Selective M4 Muscarinic Receptor Antagonists for Extrapyramidal Symptom Management
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Solution Overview
Problem
Current treatments for neurological disorders such as Tourette's syndrome, Alzheimer's Disease, and schizophrenia often cause extrapyramidal symptoms due to lack of selectivity in muscarinic receptor antagonism, leading to undesirable side effects.
Innovation Solution
Development of 2-azaspiro[3.3]heptane derivatives that selectively modulate the muscarinic acetylcholine receptor M4, providing a therapeutic option for these conditions without affecting other receptor subtypes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If classical muscarinic receptor antagonists (atropine, scopolamine, QNB) are used to treat neurological disorders, then extrapyramidal symptoms can be managed, but selectivity for specific receptor subtypes is lost leading to use-limiting side effects
Solution Approach 1:
The patent applies local quality by designing compounds with specific structural features (2-azaspiro[3.3]heptane core with particular substituent patterns) that confer selective affinity for M4 receptors over other muscarinic subtypes. This selective binding profile allows the drug to act locally on M4 receptors in the brain while sparing other muscarinic receptors, thereby treating extrapyramidal symptoms without causing the cognitive impairment, tachycardia, and gastrointestinal side effects associated with non-selective antagonism
Solution Approach 2:
The patent employs parameter changes by systematically modifying molecular parameters (substituent types, positions, and configurations on the 2-azaspiro[3.3]heptane scaffold) to optimize selectivity for M4 receptors. By adjusting these chemical parameters, the compounds achieve differential binding affinities across muscarinic receptor subtypes, with particular emphasis on high selectivity for M4 over M1, M2, M3, and M5 receptors, thus resolving the contradiction between therapeutic effectiveness and side effect profile
2Reliability
If non-selective anticholinergic drugs are used to treat parkinsonism or dystonia, then motor symptoms can be alleviated, but cognitive impairment and other side effects occur due to antagonism of M1, M2, and M3 receptors
Solution Approach 1:
The patent applies local quality by engineering compounds with selective M4 receptor affinity through specific structural characteristics of the 2-azaspiro[3.3]heptane framework. This selectivity enables the drug to target M4 receptors in the striatum and other brain regions involved in motor control, providing therapeutic benefit for parkinsonism and dystonia while avoiding antagonism of M1 receptors in the cortex (which would cause cognitive impairment) and M2/M3 receptors in the heart and gastrointestinal tract
Solution Approach 2:
The patent applies segmentation by dividing the muscarinic receptor population into distinct subtypes and selectively targeting only the M4 subtype. This segmentation approach allows the therapeutic action to be confined to M4-mediated pathways involved in motor function, while leaving other muscarinic receptor systems intact, thereby eliminating the need to trade off motor symptom relief against cognitive and gastrointestinal side effects
Data Source
AI summary
The present invention relates to compounds of Formula (Ia), pharmaceutically acceptable salts of compounds of Formula (Ia), and pharmaceutical compositions thereof that modulate the activity of the muscarinic acetylcholine receptor M4. Compounds, pharmaceutical salts of compounds, and pharmaceutical compositions of the present invention are directed to methods useful in the treatment or prophylaxis of a neurological disease, disorder, or symptom, and conditions related thereto.