Phthalazinone PARP Inhibitors With Potent Low-Concentration Activity
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Solution Overview
Problem
Existing PARP inhibitors suffer from weak inhibitory activity and lack desirable pharmaceutical properties, limiting their clinical applications in conditions where PARP is implicated, such as cancer, inflammatory diseases, and ischemic conditions.
Innovation Solution
Development of phosphorous containing heterocyclic compounds, particularly phthalazin-1(2H)-one derivatives, which act as potent inhibitors of PARP enzymes with improved pharmaceutical properties, capable of inhibiting PARP-1 enzymatic activity and intracellular poly(ADP-ribose) formation at low concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If known PARP inhibitors (nicotinamide analogues such as benzamide derivatives) are used, then they interact with the nicotinamide binding domain of the enzyme, but they exhibit weak inhibitory activity or lack desirable pharmaceutical properties
Solution Approach 1:
The patent changes the chemical structure parameters by replacing the nicotinamide analogue scaffold with a phthalazin-1(2H)-one core structure, and modifies substituent parameters (R1-R6, Ar1-Ar6) to optimize both inhibitory activity and pharmaceutical properties. This structural parameter change resolves the contradiction by achieving potent inhibition (IC50 < 100 nM) while maintaining desirable pharmaceutical properties for clinical use.
2Device complexity
If amide or aryl substituted 4-benzyl-2H-phthalazin-1-one derivatives are used as PARP inhibitors, then they show improved structure-based design, but many still suffer from weak inhibitory activity
Solution Approach 1:
The patent applies local quality by specifically optimizing the substituent groups at different positions of the phthalazin-1(2H)-one core. Different R groups (R1-R6) and Ar groups (Ar1-Ar6) are designed with specific properties (halo, alkyl, alkoxy, aryl, heteroaryl) to enhance binding affinity at the nicotinamide binding domain, achieving potent inhibitory activity through localized structural optimization.
Solution Approach 2:
The patent creates composite molecular structures by combining the phthalazin-1(2H)-one core with various substituent groups (amide, aryl, heteroaryl) to design compounds with optimized properties. This composite approach allows integration of multiple functional groups that collectively achieve both high inhibitory activity and desirable pharmaceutical properties.
3Reliability
If PARP inhibition is achieved to treat cancer and inflammatory diseases, then enzymatic activity is suppressed, but pharmaceutical properties must be maintained for clinical application
Solution Approach 1:
The patent systematically varies molecular parameters (core structure, substituent types, positions) to find the optimal balance between enzymatic inhibition efficacy and pharmaceutical properties. The phthalazin-1(2H)-one scaffold with specific R and Ar group combinations achieves IC50 < 100 nM while maintaining properties suitable for clinical development.
Data Source
AI summary
The invention provides for compositions comprising phosphorous containing tricyclic compounds, including phthalazin-1(2H)-one derivatives. The compounds are potent inhibitors of the enzyme poly(ADP-ribose)polymerase (PARP), particularly PARP-1 and potentially PARP-2. The also show good cellular activity in inhibiting poly(ADP-ribose) oligomer formation. The compounds may be useful as mono-therapy or in combination with other therapeutic agents in the treatment conditions where PARP is implicated, such as cancer, inflammatory diseases and ischemic conditions. Thus, also provided are methods for the treatment of a condition where PARP is implicated comprising administering to an effective amount of a compound of the invention to an individual in need thereof.