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The putative P-gp inhibitor telmisartan does not affect the transcellular permeability and cellular uptake of the calcium channel antagonist verapamil in the P-glycoprotein expressing cell line MDCK II MDR1.

Saaby L, Tfelt-Hansen P, Brodin B - Pharmacol Res Perspect (2015)

Bottom Line: Zosuquidar (0.4 μmol/L) reduced the efflux ratio (PB-A/PA-B) for verapamil 4.6-1.6.The presence of telmisartan, however, only caused a slight reduction in P-gp-mediated verapamil transport to an efflux ratio of 3.4.Overall, the results of the present in vitro approach indicate, that clinical use of telmisartan as a P-gp inhibitor may not be an effective strategy for increasing brain uptake of verapamil by co-administration with telmisartan.

View Article: PubMed Central - PubMed

Affiliation: Bioneer:FARMA, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup Hospital Glostrup, Denmark ; Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen Copenhagen, Denmark.

ABSTRACT
Verapamil is used in high doses for the treatment of cluster headache. Verapamil has been described as a P-glycoprotein (P-gp, ABCB1) substrate. We wished to evaluate in vitro whether co administration of a P-gp inhibitor with verapamil could be a feasible strategy for increasing CNS uptake of verapamil. Fluxes of radiolabelled verapamil across MDCK II MDR1 monolayers were measured in the absence and presence of the putative P-gp inhibitor telmisartan (a clinically approved drug compound). Verapamil displayed a vectorial basolateral-to-apical transepithelial efflux across the MDCK II MDR1 monolayers with a permeability of 5.7 × 10(-5) cm sec(-1) compared to an apical to basolateral permeability of 1.3 × 10(-5) cm sec(-1). The efflux could be inhibited with the P-gp inhibitor zosuquidar. Zosuquidar (0.4 μmol/L) reduced the efflux ratio (PB-A/PA-B) for verapamil 4.6-1.6. The presence of telmisartan, however, only caused a slight reduction in P-gp-mediated verapamil transport to an efflux ratio of 3.4. Overall, the results of the present in vitro approach indicate, that clinical use of telmisartan as a P-gp inhibitor may not be an effective strategy for increasing brain uptake of verapamil by co-administration with telmisartan.

No MeSH data available.


Related in: MedlinePlus

(A) The apparent transepithelial permeability of [3H]-verapamil (12 μmol/L) in the apical to basolateral (grey bars) and basolateral to apical (white bars) direction across MDCK II (MDR1) cells in the presence or absence of zosuquidar (ZSQ, 0.4 μmol/L). Data represent the means ± SD (n = 9, N = 3). (B) Efflux ratios for [3H]-verapamil (12 μmol/L) across MDCK II (MDR1) cells in the presence or absence of zosuquidar (ZSQ, 0.4 μmol/L). Data points represent the calculated efflux ratio for individual cell culture passages (n = 9). Efflux ratio was calculated as the ratio between the basolateral to apical and the apical to basolateral apparent permeability from means of three filters (N = 3) for each treatment and direction. Connected data points originate from the same cell culture passage.
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fig02: (A) The apparent transepithelial permeability of [3H]-verapamil (12 μmol/L) in the apical to basolateral (grey bars) and basolateral to apical (white bars) direction across MDCK II (MDR1) cells in the presence or absence of zosuquidar (ZSQ, 0.4 μmol/L). Data represent the means ± SD (n = 9, N = 3). (B) Efflux ratios for [3H]-verapamil (12 μmol/L) across MDCK II (MDR1) cells in the presence or absence of zosuquidar (ZSQ, 0.4 μmol/L). Data points represent the calculated efflux ratio for individual cell culture passages (n = 9). Efflux ratio was calculated as the ratio between the basolateral to apical and the apical to basolateral apparent permeability from means of three filters (N = 3) for each treatment and direction. Connected data points originate from the same cell culture passage.

Mentions: The bidirectional transport of verapamil across MDCK II (MDR1) cells was measured in the presence and in the absence of the known P-gp inhibitor zosuquidar (Slate et al. 1995; Dantzig et al. 1996) in order to investigate whether the observed B-A efflux of [3H]-verapamil was mediated by P-gp, (Fig.2A). In the presence of 0.4 μmol/L zosuquidar the B-A permeability of [3H]-verapamil was 3.8 ± 0.4 × 10−5 cm sec−1 (n = 9, N = 3) which was significantly lower (P < 0.0001) than the observed B-A permeability of 5.7 ± 0.8 × 10−5 cm sec−1 (n = 9, N = 3) in the absence of zosuquidar. Correspondingly, the A-B transport of [3H]-verapamil increased significantly (P < 0.0001) from 1.3 ± 0.2 × 10−5 cm sec−1 (n = 9, N = 3) in the absence of zosuquidar, to 2.3 ± 0.2 × 10−5 cm sec−1 (n = 9, N = 3) in the presence of 0.4 μmol/L zosuquidar (Fig.2A). Correspondingly, the efflux ratio of verapamil was significantly reduced (P < 0.0001) from 4.3 ± 0.4 (n = 3, N = 3) in the absence of zosuquidar to 1.6 ± 0.2 (n = 3, N = 3) in the presence of 0.4 μmol/L zosuquidar (Fig.2B). Overall, the presence of 0.4 μmol/L zosuquidar reduced the efflux ratio PB-A/PA-B of verapamil to a magnitude similar to that of the paracellular flux-marker mannitol, indicating that verapamil was a substrate for, and that the observed vectorial efflux of verapamil was caused solely by P-gp in the MDCK II (MDR1) cell monolayers.


The putative P-gp inhibitor telmisartan does not affect the transcellular permeability and cellular uptake of the calcium channel antagonist verapamil in the P-glycoprotein expressing cell line MDCK II MDR1.

Saaby L, Tfelt-Hansen P, Brodin B - Pharmacol Res Perspect (2015)

(A) The apparent transepithelial permeability of [3H]-verapamil (12 μmol/L) in the apical to basolateral (grey bars) and basolateral to apical (white bars) direction across MDCK II (MDR1) cells in the presence or absence of zosuquidar (ZSQ, 0.4 μmol/L). Data represent the means ± SD (n = 9, N = 3). (B) Efflux ratios for [3H]-verapamil (12 μmol/L) across MDCK II (MDR1) cells in the presence or absence of zosuquidar (ZSQ, 0.4 μmol/L). Data points represent the calculated efflux ratio for individual cell culture passages (n = 9). Efflux ratio was calculated as the ratio between the basolateral to apical and the apical to basolateral apparent permeability from means of three filters (N = 3) for each treatment and direction. Connected data points originate from the same cell culture passage.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492727&req=5

fig02: (A) The apparent transepithelial permeability of [3H]-verapamil (12 μmol/L) in the apical to basolateral (grey bars) and basolateral to apical (white bars) direction across MDCK II (MDR1) cells in the presence or absence of zosuquidar (ZSQ, 0.4 μmol/L). Data represent the means ± SD (n = 9, N = 3). (B) Efflux ratios for [3H]-verapamil (12 μmol/L) across MDCK II (MDR1) cells in the presence or absence of zosuquidar (ZSQ, 0.4 μmol/L). Data points represent the calculated efflux ratio for individual cell culture passages (n = 9). Efflux ratio was calculated as the ratio between the basolateral to apical and the apical to basolateral apparent permeability from means of three filters (N = 3) for each treatment and direction. Connected data points originate from the same cell culture passage.
Mentions: The bidirectional transport of verapamil across MDCK II (MDR1) cells was measured in the presence and in the absence of the known P-gp inhibitor zosuquidar (Slate et al. 1995; Dantzig et al. 1996) in order to investigate whether the observed B-A efflux of [3H]-verapamil was mediated by P-gp, (Fig.2A). In the presence of 0.4 μmol/L zosuquidar the B-A permeability of [3H]-verapamil was 3.8 ± 0.4 × 10−5 cm sec−1 (n = 9, N = 3) which was significantly lower (P < 0.0001) than the observed B-A permeability of 5.7 ± 0.8 × 10−5 cm sec−1 (n = 9, N = 3) in the absence of zosuquidar. Correspondingly, the A-B transport of [3H]-verapamil increased significantly (P < 0.0001) from 1.3 ± 0.2 × 10−5 cm sec−1 (n = 9, N = 3) in the absence of zosuquidar, to 2.3 ± 0.2 × 10−5 cm sec−1 (n = 9, N = 3) in the presence of 0.4 μmol/L zosuquidar (Fig.2A). Correspondingly, the efflux ratio of verapamil was significantly reduced (P < 0.0001) from 4.3 ± 0.4 (n = 3, N = 3) in the absence of zosuquidar to 1.6 ± 0.2 (n = 3, N = 3) in the presence of 0.4 μmol/L zosuquidar (Fig.2B). Overall, the presence of 0.4 μmol/L zosuquidar reduced the efflux ratio PB-A/PA-B of verapamil to a magnitude similar to that of the paracellular flux-marker mannitol, indicating that verapamil was a substrate for, and that the observed vectorial efflux of verapamil was caused solely by P-gp in the MDCK II (MDR1) cell monolayers.

Bottom Line: Zosuquidar (0.4 μmol/L) reduced the efflux ratio (PB-A/PA-B) for verapamil 4.6-1.6.The presence of telmisartan, however, only caused a slight reduction in P-gp-mediated verapamil transport to an efflux ratio of 3.4.Overall, the results of the present in vitro approach indicate, that clinical use of telmisartan as a P-gp inhibitor may not be an effective strategy for increasing brain uptake of verapamil by co-administration with telmisartan.

View Article: PubMed Central - PubMed

Affiliation: Bioneer:FARMA, Faculty of Health and Medical Sciences, University of Copenhagen, Glostrup Hospital Glostrup, Denmark ; Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen Copenhagen, Denmark.

ABSTRACT
Verapamil is used in high doses for the treatment of cluster headache. Verapamil has been described as a P-glycoprotein (P-gp, ABCB1) substrate. We wished to evaluate in vitro whether co administration of a P-gp inhibitor with verapamil could be a feasible strategy for increasing CNS uptake of verapamil. Fluxes of radiolabelled verapamil across MDCK II MDR1 monolayers were measured in the absence and presence of the putative P-gp inhibitor telmisartan (a clinically approved drug compound). Verapamil displayed a vectorial basolateral-to-apical transepithelial efflux across the MDCK II MDR1 monolayers with a permeability of 5.7 × 10(-5) cm sec(-1) compared to an apical to basolateral permeability of 1.3 × 10(-5) cm sec(-1). The efflux could be inhibited with the P-gp inhibitor zosuquidar. Zosuquidar (0.4 μmol/L) reduced the efflux ratio (PB-A/PA-B) for verapamil 4.6-1.6. The presence of telmisartan, however, only caused a slight reduction in P-gp-mediated verapamil transport to an efflux ratio of 3.4. Overall, the results of the present in vitro approach indicate, that clinical use of telmisartan as a P-gp inhibitor may not be an effective strategy for increasing brain uptake of verapamil by co-administration with telmisartan.

No MeSH data available.


Related in: MedlinePlus