Article Figures & Data
Figures
- Fig. 1.
Chemical structures of the analyzed COMT inhibitors.
- Fig. 2.
Intracellular accumulation of rhodamine-123 and Hoechst 33342 in MDCK II, MDCK-MDR1, and MDCK-BCRP cells. (A and B) Demonstration of P-gp and BCRP functionality after a 30-minute incubation period with 100 µM verapamil (A) or 0.5 µM Ko143 (B) as positive controls. (C and D) Intracellular uptake observed following a 30-minute incubation period with 100 µM test compounds in MDCK-MDR1 (C) and MDCK-BCRP (D) cells. Data compared with negative control cells (no inhibitor) and expressed as mean ± S.D. (n = 3). *P < 0.05; **P < 0.01; ***P < 0.001.
- Fig. 3.
Dose-dependent inhibition of BCRP-mediated accumulation of Hoechst 33342 by BIA 9-1079 (A), nebicapone (B), and tolcapone (C) in MDCK-BCRP cells. Values represent mean ± S.D. (n = 3).
- Fig. 4.
Mean concentration-time profiles of BIA 9-1079 and tolcapone in plasma (A) and brain (B) following 10 mg/kg intravenous administration to Wistar rats. Each data point is presented as mean ± S.E.M. (n = 27–30 animals per group). The mean concentration-time profiles of BIA 9-1079 and tolcapone in plasma (C and E) and brain (D and F) with and without the coadministration of elacridar (2.5 mg/kg) are depicted. Each data point is presented as mean ± S.E.M. (n = 8–12 animals per group) and significant differences between group concentrations at specific time points were calculated by two-tailed Student’s t test. *P < 0.05; **P < 0.01.
Tables
- TABLE 1
Bidirectional Papp coefficient, ER, and net flux ratio of reference compounds across MDCK II, MDCK-MDR1, and MDCK-BCRP cell monolayers
The Papp values are indicated from the AP-BL and BL-AP compartments and are expressed as mean (S.D.) (n = 3). ERs and net flux ratios greater than 2 are marked in bold. Transport classification according to Mahar Doan et al. (2002), Pavek et al. (2005), Wang et al. (2005), Feng et al. (2008), and Urquhart et al. (2008).
Reference Compound Transport Donor Solution MDCK II MDCK-MDR1 Net Flux Ratio MDCK-BCRP Net Flux Ratio Papp,AP-BL (×10−6) Papp,BL-AP (×10−6) ER Papp,AP-BL (×10−6) Papp,BL-AP (×10−6) ER Without Verapamil With Verapamil Papp,AP-BL (×10−6) Papp,BL-AP (×10−6) ER Without Ko143 With Ko143 μM cm/s cm/s cm/s cm/s cm/s cm/s Carbamazepine PT 10 36.5 (1.93) 19.5 (0.60) 0.53 38.0 (2.54) 20.0 (5.53) 0.53 1.00 — 37.3 (5.60) 19.6 (3.85) 0.53 1.00 — Propranolol PT 10 19.6 (4.99) 20.0 (0.16) 1.02 23.8 (2.69) 20.8 (1.51) 0.87 0.85 — 25.4 (2.51) 22.4 (0.59) 0.88 0.86 — Trazodone PT 10 38.5 (3.30) 29.4 (1.31) 0.76 33.0 (2.58) 40.4 (3.14) 1.22 1.61 — 37.5 (5.03) 27.4 (2.91) 0.73 0.96 — Atenolol PP 100 0.22 (0.06) 0.28 (0.03) 1.27 0.35 (0.14) 0.24 (0.04) 0.69 0.54 — 0.14 (0.11) 0.20 (0.03) 1.43 1.13 — Cimetidine Effluxa 30 0.56 (0.14) 0.43 (0.03) 0.75 0.06 (0.02) 0.41 (0.05) 6.40 8.50 0.89 0.15 (0.04) 1.25 (0.08) 8.34 11.1 1.47 Quinidine Effluxb 10 9.52 (2.53) 12.5 (2.49) 1.31 3.77 (0.91) 29.1 (1.37) 7.73 5.90 1.13 12.0 (3.48) 15.0 (0.48) 1.25 0.95 — Sulfasalazine Effluxc 60 0.81 (0.30) 0.28 (0.05) 0.34 0.30 (0.14) 0.17 (0.09) 0.56 1.64 — 0.13 (0.11) 0.30 (0.05) 2.31 6.79 0.92 Na-F PP 100 0.48 (0.09) — — 0.09 (0.08) — — — — 0.11 (0.04) — — — — - TABLE 2
The Papp coefficient values, ER, and net flux ratio of COMT inhibitors across MDCK II, MDCK-MDR1, and MDCK-BCRP cell monolayers
The Papp values are indicated from the AP-BL and BL-AP compartments and are expressed as mean (S.D.) (n = 3). ERs and net flux ratios greater than 2 are marked in bold.
Test Compound Donor Solution MDCK II MDCK-MDR1 Net Flux Ratio MDCK-BCRP Net Flux Ratio Papp,AP-BL (×10−6) Papp,BL-AP (×10−6) ER Papp,AP-BL (×10−6) Papp,BL-AP (×10−6) ER Without Verapamil With Verapamil Papp,AP-BL (×10−6) Papp,BL-AP (×10−6) ER Without Ko143 With Ko143 μM cm/s cm/s cm/s cm/s cm/s cm/s BIA 9-1059 60 1.29 (0.27) 1.47 (0.18) 1.14 1.22 (0.23) 0.35 (0.07) 0.29 0.25 — 0.24 (0.08) 1.69 (0.44) 7.04 6.18 0.64 BIA 9-1079 10 5.23 (2.75) 8.47 (0.91) 1.62 3.47 (1.77) 15.9 (4.19) 4.58 2.83 0.60 7.14 (4.63) 13.6 (1.74) 1.90 1.17 — Entacapone 30 6.33 (0.37) 6.02 (0.39) 0.95 3.51 (1.33) 1.29 (0.36) 0.37 0.39 — 0.98 (0.19) 11.1 (0.92) 11.3 11.9 1.06 Nebicapone 10 24.6 (1.45) 17.6 (4.18) 0.72 23.9 (7.06) 14.3 (2.60) 0.60 0.83 — 5.40 (0.09) 11.6 (0.63) 2.15 2.99 1.07 Opicapone 30 4.72 (2.33) 6.08 (0.38) 1.29 2.56 (1.08) 2.50 (0.39) 0.98 0.76 — 0.42 (0.09) 9.73 (1.13) 23.2 18.0 1.58 Tolcapone 10 26.6 (5.07) 20.6 (3.87) 0.77 24.3 (2.84) 19.5 (3.37) 0.80 1.04 — 28.3 (2.93) 23.7 (1.65) 0.84 1.09 — - TABLE 3
Pharmacokinetic parameters of BIA 9-1079 and tolcapone in plasma and brain after intravenous administration (10 mg/kg) to Wistar rats
The Cmax values are expressed in micrograms/gram and the AUC is expressed in micrograms.hour/gram in brain tissue.
Test Compound tmax Cmax AUC0-t AUC0-inf AUCextrap Kel t1/2el MRT h μg/ml μg.h/ml μg.h/ml % /h h h BIA 9-1079 Plasma 0.03 52.78 84.08 84.94 1.02 0.13 5.39 2.46 Brain 0.08 0.096 0.017 NC NC 0.66 1.05 0.23 Tolcapone Plasma 0.03 67.12 36.24 36.28 0.10 0.51 1.36 1.09 Brain 0.03 0.205 0.056 0.057 1.79 1.53 0.45 0.38 AUCextrap, extrapolated area under the concentration-time curve; AUC0-inf, area under the concentration-time curve from time zero to infinite; AUC0-t, area under the concentration-time curve from time zero to the last measurable concentration; Kel, apparent elimination rate constant; MRT, mean residence time; NC, not calculated; t1/2el, apparent terminal elimination half-life; tmax, time to achieve the maximum concentration.
- TABLE 4
Pharmacokinetic parameters and binding data of BIA 9-1079 and tolcapone in plasma and brain after intravenous administration (10 mg/kg) to Wistar rats
The presented Vu,bram,pred, Kp,uu,cyto,pred, Kp,uu,lyso,pred, and Kp,uu,ceii,pred values were predicted according to the pH partitioning theory. The fu,plasma and fu,brain values are expressed as mean (S.D.), n = 4.
Test Compound Kp fu,plasma fu,brain fu,brain,corrected Vu,brain,pred Kp,uu Kp,uu,cyto,pred Kp,uu,lyso,pred Kp,uu,cell,pred ml/g BIA 9-1079 0.0002 0.002 (0.001) 0.008 (0.001) 0.013 79.27 0.001 0.577 0.020 0.656 Tolcapone 0.0015 0.011 (0.003) 0.162 (0.028) 0.247 4.047 0.035 0.575 0.013 0.655 fu,plasma, unbound drug fraction in plasma; Kp, ratio of total brain-to-plasma AUC0-t; Kp,uu, unbound brain-to-plasma ratio; Kp,uu,cell,pred, predicted unbound drug intracellular-to-extracellular partitioning coefficient; Kp,uu,cyto,pred, predicted unbound cytosolic-to-extracellular drug concentration ratio; Kp,uu,lyso,pred, predicted lysosomic-to-cytosolic unbound drug concentration ratio; Vu,brain,pred, predicted volume of distribution of unbound drug in the brain.
- TABLE 5
Plasma and brain exposure of BIA 9-1079 and tolcapone after intravenous administration (10 mg/kg) to Wistar rats with or without coadministration of elacridar (2.5 mg/kg)
The AUC is expressed in micrograms.hour/gram in brain tissue.
Test Compound AUC0-t Kp Kp,uu Vehicle Elacridar Vehicle Elacridar Vehicle Elacridar μg.h/ml μg.h/ml BIA 9-1079 Plasma 32.71 37.34 0.001 0.003 0.007 0.017 Brain 0.037 0.095 Tolcapone Plasma 27.31 28.59 0.002 0.004 0.041 0.095 Brain 0.050 0.119 AUC0-t, area under the concentration-time curve from time zero to the last measurable concentration; Kp, ratio of total brain-to-plasma AUC0-t; Kp,uu, unbound brain-to-plasma ratio.
Data Supplement
- Supplemental Tables -
Supplemental Table 1 - Chromatographic conditions and validation parameters of HPLC-DAD techniques applied for the quantification of reference and test compounds in samples from in vitro and in vivo assays
Supplemental Table 2 - Stability (values in percentage) of COMT inhibitors in HBSS with 10mM HEPES pH 7.4 under cellular assay conditions (37º C for 120 min)
- Supplemental Tables -
In this issue
P-gp and BCRP Impact on the Brain Access of COMT Inhibitors
