Clinical treatment for hepatitis C reverses CYP2C19 inhibition.

AIMS: Infection by the hepatitis C virus (HCV) generates inflammatory response selectively modulating cytochrome P450 protein (CYP) activities. This study assessed the effect of chronic hepatitis C on CYP2C19 activity in patients with HCV. METHODS: Patients with HCV infection (n = 23) at different fibrosis stages were allocated into groups 1 (F0/F1 and F2, mild to moderate fibrosis) and 2 (F3 and F4, advanced fibrosis stages). Phase 1 was conducted before the treatment with direct-acting antivirals (DAAs) and phase 2 after the sustained virological response. Participants were administered 2 mg of a single oral dose of omeprazole (OME) as probe drug in both phases. Metabolic ratios (MRs) (plasma samples collected at 4 h after OME administration) were calculated by dividing plasma concentrations of 5-hydroxyomeprazole by OME. RESULTS: The MRs for group 1 were 0.45 (0.34-0.60, 90% confidence interval) and 0.69 (0.50-0.96) for phases 1 and 2, respectively, while the MRs for group 2 were 0.25 (0.21-0.31) and 0.41 (0.30-0.56) for phases 1 and 2, respectively. MRs were different (P < .05) between phases 1 and 2 for both groups, as well as between groups 1 and 2 in phase 1, but not in phase 2 (P > .05). CONCLUSIONS: Both groups presented different MRs before and after treatment with DAAs, evidencing that CYP2C19 inhibition during inflammation was at least partially reversed after DAA treatment. Groups 1 and 2 were also found to be different in phase 1 but not phase 2, showing that CYP2C19 metabolic activity does not differ between groups after DAA treatment.

Effect of Chronic Hepatitis C on the Activity of the Membrane Transporters P-gp and OATP1B1/BCRP on Patients With Different Stages of Hepatic Fibrosis.

The activity of the membrane transporters organic anion-transporting polypeptide 1B1 (OATP1B1) & breast cancer resistance protein (BCRP) (rosuvastatin) and P-glycoprotein (P-gp) (fexofenadine) was evaluated in patients with chronic hepatitis C virus (HCV) infection (n = 28), genotypes 1 and 3, investigated before the treatment with direct-acting antiviral agents (Phase 1) and up to 30 days after the assessment of the virologic response (Phase 2). Participants allocated in Groups 1 (n = 15; F0/F1 and F2, mild to moderate liver fibrosis) and 2 (n = 13; F3 and F4, advanced course of liver fibrosis/cirrhosis) received in both phases fexofenadine (10 mg) and rosuvastatin (2 mg). OATP1B1 & BCRP activity (rosuvastatin area under the plasma concentration-time curve of rosuvastatin from time zero to infinity (AUC0-∞ )) was reduced in Groups 1 and 2, respectively, by 25% (ratio 0.75 (0.53-0.82), P < 0.01) and 31% (ratio 0.69 (0.46-0.85), P < 0.05) in Phase 1 compared with Phase 2. OATP1B1 & BCRP activity was reduced in Phases 1 and 2, respectively, by 49% (median ratio 1.51 (1.17-2.20), P < 0.05) and 61% (ratio 1.39 (1.16-2.02), P < 0.01) in Group 2 compared with Group 1. P-gp activity (fexofenadine AUC0-∞ ) was also reduced in Phase 1 compared with Phase 2 (ratio Phase2/Phase1 0.79 (0.66-0.96) in Group 1 and 0.81 (0.69-0.96) in Group 2) as well as in Group 2 compared with Group 1 in both Phases (ratio Group2/Group1 1.47 (1.08-2.01) in Phase 1 and 1.51 (1.10-2.07) in Phase 2). Thus, clinicians administering OATP1B1 & BCRP and P-gp substrates with low therapeutic indexes should consider the evolution of the treatment and the stage of HCV infection.

Automated analysis of lidocaine and its metabolite in plasma by in-tube solid-phase microextraction coupled with LC-UV for pharmacokinetic study.

A sensitive, selective, and reproducible in-tube solid-phase microextraction and liquid chromatographic (in-tube SPME/LC-UV) method for determination of lidocaine and its metabolite monoethylglycinexylidide (MEGX) in human plasma has been developed, validated, and further applied to pharmacokinetic study in pregnant women with gestational diabetes mellitus (GDM) subjected to epidural anesthesia. Important factors in the optimization of in-tube SPME performance are discussed, including the draw/eject sample volume, draw/eject cycle number, draw/eject flow rate, sample pH, and influence of plasma proteins. The limits of quantification of the in-tube SPME/LC method were 50 ng/mL for both metabolite and lidocaine. The interday and intraday precision had coefficients of variation lower than 8%, and accuracy ranged from 95 to 117%. The response of the in-tube SPME/LC method for analytes was linear over a dynamic range from 50 to 5000 ng/mL, with correlation coefficients higher than 0.9976. The developed in-tube SPME/LC method was successfully used to analyze lidocaine and its metabolite in plasma samples from pregnant women with GDM subjected to epidural anesthesia for pharmacokinetic study.

Plasma mevalonic acid exposure as a pharmacodynamic biomarker of fluvastatin/atorvastatin in healthy volunteers.

Fluvastatin and atorvastatin are inhibitors of hydroxy-methylglutaryl-CoA (HMG-CoA) reductase, the enzyme that converts HMG-CoA to mevalonic acid (MVA). The present study reports for the first time the analysis of mevalonolactone (MVL) in plasma samples by UPLC-MS/MS as well as the use of MVA, analyzed as MVL, as a pharmacodynamics parameter of fluvastatin in multiple oral doses (20, 40 or 80 mg/day for 7 days) and atorvastatin in a single oral dose (20, 40 or 80 mg) in healthy female volunteers. this study presents the use of MVL exposure as a pharmacodynamics biomarker of fluvastatin in multiple oral doses (20, 40 or 80 mg/day for 7 days) or atorvastatin in a single oral dose (20, 40 or 80 mg) in healthy volunteers (n = 30). The administration of multiple doses of fluvastatin (n = 15) does not alter the values (geometric mean and 95 % CI) of AUC0-24 h of MVL [72.00 (57.49-90.18) vs 65.57 (51.73-83.12) ng∙h/mL], but reduces AUC0-6 h [15.33 (11.85-19.83) vs 8.15 (6.18-10.75) ng∙h/mL] by approximately 47 %, whereas single oral dose administration of atorvastatin (n = 15) reduces both AUC0-24 h [75.79 (65.10-88.24) vs 32.88 (27.05-39.96) ng∙h/mL] and AUC0-6 h [17.07 (13.87-21.01) vs 7.01 (5.99-8.22) ng∙h/mL] values by approximately 57 % and 59 %, respectively. In conclusion, the data show that the plasma exposure of MVL represents a reliable pharmacodynamic parameter for PK-PD (pharmacokinetic-pharmacodynamic) studies of fluvastatin in multiple doses and atorvastatin in a single dose.

Rheumatoid arthritis downregulates the drug transporter OATP1B1: Fluvastatin as a probe.

AIMS: Rheumatoid arthritis (RA) is a long term autoimmune inflammatory disease characterized by high autoantibody production and cytokine release, especially IL-6 and TNF-α. Some clinical studies have shown the effect of RA on CYP metabolism. However, the effect of RA on the drug transporter OATP1B1 remains a gap. METHODS: Patients with RA under pharmacological treatment (n = 10) and healthy volunteers (n = 15) treated for seven consecutive days with racemic fluvastatin (20, 40, or 80 mg/24 h) were investigated. Serial blood samples were collected during the last dose interval. All participants were assessed for cytokine profile and CYP2C9 genotype. RESULTS: Patients with RA showed increased plasma concentrations of IFN-γ and TNF-α up to two and four times, respectively, when compared to healthy volunteers, whereas CYP2C9 activity based on genotype was considered normal or slightly reduced for both investigated groups. When compared to healthy volunteers, patients with RA presented higher values (median and 25th-75th percentiles) of normalized AUC for 20 mg dose (250 [114-405] vs. 96.7 [78.1-131] ng h mL-1 for (-)-3S,5R-fluvastatin and 163 [96.9-325] vs. 83.1 [61.7-107] ng⋅h⋅mL-1 for (+)-3R,5S-fluvastatin) and lower values of CL/F (40.9 [24.5-89.1] vs. 103 [75.9-128] L⋅h-1 for (-)-3S,5R-fluvastatin and 61.4 [30.6-103] vs. 120 [93.0-162] L⋅h-1 for (+)-3R,5S-fluvastatin) and V/F (73.0 [28.5-117] vs. 143 [108-221] L for (-)-3S,5R-fluvastatin and 93.9 [32.7-116] vs. 153 [122-234] L for (+)-3R,5S-fluvastatin) for both enantiomers. CONCLUSION: The lower values of CL/F and V/F for both fluvastatin enantiomers in RA patients suggest that the inflammatory disease downregulates the sinusoidal drug transporter OATP1B1, the rate-determining step in the hepatic clearance of fluvastatin.