Abstract
Thirty-one structurally diverse marketed central nervous system (CNS)-active drugs, one active metabolite, and seven non-CNS-active compounds were tested in three P-glycoprotein (P-gp) in vitro assays: transwell assays using MDCK, human MDR1-MDCK, and mouse Mdr1a-MDCK cells, ATPase, and calcein AM inhibition. Additionally, the permeability for these compounds was measured in two in vitro models: parallel artificial membrane permeation assay and apical-to-basolateral apparent permeability in MDCK. The exposure of the same set of compounds in brain and plasma was measured in P-gp knockout (KO) and wild-type (WT) mice after subcutaneous administration. One drug and its metabolite, risperidone and 9-hydroxyrisperidone, of the 32 CNS compounds, and 6 of the 7 non-CNS drugs were determined to have positive efflux using ratio of ratios in MDR1-MDCK versus MDCK transwell assays. Data from transwell studies correlated well with the brain-to-plasma area under the curve ratios between P-gp KO and WT mice for the 32 CNS compounds. In addition, 3300 Pfizer compounds were tested in MDR1-MDCK and Mdr1a-MDCK transwell assays, with a good correlation (R2 = 0.92) between the efflux ratios in human MDR1-MDCK and mouse Mdr1a-MDCK cells. Permeability data showed that the majority of the 32 CNS compounds have moderate to high passive permeability. This work has demonstrated that in vitro transporter assays help in understanding the role of P-gp-mediated efflux activity in determining the disposition of CNS drugs in vivo, and the transwell assay is a valuable in vitro assay to evaluate human P-gp interaction with compounds for assessing brain penetration of new chemical entities to treat CNS disorders.
Footnotes
-
Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
-
doi:10.1124/dmd.107.017434.
-
ABBREVIATIONS: P-gp, P-glycoprotein; MDR1/Mdr1a, multidrug resistance protein; BBB, blood-brain barrier; CNS, central nervous system; MDCK, Madin-Darby canine kidney; MDR1-MDCK, MDR1-transfected MDCK; Mdr1a-MDCK, Mdr1a-transfected MDCK; B/P, brain/plasma ratio; KO, knockout; WT, wild type; PAMPA, parallel artificial membrane permeation assay; DMSO, dimethylsulfoxide; A, apical; B, basolateral; MES, 4-morpholineethanesulfonic acid; MRM, multiple reaction monitoring; PBS, phosphate-buffered saline; ER, efflux ratio (PappB>A/PappA>B); RR, ratio of ratios; AUC, area under the curve.
- Received June 26, 2007.
- Accepted October 22, 2007.
- The American Society for Pharmacology and Experimental Therapeutics
DMD articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|