Metal Thiourea Complexes for Stable Metal Ion Delivery
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Solution Overview
Problem
Coinage metal ions, such as Au, Ag, and Cu, are unstable under physiological conditions, limiting their therapeutic applications, and existing ligands like phosphine are cytotoxic, while biological studies on metal-thiourea complexes are sparse.
Innovation Solution
Development of metal thiourea complexes with N,N′-disubstituted cyclic thiourea ligands, specifically Au(I), Ag(I), and Cu(I) complexes, which form stable compounds that exhibit potent cytotoxicity against cancer cells by inhibiting thioredoxin reductase, an enzyme crucial in cancer progression and inflammatory diseases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If naked coinage metal ions (Au+, Ag+, Cu+) are used as therapeutic agents, then they exhibit distinct biological activities for anti-arthritis, antimicrobial, and anti-cancer treatment, but they are unstable under physiological conditions due to precipitation, aerobic oxidation and reduction
Solution Approach 1:
The patent introduces auxiliary ligands (thiourea and its derivatives) as intermediaries that coordinate with coinage metal ions to form stable complexes. These ligands act as mediators that prevent direct interaction between metal ions and physiological environments, thereby maintaining stability while preserving biological activity. The thiourea ligands with specific substituents (R1, R2, n) are designed to optimize both stability and bioactivity.
Solution Approach 2:
The patent creates composite structures by combining coinage metal ions with thiourea ligands to form metal-thiourea complexes. This composite approach integrates the beneficial biological properties of metal ions with the stabilizing properties of organic ligands, resulting in compounds that exhibit both enhanced stability and therapeutic activity.
2Stability of the object's composition
If phosphine ligands are used to develop bioactive d10 metal compounds, then stability is improved, but cytotoxicity increases
Solution Approach 1:
The patent changes the chemical parameters of the ligand system by replacing phosphine with thiourea and its derivatives. This parameter change involves modifying the donor atoms (from P to S/N), steric properties, and electronic characteristics of the ligand, thereby altering the biological profile of the metal complex while maintaining stability. The specific substitution patterns on thiourea (R1, R2 groups) are optimized to reduce cytotoxicity.
Solution Approach 2:
The patent employs thiourea ligands that can be designed with pharmacophores that are metabolically labile, allowing the complex to release the active metal ion at the target site while the ligand framework is eventually degraded and excreted, reducing long-term accumulation and chronic cytotoxicity.
3Adaptability or versatility
If metal-thiourea complexes are developed for biological studies, then new therapeutic agents can be discovered, but biological studies on such complexes are sparse
Solution Approach 1:
The patent segments the therapeutic agent into distinct functional components: the coinage metal ion (Au+, Ag+, Cu+) provides the primary biological activity, while the thiourea ligand (with variable R1, R2, n substituents) provides stability and can be optimized for specific target recognition. This segmentation allows independent optimization of each component and facilitates structure-activity relationship studies.
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
The metal thiourea complexes demonstrate significant cytotoxicity against cancer cells with low micromolar concentrations, achieving potent inhibition of thioredoxin reductase and glutathione peroxidase, offering a new paradigm for bioactive metal-based therapeutic agents.
Implementation Method 1
gold(I) thiourea complex exhibits potent tight-binding inhibition of anticancer drug target thioredoxin reductase
Data Source
AI summary
The present invention relates to metal thiourea complexes comprising N-substituted thiourea ligands and sulfur-coordinated metal ions, and methods for using the metal thiourea complexes for delivering otherwise unstable or impermeable metal ions to mammalian cells, for inhibiting cancer cell growth and inflammation, and for inhibiting the activities of associated drug targets under in vitro and in vivo conditions. The metal complexes of N-substituted thiourea are defined by the following formula (Ia or Ib) wherein R1 can be H, alkyl, alkenyl, alkynyl, aryl or heterocyclic groups; R2 can be H, alkyl, alkenyl, alkynyl or aryl groups; n=1 to 4; X− is a pharmaceutically acceptable anion (chloride, bromide, iodide, hexafluorophosphate, or triflate) and M is a coinage metal (Au, Ag, or Cu).