorphan (CYP2D6), midazolam (CYP3A), and fexofenadine (P-gp) with coffee/Coke (CYP1A2) on four occasions. They received the cocktail alone (session 1), and with the CYP inhibitors fluvoxamine and voriconazole (session 2) and quinidine (session 3). In session 4, subjects received the cocktail after a 7-day pretreatment with the inducer rifampicin. The concentrations of probes/metabolites were determined in DBS and plasma using a single liquid chromatography–tandem mass spectrometry method. The pharmacokinetic profiles of the drugs were comparable in DBS and plasma. Important modulation of CYP and P-gp activities was observed in the presence of inhibitors and the inducer. Minimally invasive one- and three-point (at 2, 3, and 6 h) DBS-sampling methods were found to reliably reflect CYP and P-gp activities at each session.

Rivaroxaban-Induced Hemorrhage Associated with ABCB1 Genetic Defect

“…According to the FDA classification 1 , simvastatin would therefore be considered as a weak CYP3A/5 inhibitor (≥1.25 but <2-fold increase in AUC). CYP3A4/5 phenotyping, which was performed 8 days after the patient had been switched from simvastatin to atorvastatin, showed moderately decreased enzymatic activity as compared to our study population of healthy volunteers (Bosilkovska et al, 2014), which could be attributed at least in part to inhibition by atorvastatin. Although the enzymatic activity was only modestly decreased with a OH-midazolam/midazolam metabolic ratio of 0.31, compared to 0.50 in healthy volunteers without enzyme inhibitor/inducer, and 0.22 in the presence of a CYP inhibitor (voriconazole) (Bosilkovska et al, 2014), the measured phenotype allowed to rule out an ultrarapid metabolism.…”

“…Midazolam was used as a probe to measure the joint activity of CYP3A4/5 as previously described (Bosilkovska et al, 2014). Phenotyping was performed 8 days after hospital admission with concomitant treatment of insulin, enoxaparin 60 mg b.i.d., atorvastatin 40 mg q.d.…”

Comparison of Liver Cell Models Using the Basel Phenotyping Cocktail

“…Several cocktails have been characterized in clinical studies and are used in individual patients, including the Karolinska cocktail (Christensen et al, 2003), the Cooperstown 5+1 cocktail (Chainuvati et al, 2003), the Geneva cocktail (Bosilkovska et al, 2014) and the Basel Cocktail (Donzelli et al, 2014). These cocktails have also been shown to be valuable tools to assess the capacity of drugs to induce or inhibit CYPs (Bosilkovska et al, 2014; Derungs et al, 2016). Drug cocktails have also been used to perform in vitro studies, in particular when assessing the CYP inhibition and induction potential of chemical compounds (Youdim et al, 2007; Mori et al, 2009; Spaggiari et al, 2014).…”

Alternative Sampling Strategies for Cytochrome P450 Phenotyping

“…In contrast to Donzelli et al, the higher volume, combined with the use of more sensitive equipment, allowed quantification of all probe drugs and corresponding metabolites in DBS. Single point metabolite/parent drug ratios at 2 h for CYP1A2 and CYP3A4 and at 3 h for CYP2B6, CYP2C9 and CYP2D6, and the AUC 2,3,6 metabolite/parent drug ratio for CYP2C19 showed acceptable Spearman rank correlation coefficients with AUC last ratios in plasma, both when the cocktail was administered alone or in combination with CYP450 inhibitor and inducer drugs [43,44].…”