Bachmeier CJ, Miller DW. A Fluorometric Screening Assay for Drug Efflux Transporter Activity in the Blood-Brain Barrier.
Pharm Res 2005;
22:113-21. [PMID:
15771237 DOI:
10.1007/s11095-004-9016-0]
[Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE
To examine the capability of a fluorometric assay to identify and characterize the drug efflux interactions of a broad spectrum of drug agents in an in vitro model of the blood-brain barrier (BBB).
METHODS
Various concentrations of drug agent (1, 10, and 100 microM) were evaluated for their effect on the cellular accumulation of the P-glycoprotein (P-gp) probe R123 (3.2 microM), and the mixed P-gp and multidrug resistance-associated protein (MRP) probe, BCECF (1 microM), in bovine brain microvessel endothelial cell (BBMEC) monolayers. Drugs demonstrating a significant effect were further quantitated using an expanded concentration range and a nonlinear regression curve fit to determine the potency (IC50) and efficacy (Imax) of the drug for P-gp and/or MRP.
RESULTS
Several of the 36 therapeutic agents examined showed drug efflux transporter interactions in BBMEC monlayers. Melphalan and risperidone significantly enhanced the accumulation of R123 over control (1.47- and 1.82-fold, respectively) with resulting IC50s of 1.4 and 14.6 microM, respectively. Chlorambucil and valproic acid significantly enhanced the accumulation of BCECF compared to control monolayers (2.02- and 4.01-fold, respectively) with resulting IC50s of 146.1 and 768.5 microM, respectively.
CONCLUSIONS
The current study demonstrates the feasibility of a fluorometric assay consisting of R123 and BCECF in assessing the drug efflux interactions of a variety of drugs in the BBB.
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