Related Experiment Video
Updated: May 5, 2026

Setting-up an In Vitro Model of Rat Blood-brain Barrier BBB: A Focus on BBB Impermeability and Receptor-mediated Transport
Published on: June 28, 2014
Improved Delivery Through Biological Membranes. XXIV. Synthesis, in Vitro Studies, and in Vivo Characterization of
M E Brewster1, K S Estes, N Bodor
1Pharmatec, Inc, 730, Alachua, Florida, 32615.
Abstract:
Dihydropyridine ⇄ pyridinium salt-based brain-selective delivery systems were synthesized for the progestins, ethisterone, norethindrone, and norgestrel. After initial lipophilicity and in vitro studies indicated the feasibility of applying these compounds to brain-specific delivery, in vivo distribution studies were performed on one of the redox delivery systems. After systemic administration of the chemical delivery system based on norethindrone, sustained and selective delivery of the oxidized form of the drug-carrier complex was observed in the brain. In addition, a slow and sustained release of the parent steroid, norethindrone, occurred. This release produced substantially higher levels of norethindrone for more prolonged periods than the administration of norethindrone itself.
More Related Videos
Related Concept Videos
Intrauterine Drug Delivery Systems
Prodrugs
Prodrugs help overcome...
Bioavailability Enhancement: Drug Stability Enhancement and GI Retention
Modified-Release Drug Delivery Systems: Site-Targeted
Oral Drug Delivery Systems: Continuous-Release Systems
Site-Targeted Drug Delivery Systems: Polymeric Carriers

