Search Results (11)

Nonsteroidal anti-inflammatory drugs such as phenylbutazone (PBZ) are among the most widely used medications globally due to their effectiveness in relieving pain and reducing inflammation. This study aims to detect PBZ with metallic particle-based electrochemical sensors using cyclic voltammetry (CV) in the presence of catechol as a redox probe. The approach focuses on evaluating the electrochemical behaviour of PBZ under different experimental conditions and optimizing the detection parameters to develop a simple, rapid, and cost-effective analytical method suitable for this pharmaceutical compound in lab practice. CV was performed using four types of screen-printed electrodes, each modified with different transitional metal particles, in potassium ferrocyanide/potassium ferricyanide, catechol, and catechol-PBZ solutions to study the electrochemical response and detection capability for PBZ. The best performance characteristics were obtained for the sensor modified with Ir particles that detect PBZ, with a linearity range of 0.01 to 1.00 μM and a detection limit of 1.53 nM. Additionally, Fourier-transform infrared spectroscopy (FT-IR) was used to characterize the PBZ in pharmaceuticals. The method using an iridium-modified sensor developed in this study allows the accurate detection of PBZ in pharmaceuticals with a relative error lower than 4%. Full article

This review paper presents a comprehensive literature analysis that elucidates the global engagement of research teams in addressing the important problem of finding effective oncology drugs based on the following platinum group metal ions: ruthenium, rhodium and iridium. The necessity to search for new drugs can be attributed, in part, to the predominance of platinum-based chemotherapeutics in clinical practice. However, these drugs face limitations in their clinical application due to their inherent toxicity and the development of resistance by cancer cells. A distinctive attribute of these metal compounds is the formation of diamagnetic stable complexes on +II (Ru) and +III (Rh, Ir) oxidation degrees with a d⁶ electron configuration, a coordination number of six and an octahedral or pseudo-octahedral structure. In this paper we have systematised the findings presented in the literature by classifying the most significant categories of ruthenium, rhodium and iridium compounds, namely piano-stool-type arenes, polypyridine and cyclometalated complexes, dimers and multinuclear complexes. Additionally, the most crucial research challenges connected with metal complexes that have been addressed by scientists have been presented: (i) the application of prodrugs in cancer therapy; (ii) the deployment of complexes as sensitizers in PDT and PACT; (iii) the exploration of complexes as inhibitors of enzymes and biocatalysts; and (iv) the investigation of multiple-target complexes. Furthermore, the objective was to emphasise the accomplishments in this domain in recent years by identifying compounds that have entered the clinical trial phase. Full article

Towards the efforts to expand the bioactivity and to reduce toxic and adverse properties of known metal-based drugs, various multinuclear complexes have recently been studied. They have shown enhancement of target specificity and selectivity. Different from small organic compounds and traditional metal-based complexes with anticancer activity, iridium(III) multinuclear or heteronuclear metallodrugs have confirmed potential advantages due to their unique biological and chemical diversities, better activity and different anticancer mechanisms. Ir(III) coordination compounds, similar to most Pt group compounds, are of excessive interest because of their potential cytotoxic activity, effective cellular uptake and tolerance by healthy cells. Although mononuclear Ir(III) complex compounds have been extensively studied as promising candidates for antitumor application, the research on the antineoplastic potential of homo- or hetero-multinuclear iridium(III) complexes is not as abundant; nevertheless, intensive investigations have been conducted in the recent years towards developing complexes that are anticipated to have improved therapeutic potential and biotarget selectivity. Multimetallic iridium(III) frameworks have offered interesting possibilities for designing new antitumor agents by exploiting the action of different metal cations at the same time. This method was very successful in the design of homo- and hetero-multinuclear cyclometalated and half-sandwich organometallic Ir(III) compounds. In the described background, many homonuclear and heteronuclear Ir(III) complexes have been estimated and have exposed promising advantages in cancer therapy. This review intends to summarize newly reported innovative and promising multinuclear Ir(III)-based complexes and to afford a wide-ranging overview of current development and perspectives for the practical impact of these complexes in the tumor therapy field. It is anticipated that this analysis will provide significant direction for the further progress of active homonuclear and heteronuclear iridium-based anticancer agents. Full article

Approaches capable of simultaneously treating cancer and protecting susceptible patients from lethal infections are highly desirable, although they prove challenging. Taking inspiration from the well-known anticancer platinum complexes, successive studies about the complexation of organic compounds with other late transition metals, such as silver, gold, palladium, rhodium, ruthenium, iridium, and osmium, have led to remarkable anticancer activities. Among the numerous chemical moieties studied, N-heterocyclic carbenes (NHCs) have revealed very attractive activities due to their favorable chemical properties. Specifically, gold–NHC complexes emerged as some of the most active complexes acting as antitumor agents. On the other hand, some recent studies have highlighted the involvement of these complexes in antiviral research as well. The well-known gold-based, orally available complex auranofin approved by the Food and Drug Administration (FDA) for the treatment of rheumatoid arthritis has been suggested as a repositioned drug for both cancer and viral infections. In the era of the COVID-19 pandemic, the most interesting goal could be the discovery of gold–NHC complexes as dual antiviral and anticancer agents. In this review, the most recent studies regarding the anticancer and antiviral activities of gold(I)–NHC complexes will be analyzed and discussed, offering an interesting insight into the research in this field. Full article

Iridium complexes attract a lot of attention as highly promising antitumor agents due to their various structures, which offer the modification of their physicochemical and biological effects. Compared to conventional platinum-based drugs, iridium complexes are commonly thought to be more active in tumors, resistant to platinum agents and more stable in air and moisture conditions. Chloridoiridium complexes offer a range of advantages facilitating their rational design, reactivity and photochemical activity, leading to different cytotoxic profiles, diverse mechanisms of action and specific intracellular organelles as targets. They are also known as good light-mediated chemotherapeutics, serving as bioimaging and biosensing agents. The potential biological and photophysical properties of chloridoiridium(III) complexes can be readily controlled by suitable ligand modifications and substitution patterns, providing a wide range of versatile structures. Over the years, numerous different structural types of chloridoiridium complexes have been developed and studied for their antineoplastic activity. In this review, the recent advances in the cytotoxicity studies of chloridoiridium(III) compounds have been summarized. The studied complexes have been categorized in this review according to the number of coordinated ligands, the type of donor atoms, nuclearity of the complexes, etc., allowing for a thorough discussion of the structure–activity relationship. Full article

The aim of this work is to incorporate lanthanide-cored upconversion nanoparticles (UCNP) into the surface of microengineered biomedical implants to create a spatially controlled and optically releasable model drug delivery device in an integrated fashion. Our approach enables silicone-based microelectrocorticography (ECoG) implants holding platinum/iridium recording sites to serve as a stable host of UCNPs. Nanoparticles excitable in the near-infrared (lower energy) regime and emitting visible (higher energy) light are utilized in a study. With the upconverted higher energy photons, we demonstrate the induction of photochemical (cleaving) reactions that enable the local release of specific dyes as a model system near the implant. The modified ECoG electrodes can be implanted in brain tissue to act as an uncaging system that releases small amounts of substance while simultaneously measuring the evoked neural response upon light activation. In this paper, several technological challenges like the surface modification of UCNPs, the immobilization of particles on the implantable platform, and measuring the stability of integrated UCNPs in in vitro and in vivo conditions are addressed in detail. Besides the chemical, mechanical, and optical characterization of the ready-to-use devices, the effect of nanoparticles on the original electrophysiological function is also evaluated. The results confirm that silicone-based brain–machine interfaces can be efficiently complemented with UCNPs to facilitate local model drug release. Full article

An inexpensive and highly efficient metal-free alternative to commonly used Ru- and Ir-based catalysts was proposed. It was shown that the new 2,7-di-tert-butyl-5,10-bis(4-trifluoromethylphenyl)-5,10-dihydrophenazine outcompeted the iridium phenylpyridyl complex in photoredox activity in the alkylation of silyl enol ethers yielding aryl alkyl ketones. The reaction occurred under visible light irradiation at room temperature and was also applicable to drug derivatives (ibuprofen and naproxen). In-depth photophysical, electrochemical, and quantum chemical studies showed that the aforementioned N,N-diaryldihydrophenazine exhibited enhanced properties that were essential for the photoredox catalysis (a long-lived triplet excited state, strong reducing ability, high stability of the radical cations formed in single-electron-transfer event, and chemical inertness of the catalyst with respect to reactants). Importantly, the substituted N,N′-diaryldihydrophenazines could be obtained directly from diaryl amines; a facile, easily handled and scaled-up one-pot synthetic procedure was elaborated. Full article

Countless expectations converge in the multidisciplinary endeavour for the search and development of effective and safe drugs in fighting cancer. Although they still embody a minority of the pharmacological agents currently in clinical use, metal-based complexes have great yet unexplored potential, which probably hides forthcoming anticancer drugs. Following the historical success of cisplatin and congeners, but also taking advantage of conventional chemotherapy limitations that emerged with applications in the clinic, the design and development of non-platinum metal-based chemotherapeutics, either as drugs or prodrugs, represents a rapidly evolving field wherein candidate compounds can be fine-tuned to access interactions with druggable biological targets. Moving in this direction, over the last few decades platinum family metals, e.g., ruthenium and palladium, have been largely proposed. Indeed, transition metals and molecular platforms where they originate are endowed with unique chemical and biological features based on, but not limited to, redox activity and coordination geometries, as well as ligand selection (including their inherent reactivity and bioactivity). Herein, current applications and progress in metal-based chemoth are reviewed. Converging on the recent literature, new attractive chemotherapeutics based on transition metals other than platinum—and their bioactivity and mechanisms of action—are examined and discussed. A special focus is committed to anticancer agents based on ruthenium, palladium, rhodium, and iridium, but also to gold derivatives, for which more experimental data are nowadays available. Next to platinum-based agents, ruthenium-based candidate drugs were the first to reach the stage of clinical evaluation in humans, opening new scenarios for the development of alternative chemotherapeutic options to treat cancer. Full article

Cancer is one of the leading causes of morbidity and mortality worldwide. Colorectal cancer (CRC) is the third most frequently diagnosed cancer in men and the second in women. Standard patterns of antitumor therapy, including cisplatin, are ineffective due to their lack of specificity for tumor cells, development of drug resistance, and severe side effects. For this reason, new methods and strategies for CRC treatment are urgently needed. Current research includes novel platinum (Pt)- and other metal-based drugs such as gold (Au), silver (Ag), iridium (Ir), or ruthenium (Ru). Au(III) compounds are promising drug candidates for CRC treatment due to their structural similarity to Pt(II). Their advantage is their relatively good solubility in water, but their disadvantage is an unsatisfactory stability under physiological conditions. Due to these limitations, work is still underway to improve the formula of Au(III) complexes by combining with various types of ligands capable of stabilizing the Au(III) cation and preventing its reduction under physiological conditions. This review summarizes the achievements in the field of stable Au(III) complexes with potential cytotoxic activity restricted to cancer cells. Moreover, it has been shown that not nucleic acids but various protein structures such as thioredoxin reductase (TrxR) mediate the antitumor effects of Au derivatives. The state of the art of the in vivo studies so far conducted is also described. Full article

Piano-stool iridium complexes based on the pentamethylcyclopentadienyl ligand (Cp*) have been intensively investigated as anticancer drug candidates and hold much promise in this setting. A systematic study aimed at outlining the effect of Cp* mono-derivatization on the antiproliferative activity is presented here. Thus, the dinuclear complexes [Ir(η⁵-C₅Me₄R)Cl(μ-Cl)]₂ (R = Me, 1a; R = H, 1b; R = Pr, 1c; R = 4-C₆H₄F, 1d; R = 4-C₆H₄OH, 1e), their 2-phenylpyridyl mononuclear derivatives [Ir(η⁵-C₅Me₄R)(k_N,k_CPhPy)Cl] (2a–d), and the dimethylsulfoxide complex [Ir{η⁵-C₅Me₄(4-C₆H₄OH)}Cl₂(κ_S-Me₂S=O)] (3) were synthesized, structurally characterized, and assessed for their cytotoxicity towards a panel of six human and rodent cancer cell lines (mouse melanoma, B16; rat glioma, C6; breast adenocarcinoma, MCF-7; colorectal carcinoma, SW620 and HCT116; ovarian carcinoma, A2780) and one primary, human fetal lung fibroblast cell line (MRC5). Complexes 2b (R = H) and 2d (4-C₆H₄F) emerged as the most active ones and were selected for further investigation. They did not affect the viability of primary mouse peritoneal cells, and their tumoricidal action arises from the combined influence on cellular proliferation, apoptosis and senescence. The latter is triggered by mitochondrial failure and production of reactive oxygen and nitrogen species. Full article

Targeting apoptosis is a principal strategy in the design of anticancer drugs. In recent years, non-platinum-based scaffolds have been exploited as viable candidates for the exploitation of anticancer agents with potentially lower toxicity than the widely used cisplatin analogues. This review highlights the latest advances in developing iridium(III) complexes as anticancer agents that act particularly via targeting apoptotic cell death in cancer cells. Full article