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An ex Vivo Model for Evaluating Blood-Brain Barrier Permeability, Efflux, and Drug Metabolism.

Hellman, Karin LU ; Aadal Nielsen, Peter; Ek, Fredrik LU and Olsson, Roger LU (2016) In ACS Chemical Neuroscience
Abstract
The metabolism of drugs in the brain is difficult to study in most species because of enzymatic instability in vitro and interference from peripheral metabolism in vivo. A locust ex vivo model that combines brain barrier penetration, efflux, metabolism, and analysis of the unbound fraction in intact brains was evaluated using known drugs. Clozapine was analyzed, and its major metabolites, clozapine N-oxide (CNO) and N-desmethylclozapine (NDMC), were identified and quantified. The back-transformation of CNO into clozapine observed in humans was also observed in locusts. In addition, risperidone, citalopram, fluoxetine, and haloperidol were studied, and one preselected metabolite for each drug was analyzed, identified, and quantified.... (More)
The metabolism of drugs in the brain is difficult to study in most species because of enzymatic instability in vitro and interference from peripheral metabolism in vivo. A locust ex vivo model that combines brain barrier penetration, efflux, metabolism, and analysis of the unbound fraction in intact brains was evaluated using known drugs. Clozapine was analyzed, and its major metabolites, clozapine N-oxide (CNO) and N-desmethylclozapine (NDMC), were identified and quantified. The back-transformation of CNO into clozapine observed in humans was also observed in locusts. In addition, risperidone, citalopram, fluoxetine, and haloperidol were studied, and one preselected metabolite for each drug was analyzed, identified, and quantified. Metabolite identification studies of clozapine and midazolam showed that the locust brain was highly metabolically active, and 18 and 14 metabolites, respectively, were identified. The unbound drug fraction of clozapine, NDMC, carbamazepine, and risperidone was analyzed. In addition, coadministration of drugs with verapamil or fluvoxamine was performed to evaluate drug-drug interactions in all setups. All findings correlated well with the data in the literature for mammals except for the stated fact that CNO is a highly blood-brain barrier permeant compound. Overall, the experiments indicated that invertebrates might be useful for screening of blood-brain barrier permeation, efflux, metabolism, and analysis of the unbound fraction of drugs in the brain in early drug discovery. (Less)
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author
organization
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Contribution to journal
publication status
published
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in
ACS Chemical Neuroscience
publisher
The American Chemical Society
external identifiers
  • PMID:26930271
  • Scopus:84969813076
ISSN
1948-7193
DOI
10.1021/acschemneuro.6b00024
language
English
LU publication?
yes
id
3a74d043-1bbf-4260-ab98-087800f85dff (old id 8856709)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/26930271?dopt=Abstract
date added to LUP
2016-03-15 10:52:59
date last changed
2016-10-13 04:32:25
@misc{3a74d043-1bbf-4260-ab98-087800f85dff,
  abstract     = {The metabolism of drugs in the brain is difficult to study in most species because of enzymatic instability in vitro and interference from peripheral metabolism in vivo. A locust ex vivo model that combines brain barrier penetration, efflux, metabolism, and analysis of the unbound fraction in intact brains was evaluated using known drugs. Clozapine was analyzed, and its major metabolites, clozapine N-oxide (CNO) and N-desmethylclozapine (NDMC), were identified and quantified. The back-transformation of CNO into clozapine observed in humans was also observed in locusts. In addition, risperidone, citalopram, fluoxetine, and haloperidol were studied, and one preselected metabolite for each drug was analyzed, identified, and quantified. Metabolite identification studies of clozapine and midazolam showed that the locust brain was highly metabolically active, and 18 and 14 metabolites, respectively, were identified. The unbound drug fraction of clozapine, NDMC, carbamazepine, and risperidone was analyzed. In addition, coadministration of drugs with verapamil or fluvoxamine was performed to evaluate drug-drug interactions in all setups. All findings correlated well with the data in the literature for mammals except for the stated fact that CNO is a highly blood-brain barrier permeant compound. Overall, the experiments indicated that invertebrates might be useful for screening of blood-brain barrier permeation, efflux, metabolism, and analysis of the unbound fraction of drugs in the brain in early drug discovery.},
  author       = {Hellman, Karin and Aadal Nielsen, Peter and Ek, Fredrik and Olsson, Roger},
  issn         = {1948-7193},
  language     = {eng},
  month        = {03},
  publisher    = {ARRAY(0xb442e70)},
  series       = {ACS Chemical Neuroscience},
  title        = {An ex Vivo Model for Evaluating Blood-Brain Barrier Permeability, Efflux, and Drug Metabolism.},
  url          = {http://dx.doi.org/10.1021/acschemneuro.6b00024},
  year         = {2016},
}