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Zhang YM, Xu HY, Hu HN, Tian FY, Chen F, Liu HN, Zhan L, Pi XP, Liu J, Gao ZB, Nan FJ. Discovery of HN37 as a Potent and Chemically Stable Antiepileptic Drug Candidate. J Med Chem 2021; 64:5816-5837. [PMID: 33929863 DOI: 10.1021/acs.jmedchem.0c02252] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We previously reported that P-retigabine (P-RTG), a retigabine (RTG) analogue bearing a propargyl group at the nitrogen atom in the linker of RTG, displayed moderate anticonvulsant efficacy. Recently, our further efforts led to the discovery of HN37 (pynegabine), which demonstrated satisfactory chemical stability upon deleting the ortho liable -NH2 group and installing two adjacent methyl groups to the carbamate motif. HN37 exhibited enhanced activation potency toward neuronal Kv7 channels and high in vivo efficacy in a range of pre-clinical seizure models, including the maximal electroshock test and a 6 Hz model of pharmacoresistant limbic seizures. With its improved chemical stability, strong efficacy, and better safety margin, HN37 has progressed to clinical trial in China for epilepsy treatment.
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Affiliation(s)
- Yang-Ming Zhang
- Chinese National Center for Drug Screening, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China.,Yantai Key Laboratory of Nanomedicine & Advanced Preparations, Yantai Institute of Materia Medica, No. 39, Science and Technology Avenue, High-Tech Industrial Development Zone, Yantai City, Shandong 264000, China
| | - Hai-Yan Xu
- Chinese National Center for Drug Screening, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China.,School of Chinese Materia Medica, Nanjing University of Chinese Medicine, 138 Xianlin Avenue, Qixia District, Nanjing City, Jiangsu 210023, China
| | - Hai-Ning Hu
- Chinese National Center for Drug Screening, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Fu-Yun Tian
- Chinese National Center for Drug Screening, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Fei Chen
- Chinese National Center for Drug Screening, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Hua-Nan Liu
- Chinese National Center for Drug Screening, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Li Zhan
- Chinese National Center for Drug Screening, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Xiao-Ping Pi
- Chinese National Center for Drug Screening, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Jie Liu
- Hainan Haiyao Company Ltd., No. 192, Nanhai Road, Xiuying District, Haikou City, Hainan 570311, China
| | - Zhao-Bing Gao
- Chinese National Center for Drug Screening, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China.,School of Chinese Materia Medica, Nanjing University of Chinese Medicine, 138 Xianlin Avenue, Qixia District, Nanjing City, Jiangsu 210023, China
| | - Fa-Jun Nan
- Chinese National Center for Drug Screening, CAS Key Laboratory of Receptor Research, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China.,Yantai Key Laboratory of Nanomedicine & Advanced Preparations, Yantai Institute of Materia Medica, No. 39, Science and Technology Avenue, High-Tech Industrial Development Zone, Yantai City, Shandong 264000, China
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Borgini M, Mondal P, Liu R, Wipf P. Chemical modulation of Kv7 potassium channels. RSC Med Chem 2021; 12:483-537. [PMID: 34046626 PMCID: PMC8128042 DOI: 10.1039/d0md00328j] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 12/01/2020] [Indexed: 01/10/2023] Open
Abstract
The rising interest in Kv7 modulators originates from their ability to evoke fundamental electrophysiological perturbations in a tissue-specific manner. A large number of therapeutic applications are, in part, based on the clinical experience with two broad-spectrum Kv7 agonists, flupirtine and retigabine. Since precise molecular structures of human Kv7 channel subtypes in closed and open states have only very recently started to emerge, computational studies have traditionally been used to analyze binding modes and direct the development of more potent and selective Kv7 modulators with improved safety profiles. Herein, the synthetic and medicinal chemistry of small molecule modulators and the representative biological properties are summarized. Furthermore, new therapeutic applications supported by in vitro and in vivo assay data are suggested.
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Affiliation(s)
- Matteo Borgini
- Department of Chemistry, University of Pittsburgh Pittsburgh PA 15260 USA
| | - Pravat Mondal
- Department of Chemistry, University of Pittsburgh Pittsburgh PA 15260 USA
| | - Ruiting Liu
- Department of Chemistry, University of Pittsburgh Pittsburgh PA 15260 USA
| | - Peter Wipf
- Department of Chemistry, University of Pittsburgh Pittsburgh PA 15260 USA
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Bock C, Surur AS, Beirow K, Kindermann MK, Schulig L, Bodtke A, Bednarski PJ, Link A. Sulfide Analogues of Flupirtine and Retigabine with Nanomolar K V 7.2/K V 7.3 Channel Opening Activity. ChemMedChem 2019; 14:952-964. [PMID: 30861620 DOI: 10.1002/cmdc.201900112] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Indexed: 12/18/2022]
Abstract
The potassium channel openers flupirtine and retigabine have proven to be valuable analgesics or antiepileptics. Their recent withdrawal due to occasional hepatotoxicity and tissue discoloration, respectively, leaves a therapeutic niche unfilled. Metabolic oxidation of both drugs gives rise to the formation of electrophilic quinones. These elusive, highly reactive metabolites may induce liver injury in the case of flupirtine and blue tissue discoloration after prolonged intake of retigabine. We examined which structural features can be altered to avoid the detrimental oxidation of the aromatic ring and shift oxidation toward the formation of more benign metabolites. Structure-activity relationship studies were performed to evaluate the KV 7.2/3 channel opening activity of 45 derivatives. Sulfide analogues were identified that are devoid of the risk of quinone formation, but possess potent KV 7.2/3 opening activity. For example, flupirtine analogue 3-(3,5-difluorophenyl)-N-(6-(isobutylthio)-2-(pyrrolidin-1-yl)pyridin-3-yl)propanamide (48) has 100-fold enhanced activity (EC50 =1.4 nm), a vastly improved toxicity/activity ratio, and the same efficacy as retigabine in vitro.
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Affiliation(s)
- Christian Bock
- Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 17, 17489, Greifswald, Germany
| | - Abdrrahman S Surur
- Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 17, 17489, Greifswald, Germany
| | - Kristin Beirow
- Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 17, 17489, Greifswald, Germany
| | - Markus K Kindermann
- Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 17, 17489, Greifswald, Germany
| | - Lukas Schulig
- Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 17, 17489, Greifswald, Germany
| | - Anja Bodtke
- Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 17, 17489, Greifswald, Germany
| | - Patrick J Bednarski
- Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 17, 17489, Greifswald, Germany
| | - Andreas Link
- Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 17, 17489, Greifswald, Germany
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Abstract
The highly structurally similar drugs flupirtine and retigabine have been regarded as safe and effective for many years but lately they turned out to exert intolerable side effects. While the twin molecules share the mode of action, both stabilize the open state of voltage-gated potassium channels, the form and severity of adverse effects is different. The analgesic flupirtine caused drug-induced liver injury in rare but fatal cases, whereas prolonged use of the antiepileptic retigabine led to blue tissue discoloration. Because the adverse effects seem unrelated to the mode of action, it is likely, that both drugs that occupied important therapeutic niches, could be replaced. Reasons for the clinically relevant toxicity will be clarified and future substitutes for these drugs presented in this review.
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Surur AS, Beirow K, Bock C, Schulig L, Kindermann MK, Bodtke A, Siegmund W, Bednarski PJ, Link A. Flupirtine Analogues: Explorative Synthesis and Influence of Chemical Structure on K V7.2/K V7.3 Channel Opening Activity. ChemistryOpen 2019; 8:41-44. [PMID: 30652063 PMCID: PMC6331712 DOI: 10.1002/open.201800244] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 11/26/2018] [Indexed: 12/19/2022] Open
Abstract
Neuronal voltage‐gated potassium channels KV7.2/KV7.3 are sensitive to small‐molecule drugs such as flupirtine, even though physiological response occurs in the absence of ligands. Clinically, prolonged use of flupirtine as a pain medication is associated with rare cases of drug‐induced liver injury. Thus, safety concerns prevent a broader use of this non‐opioid and non‐steroidal analgesic in therapeutic areas with unmet medical needs such as hyperactive bladder or neonatal seizures. With the goal of studying influences of chemical structure on activity and toxicity of flupirtine, we explored modifications of the benzylamino bridge and the substitution pattern in both rings of flupirtine. Among twelve derivatives, four novel thioether derivatives showed the desired activity in cellular assays and may serve as leads for safer KV channel openers.
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Affiliation(s)
- Abdrrahman S Surur
- Institute of Pharmacy University of Greifswald Friedrich-Ludwig-Jahn-Str. 17 17489 Greifswald Germany
| | - Kristin Beirow
- Institute of Pharmacy University of Greifswald Friedrich-Ludwig-Jahn-Str. 17 17489 Greifswald Germany
| | - Christian Bock
- Institute of Pharmacy University of Greifswald Friedrich-Ludwig-Jahn-Str. 17 17489 Greifswald Germany
| | - Lukas Schulig
- Institute of Pharmacy University of Greifswald Friedrich-Ludwig-Jahn-Str. 17 17489 Greifswald Germany
| | - Markus K Kindermann
- Institute of Pharmacy University of Greifswald Friedrich-Ludwig-Jahn-Str. 17 17489 Greifswald Germany
| | - Anja Bodtke
- Institute of Pharmacy University of Greifswald Friedrich-Ludwig-Jahn-Str. 17 17489 Greifswald Germany
| | | | - Patrick J Bednarski
- Institute of Pharmacy University of Greifswald Friedrich-Ludwig-Jahn-Str. 17 17489 Greifswald Germany
| | - Andreas Link
- Institute of Pharmacy University of Greifswald Friedrich-Ludwig-Jahn-Str. 17 17489 Greifswald Germany
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Surur AS, Bock C, Beirow K, Wurm K, Schulig L, Kindermann MK, Siegmund W, Bednarski PJ, Link A. Flupirtine and retigabine as templates for ligand-based drug design of KV7.2/3 activators. Org Biomol Chem 2019; 17:4512-4522. [DOI: 10.1039/c9ob00511k] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Puzzling stability: molecular jigsaw pieces of residues characterized in light of activity, lipophilicity, stability against oxidation, and hepatotoxicity were combined to yield flupirtine analogue 25b.
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Affiliation(s)
- Abdrrahman S. Surur
- Pharmaceutical and Medicinal Chemistry
- Institute of Pharmacy
- University of Greifswald
- 17487 Greifswald
- Germany
| | - Christian Bock
- Pharmaceutical and Medicinal Chemistry
- Institute of Pharmacy
- University of Greifswald
- 17487 Greifswald
- Germany
| | - Kristin Beirow
- Pharmaceutical and Medicinal Chemistry
- Institute of Pharmacy
- University of Greifswald
- 17487 Greifswald
- Germany
| | - Konrad Wurm
- Pharmaceutical and Medicinal Chemistry
- Institute of Pharmacy
- University of Greifswald
- 17487 Greifswald
- Germany
| | - Lukas Schulig
- Pharmaceutical and Medicinal Chemistry
- Institute of Pharmacy
- University of Greifswald
- 17487 Greifswald
- Germany
| | - Markus K. Kindermann
- Pharmaceutical and Medicinal Chemistry
- Institute of Pharmacy
- University of Greifswald
- 17487 Greifswald
- Germany
| | - Werner Siegmund
- Center of Drug Absorption and Transport (C_DAT) Greifswald
- Germany
| | - Patrick J. Bednarski
- Pharmaceutical and Medicinal Chemistry
- Institute of Pharmacy
- University of Greifswald
- 17487 Greifswald
- Germany
| | - Andreas Link
- Pharmaceutical and Medicinal Chemistry
- Institute of Pharmacy
- University of Greifswald
- 17487 Greifswald
- Germany
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