M4-Selective mAChR Antagonists for Parkinson's With Fewer Side Effects
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Solution Overview
Problem
Current muscarinic acetylcholine receptor (mAChR) antagonists used for treating Parkinson's disease have dose-limiting adverse effects due to their nonselective action across different subtypes, limiting their clinical efficacy and causing peripheral adverse effects and cognitive disturbances.
Innovation Solution
Development of compounds that selectively target the M4 subtype of mAChR, providing a more targeted approach to antagonize this receptor and potentially reducing adverse effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nonselective mAChR antagonists are used to treat Parkinson's disease, then antiparkinsonian effects are achieved, but peripheral adverse effects and cognitive disturbances occur due to blockade of non-M4 subtypes
Solution Approach 1:
The patent segments the mAChR antagonism function by developing compounds that selectively target only the M4 subtype while sparing other subtypes (M1-M3 and M5). This selectivity is achieved through specific molecular structure design that confers preferential binding to M4 receptors in the basal ganglia, thereby resolving the contradiction by maintaining therapeutic efficacy while eliminating adverse effects associated with nonselective blockade
Solution Approach 2:
The invention applies local quality by creating antagonists with subtype-specific affinity characteristics. The compounds are designed to exhibit high selectivity for M4 receptors in the striatum and other basal ganglia regions, while having minimal affinity for M1-M3 and M5 subtypes in other brain regions and peripheral tissues. This localized selective action maintains antiparkinsonian benefits while avoiding cognitive and peripheral side effects
2Reliability
If doses of nonselective mAChR antagonists are increased to achieve more complete blockade, then antiparkinsonian effects improve, but adverse effects increase and limit clinical utility
Solution Approach 1:
The patent resolves this dose-limitation contradiction by segmenting the receptor subtype targeting, achieving selective M4 blockade that provides sufficient antiparkinsonian efficacy at lower doses. The selective compounds achieve therapeutic effects without the need for high doses that would cause adverse effects, as they specifically target M4 receptors involved in motor control while sparing other subtypes
Solution Approach 2:
The invention changes the selectivity parameter of the antagonists from nonselective to M4-subtype selective. This parameter change allows the use of lower effective doses because the therapeutic effect is concentrated on the relevant M4 receptors without the confounding blockade of other subtypes, thereby improving the therapeutic index and eliminating dose-limiting adverse effects
3Object-affected harmful factors
If selective M4 mAChR antagonists are developed, then adverse effects are minimized, but compound specificity and synthesis complexity increase
Solution Approach 1:
The patent achieves M4 selectivity through local quality modifications in the molecular structure, specifically by incorporating functional groups and structural features that confer preferential binding to M4 receptors. The core structure includes a pyridine ring with specific substituents and a piperazine or similar heterocyclic moiety, with particular spatial arrangement and electronic properties that match the M4 binding site, thereby achieving selectivity without excessive overall molecular complexity
Solution Approach 2:
The invention changes key molecular parameters such as ring substitution patterns, heteroatom placement, and side chain configuration to optimize M4 selectivity. These parameter adjustments are made systematically to achieve the desired receptor specificity while maintaining reasonable synthetic accessibility and avoiding overly complex structures
Data Source
AI summary
Disclosed herein are 1,2,3,4-tetrahydroisoquinolines and 4, 5, 6, 7-tetrahydrothieno [2, 3-cjpyridines, useful as antagonists of the muscarinic acetylcholine receptor M4 (mA·Ch·RM4). Also disclosed herein are methods of making the compounds, pharmaceutical compositions comprising the compounds, and methods of treating disorders using the compounds and compositions.