Optimization of Blood-Brain Barrier Permeability with Potent and Selective Human Neuronal Nitric Oxide Synthase Inhibitors Having a 2-Aminopyridine Scaffold.
Do, H.T., Li, H., Chreifi, G., Poulos, T.L., Silverman, R.B.(2019) J Med Chem 62: 2690-2707
- PubMed: 30802056 
- DOI: https://doi.org/10.1021/acs.jmedchem.8b02032
- Primary Citation of Related Structures:  
6NG1, 6NG2, 6NG4, 6NG5, 6NG6, 6NG7, 6NG8, 6NGA, 6NGB, 6NGC, 6NGD, 6NGE, 6NGF, 6NGH, 6NGI, 6NGJ, 6NGK, 6NGL, 6NGM, 6NGN, 6NGP, 6NGQ, 6NGR, 6NGS, 6NGT, 6NGU, 6NGV, 6NGW, 6NGX, 6NGY, 6NGZ, 6NH0, 6NH1, 6NH2, 6NH3, 6NH4, 6NH5, 6NH6, 6NH7, 6NH8, 6NHB, 6NHC, 6NHD, 6NHE, 6NHF - PubMed Abstract: 
Effective delivery of therapeutic drugs into the human brain is one of the most challenging tasks in central nervous system drug development because of the blood-brain barrier (BBB). To overcome the BBB, both passive permeability and efflux transporter liability of a compound must be addressed. Herein, we report our optimization related to BBB penetration of neuronal nitric oxide synthase (nNOS) inhibitors toward the development of new drugs for neurodegenerative diseases. Various approaches, including enhancing lipophilicity and rigidity of new inhibitors and modulating the p K a of amino groups, have been employed. In addition to determining inhibitor potency and selectivity, crystal structures of most newly designed compounds complexed to various nitric oxide synthase isoforms have been determined. We have discovered a new analogue (21), which exhibits not only excellent potency ( K i < 30 nM) in nNOS inhibition but also a significantly low P-glycoprotein and breast-cancer-resistant protein substrate liability as indicated by an efflux ratio of 0.8 in the Caco-2 bidirectional assay.
Organizational Affiliation: 
Department of Chemistry, Department of Molecular Biosciences, Chemistry of Life Processes Institute, Center for Molecular Innovation and Drug Discovery, Center for Developmental Therapeutics , Northwestern University , 2145 Sheridan Road , Evanston , Illinois 60208-3113 , United States.