Pyrazole-Indole Conjugates for Photodynamic Therapy
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Solution Overview
Problem
Current photodynamic therapy (PDT) agents face challenges in achieving low dark toxicity while maintaining strong photocytotoxicity and selectivity towards target cells, such as cancer and bacterial cells, due to limitations in wavelength absorbance and cellular specificity.
Innovation Solution
Development of novel conjugated pyrazole-indole derivatives with specific linker structures and substituents, which exhibit photodynamic properties and low dark toxicity, allowing for their use as anticancer and antibacterial agents when activated by light, particularly in the 400-450 nm wavelength range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photosensitizers (porphyrins, chlorins, bacteriochlorins, phthalocyanines) are used for photodynamic therapy, then strong photocytotoxicity is achieved, but high dark toxicity and limited wavelength absorbance occur
Solution Approach 1:
The patent changes the chemical structure parameters by using pyrazole-indole conjugates with extended π-conjugation systems instead of conventional porphyrinoid structures. This structural parameter change results in red-shifted absorption spectra (400-450 nm range) and reduced dark toxicity while maintaining photocytotoxicity, directly resolving the contradiction between strong photocytotoxicity and low dark toxicity
Solution Approach 2:
The patent creates composite molecular structures by conjugating pyrazole and indole units with various linker groups (-CH=CH-, -CH=CH-CH=CH-, -C≡C-). This composite approach combines the photodynamic properties of extended conjugation with the biochemical compatibility of nitrogen-containing heterocycles, achieving both strong photocytotoxicity and low dark toxicity simultaneously
2Use of energy by moving object
If photosensitizers with extended π-conjugation are designed to achieve long-wavelength absorbance, then wavelength range is improved, but molecular complexity and synthesis difficulty increase
Solution Approach 1:
The patent segments the photosensitizer molecule into modular components: pyrazole unit, linker group (-CH=CH-, -CH=CH-CH=CH-, or -C≡C-), and indole unit. This segmentation allows systematic variation of the linker to tune wavelength absorbance while maintaining a relatively simple core structure, reducing overall molecular complexity compared to conventional approaches
Solution Approach 2:
The patent changes the conjugation length parameter by selecting different linker groups (-CH=CH- for shorter, -CH=CH-CH=CH- for intermediate, -C≡C- for shorter). This parameter change approach enables precise control over wavelength absorbance (400-450 nm range) while keeping the molecular structure relatively simple and synthetically accessible
3Adaptability or versatility
If conventional photosensitizers are used for cancer treatment, then broad applicability is achieved, but selectivity towards target cells is insufficient
Solution Approach 1:
The patent applies local quality by incorporating specific substituent groups (R1-R6) at defined positions on the pyrazole-indole core structure. These local structural modifications can be tailored to enhance selectivity towards cancer cells and bacteria while maintaining broad photodynamic applicability, resolving the contradiction between versatility and selectivity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
These derivatives demonstrate effective cell death induction and antimicrobial activity, with minimal dark cytotoxicity, making them suitable for treating various cancers and bacterial infections through targeted photodynamic therapy.
Implementation Method 1
Photodynamic therapy (PDT) is a non-surgical, minimally invasive treatment which uses light-sensitive medication (photosensitizer, PS), light source and oxygen to produce cytotoxic reactive oxygen species (ROS), which in turn cause abnormal cell destruction
Data Source
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AI summary
The present invention relates to new pyrazole-indole derivatives conjugated by ethene, buta-1,3-diene or ethyne linkers and containing substituents at R1, R2 and R3 positions of the general formula I which can be used in photodynamic therapy of cancer or bacterial infections. The invention further includes pharmaceutical compositions containing the conjugated pyrazole-indoline derivatives. (I)