LC-MS/MS analysis of the plasma concentrations of a cocktail of 5 cytochrome P450 and P-glycoprotein probe substrates and their metabolites using subtherapeutic doses

Limited Sampling Modeling for Estimation of Phenotypic Metrics for CYP Enzymes and the ABCB1 Transporter Using a Cocktail Approach

“…In the present study, LSS strategies were applied to predict phenotypic metrics for a cocktail of probe drugs for CYP enzymes and the ABCB1 transporter. Plasma concentration data for the probe drugs and their metabolites in 2,640 samples collected from 16 closely monitored, healthy volunteers (Cusinato et al, 2019a) were used for development and subsequent validation of LSS models. All the probe drugs, namely caffeine (CYP1A2 probe), midazolam (CYP3A), omeprazole (CYP2C19), metoprolol (CYP2D6), and fexofenadine (ABCB1) have been previously included, albeit in higher doses, in phenotypic cocktails, notably the Basel (Donzelli et al, 2014) and the Geneva cocktails (Bosilkovska et al, 2014).…”

“…Details of the original trial, which was approved by the Ethics Committee of the Teaching Hospital of the Ribeirão Preto Medical School, University of São Paulo, and the effects of the propolis formulation have been published elsewhere (Cusinato et al, 2019a). Briefly, 16 healthy adults (11 men) ingested, on two occasions separated by 15 days, a capsule containing subtherapeutic doses of the phenotypic probes caffeine (10 mg; probe for CYP1A2), losartan (2 mg; CYP2C9), metoprolol (10 mg; CYP2D6), midazolam (0.2 mg; CYP3A), omeprazole (2 mg; CYP2C19), and fexofenadine (10 mg; ABCB1).…”

“…A total of 1,320 plasma concentration data points were available for LSS development. In addition to the plasma concentration data, CYP2C19 and CYP2D6 genotypes and inferred phenotypes were available for all subjects enrolled in the trial (Cusinato et al, 2019a). One subject classified as CYP2D6 poor metabolizer (genotype CYP2D6*4/*4) was excluded from the LSS modeling for metoprolol:a-OH metoprolol, since the plasma concentration of the metabolite was below the limit of quantification in most samples.…”

“…The present article examines the impact of increasing the number of sampling time-points on the accuracy of phenotypic metrics for cytochrome P450 (CYP) enzymes and the ABCB1 transporter. We applied limited sampling strategy (LSS) modeling to plasma concentration data from a trial in which a cocktail of subtherapeutic doses of selective probes was used to investigate the effects of a Brazilian propolis extract on the metabolic activity of CYP enzymes (CYP1A2, CYP2C9, CYP2C19, and CY2D6) and the drug transporter ABCB1 (Cusinato et al, 2019a). Propolis is a resinous balsamic material, with a complex chemical composition, that is collected by bees from sprouts, exudates of trees, and other parts of the plant sand mixed with wax and bee enzyme (Sforcin and Bankova, 2011).…”

“…Propolis is a resinous balsamic material, with a complex chemical composition, that is collected by bees from sprouts, exudates of trees, and other parts of the plant sand mixed with wax and bee enzyme (Sforcin and Bankova, 2011). The formulation used, which consists predominantly of green propolis from Baccharis dracuncufolia, was reported to have no clinically-relevant effect on the activity of the CYP enzymes examined or the ABCB1 drug transporter (Cusinato et al, 2019a). The results of the present study show that single-point LSS models for metoprolol and omeprazole provide highly accurate estimates of the metabolic activity of CYP2C19 and CYP2D6, but 2-point LSS models are required to obtain comparable accuracy when caffeine, midazolam, or fexofenadine are used as probes for CYP1A2, CYP3A, and the drug transporter, ABCB1, respectively.…”