Tricyclic MR Ligands for Selective Mineralocorticoid Antagonism
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Solution Overview
Problem
Current mineralocorticoid receptor (MR) antagonists, such as spironolactone and eplerenone, have limitations including nonselectivity, side effects like hyperkalemia, and cardiac risks due to hERG channel blockade, necessitating the development of nonsteroidal MR ligands with improved affinity and reduced toxicity.
Innovation Solution
Development of novel tricyclic MR ligands, as represented by Formula (I), which exhibit enhanced affinity for MR over other nuclear hormone receptors and possess potent reno- and cardio-protective activities with a reduced incidence of hyperkalemia and hERG channel blockade.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spironolactone is used as an MR antagonist, then MR blocking activity is achieved, but nonselectivity occurs causing cross-reaction with other nuclear hormone receptors (AR, PR, GR)
Solution Approach 1:
The patent applies local quality by designing the tricyclic compound structure with specific functional groups positioned to interact selectively with the MR binding pocket. The dibenzoxepine core structure with particular substituent patterns (R1, R2, R3, R4, R5, R6, R7, R8) creates a localized molecular environment that fits MR with high affinity while excluding AR, PR, and GR through steric and electronic complementarity specific to MR's binding site architecture.
Solution Approach 2:
The patent employs parameter changes by systematically varying the chemical structure parameters of the tricyclic compounds, including different substituent groups at positions R1-R8, to optimize the balance between MR affinity and selectivity. By adjusting these molecular parameters, the compounds achieve enhanced MR blocking activity while reducing off-target effects on other nuclear hormone receptors compared to spironolactone.
2Reliability
If existing MR antagonists are used, then treatment efficacy is achieved, but hyperkalemia occurs as a side effect
Solution Approach 1:
The patent applies the taking out principle by extracting the essential MR antagonistic pharmacological effect from the problematic steroid hormone structure of spironolactone and eplerenone. The nonsteroidal tricyclic compounds isolate the desired MR blocking activity while eliminating the steroid core structure that is associated with hyperkalemia and other adverse effects, thereby achieving efficacy without the harmful metabolic consequences.
Solution Approach 2:
The patent employs disposable principles by creating a new class of nonsteroidal compounds that do not rely on the persistent steroid hormone structure. These tricyclic compounds provide transient but effective MR antagonism without the long-term metabolic disruptions caused by steroid-based antagonists, reducing the risk of chronic hyperkalemia.
3Reliability
If conventional MR antagonists are administered, then cardiovascular protection is provided, but hERG channel blockade occurs leading to cardiac arrhythmias
Solution Approach 1:
The patent applies inversion by reversing the structural approach: instead of modifying existing steroid-based MR antagonists that inadvertently block hERG channels, the invention inverts to a completely nonsteroidal tricyclic framework. This structural inversion eliminates the planar aromatic systems and other features in conventional antagonists that are prone to hERG interaction, while preserving MR antagonistic activity through the dibenzoxepine core.
4Reliability
If nonsteroidal MR ligands are developed, then affinity for MR is improved, but structural complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the molecular structure into distinct functional segments: the dibenzoxepine core structure provides the primary MR binding interaction, while separate substituent groups at R1-R8 positions provide secondary interactions and fine-tune affinity. This segmented design allows optimization of each segment independently to achieve high overall affinity without excessive overall molecular complexity.
Data Source
AI summary
The present invention provides a compound of Formula (I): or a pharmaceutically acceptable salt thereof; pharmaceutical compositions comprising a compound of Formula (I) in combination with a suitable carrier, diluent, or excipient; and methods for treating physiological disorders, particularly congestive heart failure, hypertension, diabetic nephropathy, or chronic kidney disease, comprising administering a compound of Formula (I), or a pharmaceutically acceptable salt thereof.