Current topics in medicinal chemistry
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Since the discovery of rimonabant (Acomplia: 1), a large effort has been directed at the discovery of new, potent and selective CB(1)R antagonists that serve as anti obesity drugs. As a result, a number of compounds reached various stages of clinical trials by late 2008. However, the announcement by Sanofi-Aventis that they were discontinuing all ongoing trials with rimonabant, as a result of the finding that risks associated with depression and anxiety outweighed its benefits, had a major impact on this area. ⋯ Various approaches have been employed to design these analogs, such as bioisosteric replacement, introduction of conformational constraints, scaffold hopping and ligand-based molecular modeling. In addition, current approaches that have been uncovered to avoid psychiatric side effects of CB(1)R antagonists are summarized. Finally, the design of non-brain penetrating and peripherally acting CB(1)R antagonists, allosteric modulators of CB(1)R, and neutral antagonists for CB(1)R is also discussed in this review.
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The voltage-gated sodium channels (VGSCs) play a fundamental role in controlling cellular excitability. Abnormal activity of sodium channels is related to several pathological processes, including cardiac arrhythmias, epilepsy, chronic pain, neurodegenerative diseases and spasticity. In view of this, VGSCs are considered important therapeutic targets for the treatment of these disorders. ⋯ In addition, VGSCs also have distinct electrophysiological profiles with differing activation and inactivation states. As such, there is a concerted effort to develop not only isoform selective antagonists, but also antagonists that exhibit state selectivity, particularly to the inactivated state of the channel. This review will provide a brief historical prospective and will primarily focus on recent advances in the development of isoform specific and state selective sodium channel antagonists and the medicinal chemistry involved, surveying the emerging therapeutic fields.
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The voltage-gated sodium channels are a family of proteins that control the flow of sodium ions across cell membranes. Considerable data support the hypothesis that hyperexcitability and spontaneous action potential firing in peripheral sensory neurons mediated by voltage-gated sodium channels contribute to the pathophysiology of chronic pain. Sodium channel blockers are, therefore, appealing entities for therapeutic intervention in painful human neuropathies. This review will focus on the latest advances in the development of small molecule sodium channel blockers and their application to the treatment of chronic pain.
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Inhibitors of dipeptidyl peptidase IV (DPP-4) have emerged as an important new class of therapeutic agents for type two diabetes. Various medicinal chemistry approaches have been applied to this area and have resulted in the identification of numerous late-stage development compounds. The discoveries of several of the most advanced DPP-4 inhibitors are reviewed.
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NMDA receptors are known to be involved in nociceptive transmission and pain processing. Many structurally diverse NMDA antagonists have been reported to have activity in both animal models and clinical models of neuropathic pain. ⋯ These types of compounds may hold potential promise for future pain therapies. This review covers reported pain data surrounding representative examples of NMDA antagonists and provides a current assessment of potential clinical utility.