Determination of cisplatin and its hydrolytic metabolite in human serum by capillary electrophoresis techniques

Rapid spectrophotometric determination and extraction of platinum(IV) from pharmaceuticals assisted by 2-(2-(1-(thiophene-2-yl) ethylidene) hydrazinyl) benzoic acid (TEHBA)

It has been suggested that the chelating agent 2-(2-(1-thiophene-2-yl) ethylidene) hydrazinyl) benzoic acid (TEHBA) be utilized to extract, separate and measure platinum(IV) by UV-visible spectrophotometry at the microgram level. Following 5 min of heating the reaction mixture in a water bath, Pt(IV)-TEHBA complex formed. This complex was formed in the presence of potassium iodide solution with a molar absorption coefficient 1.9 × 103 dm3 mol-1 cm-1. At 420 nm, the substance exhibited the greatest absorption. As Beer's law described, the Pt(IV)-TEHBA complex for platinum(IV) has a beer's range of 10-50 μg cm-3. It was determined that the proportion ratio of the Pt(IV)-TEHBA complex was 1:1 after its extraction. Despite the investigation of interference from various ions, it was ascertained that the method exhibited selectivity exclusively towards platinum(IV). The trace amounts of platinum(IV) were extracted and quantified from synthetic mixtures representing alloys, binaries and ternary synthetic mixtures. The process of extracting platinum(IV) from pharmaceutical samples involves the implementation of a specific method. Moreover, the procedure exhibits a progressive segregation of palladium(II), platinum(IV) and nickel(II) while also boasting its ease of operation.

Environmental Hazard of Anticancer Drugs: State of the Art and Future Perspective for Marine Organisms

Pharmaceutical compounds represent a class of emerging contaminants present in the environment. Their intense (and increasing) use in human and veterinary medicine leads to their discharge, mainly via human excretion, into wastewater treatment plants where their removal is inefficient. A specific class of pharmaceuticals used to fight cancer, known as antineoplastic or anticancer drugs, has gained increased attention regarding their possible environmental hazard due to their pharmacological properties, which include the nonselective targeting of DNA replication mechanisms and cell division processes, potentially inducing cell apoptosis. To date, there is limited information concerning the effects of anticancer drugs and/or their metabolites in species inhabiting freshwater environments, let alone marine and estuarine compartments. In the present review, we aimed to assemble information regarding the impact that anticancer drugs have on biological traits of marine species, to identify gaps in the current environmental hazard assessment, and to make recommendations to promote an efficient environmental hazard assessment of anticancer drugs in the marine environment. Environ Toxicol Chem 2022;41:1793-1807. © 2022 SETAC.

A New Sensitive Method for Quantitative Determination of Cisplatin in Biological Samples by Kinetic Spectrophotometry

This study describes a kinetic spectrophotometric method for accurate, sensitive and rapid determination of cisplatin in biofluids. The developed method is based on the inhibitory effect of cisplatin on the oxidization of Janus Green by bromate in acidic media. The change in absorbance as the criteria of the oxidation reaction was followed spectrophotometrically. To obtain the highest rate of sensitivity, efficient reaction parameters were optimized. Under optimum experimental conditions, a calibration graph was obtained linearly over the range 10.0 - 5750.0 μg L^-1 and the limit of detection (3s_b/m) was 4.2 μg L^-1 of cisplatin. The interfering effect of diverse species was investigated. The developed method was used for the quantification of cisplatin in bio fluids of patients treated with cisplatin, spiked bio fluids and pharmaceutical samples and yielded satisfactory results.

Pharmacokinetics and tissue distribution in rats of a novel anticancer platinum compound LLC-1903

LLC-1903, a novel anticancer compound, was synthesized by optimizing the structure, which was derived from altering the leaving group of lobaplatin. It has an excellent in vitro anti-cancer activity, high water solubility, high stability in solution and low in vivo toxicity according to our former study.The plasma pharmacokinetics (PK) and tissue distribution of LLC-1903 and lobaplatin in rats were determined after intravenous administration of a single dose (0.06 mmol/kg body weight). Inductively coupled plasma mass spectrometry (ICP-MS) was used to measure the concentration of platinum (Pt) in plasma and tissue samples.Most PK parameters of the Pt in LLC-1903 showed a significant difference from those of lobaplatin. The plasma level of LLC-1903 is only half of that of lobaplatin (p < 0.01) which could be the direct result of faster drug clearance. The tissue distribution showed that both LLC-1903 and lobaplatin were mainly found in the liver and kidney, and less in other organs. At four time points (0.083, 0.5, 1 and 4 h) after administration, the tissue concentrations of LLC-1903 were almost always significantly higher than those of lobaplatin (p < 0.05 or p < 0.01).

A novel helper qPCR system for platinum detection via Pt-DNA coordination

A novel real-time polymerase chain reaction (qPCR) platform for the simple and robust detection of platinum is described for the first time. Compared with conventional qPCR, a helper template, which is related to the active template for performing qPCR, was introduced in our helper qPCR system. Several guanine (G) bases were introduced in the helper template to obtain a platinum-responsive on/off switch based on G-Pt-G coordination. Because of the helper template, a slight change in platinum concentration would significantly change the signal in the qPCR. This novel helper qPCR technique easily detects platinum with high sensitivity (1 ng/mL) and selectivity over other metal ions. Therefore, it will be a promising technique for the detection of platinum in biomedical and environmental samples.

Antineoplastic drugs and their analysis: a state of the art review

We provide an overview of the analytical methods available for the quantification of antineoplastic drugs in pharmaceutical formulations, biological and environmental samples.

A label-free colorimetric aptasensor for simple, sensitive and selective detection of Pt (II) based on platinum (II)-oligonucleotide coordination induced gold nanoparticles aggregation

Herein, a gold nanoparticles (AuNPs) based label-free colorimetric aptasensor for simple, sensitive and selective detection of Pt (II) was constructed for the first time. Four bases (G-G mismatch) mismatched streptavidin aptamer (MSAA) was used to protect AuNPs from salt-induced aggregation and recognize Pt (II) specifically. Only in the presence of Pt (II), coordination occurs between G-G bases and Pt (II), leading to the activation of streptavidin aptamer. Streptavidin coated magnetic beads (MBs) were used as separation agent to separate Pt (II)-coordinated MSAA. The residual less amount of MSAA could not efficiently protect AuNPs anymore and aggregation of AuNPs will produce a colorimetric product. With the addition of Pt (II), a pale purple-to-blue color variation could be observed by the naked eye. A detection limit of 150nM and a linear range from 0.6μM to 12.5μM for Pt (II) could be achieved without any amplification.

Platinum(II)-Oligonucleotide Coordination Based Aptasensor for Simple and Selective Detection of Platinum Compounds

Wide use of platinum-based chemotherapeutic regimens for the treatment for carcinoma calls for a simple and selective detection of platinum compound in biological samples. On the basis of the platinum(II)-base pair coordination, a novel type of aptameric platform for platinum detection has been introduced. This chemiluminescence (CL) aptasensor consists of a designed streptavidin (SA) aptamer sequence in which several base pairs were replaced by G-G mismatches. Only in the presence of platinum, coordination occurs between the platinum and G-G base pairs as opposed to the hydrogen-bonded G-C base pairs, which leads to SA aptamer sequence activation, resulting in their binding to SA coated magnetic beads. These Pt-DNA coordination events were monitored by a simple and direct luminol-peroxide CL reaction through horseradish peroxidase (HRP) catalysis with a strong chemiluminescence emission. The validated ranges of quantification were 0.12-240 μM with a limit of detection of 60 nM and selectivity over other metal ions. This assay was also successfully used in urine sample determination. It will be a promising candidate for the detection of platinum in biomedical and environmental samples.

Cisplatin-Induced Ototoxicity: Effects, Mechanisms and Protection Strategies

Cisplatin is a highly effective chemotherapeutic agent that is widely used to treat solid organ malignancies. However, serious side effects have been associated with its use, such as bilateral, progressive, irreversible, dose-dependent neurosensory hearing loss. Current evidence indicates that cisplatin triggers the production of reactive oxygen species in target tissues in the inner ear. A variety of agents that protect against cisplatin-induced ototoxicity have been successfully tested in cell culture and animal models. However, many of them interfere with the therapeutic effect of cisplatin, and therefore are not suitable for systemic administration in clinical practice. Consequently, local administration strategies, namely intratympanic administration, have been developed to achieve otoprotection, without reducing the antitumoral effect of cisplatin. While a considerable amount of pre-clinical information is available, clinical data on treatments to prevent cisplatin ototoxicity are only just beginning to appear. This review summarizes clinical and experimental studies of cisplatin ototoxicity, and focuses on understanding its toxicity mechanisms, clinical repercussions and prevention strategies.

A novel method for speciation of Pt in human serum incubated with cisplatin, oxaliplatin and carboplatin by conjoint liquid chromatography on monolithic disks with UV and ICP-MS detection

Conjoint liquid chromatography (CLC) on monolithic convective interaction media (CIM) disks coupled on-line to UV and inductively coupled plasma mass spectrometry (ICP-MS) detectors was used for the first time in speciation analysis of Pt in human serum spiked with Pt-based chemotherapeutics. CIM Protein G and CIM DEAE disks were assembled together in a single housing forming a CLC monolithic column. Such a set-up allows rapid two-dimensional separation by affinity and ion-exchange (IE) modes to be carried out in a single chromatographic run. By applying isocratic elution with Tris-HCl-NaHCO3 buffer (pH 7.4) in the first minute, followed by gradient elution with 1 mol L(-1) NH4Cl (pH 7.4) in the next 9 min, immunoglobulins (IgG) were retained by the Protein G disk enabling subsequent separation of unbound Pt from Pt bound to transferrin (Tf) and albumin (HSA) on the CIM DEAE disk. Further elution with acetic acid (AcOH) in the next 3 min allowed separation of Pt associated with IgG. Separated Pt species were quantified by post-column isotope dilution-ICP-MS. Pt recovery on the CLC column was close to 100%. In comparison to commonly applied procedures that involve separation of protein peaks by size-exclusion chromatography (SEC) followed by IE separation of metal-based chemotherapeutic fractions bound to serum proteins, the CLC method developed is much faster and simpler. Its sensitivity (LOQs adequate for quantification of all separated Pt species, lower than 2.4 ng Pt mL(-1)), good selectivity and method repeatability (RSD±3%) enabled investigation of the kinetics of interaction of Pt-based chemotherapeutics with serum proteins and the distribution of Pt species in spiked human serum. Pt species present in spiked serum were bound preferentially to HSA. The proportion of Pt associated with IgG and Tf was lower than 13%. Cisplatin and especially oxaliplatin react rapidly with serum proteins, while carboplatin much less. The method developed may be reliably applied in preclinical and clinical studies of the kinetics of the interaction and distribution of different metallodrugs with proteins in blood serum.

Analysis of anticancer drugs: a review

In the last decades, the number of patients receiving chemotherapy has considerably increased. Given the toxicity of cytotoxic agents to humans (not only for patients but also for healthcare professionals), the development of reliable analytical methods to analyse these compounds became necessary. From the discovery of new substances to patient administration, all pharmaceutical fields are concerned with the analysis of cytotoxic drugs. In this review, the use of methods to analyse cytotoxic agents in various matrices, such as pharmaceutical formulations and biological and environmental samples, is discussed. Thus, an overview of reported analytical methods for the determination of the most commonly used anticancer drugs is given.

Microflow injection chemiluminescence system with spiral microchannel for the determination of cisplatin in human serum

A new microflow injection chemiluminescence (μFI-CL) system was described for the determination of cisplatin in human serum. By using the microchip with double spiral channel configuration, the sensitivity was greatly enhanced due to more efficient mixing of the analyte and reagent solutions. Experimental results revealed that common ions in human serum, such as Mn(2+), Co(2+), Fe(3+), Cu(2+), Zn(2+), Ni(2+), Na(+), K(+), Ca(2+), Cl(-), NO(3)(-), Ac(-), CO(3)(2-), PO(4)(3-), SO(4)(2-) did not cause interference with the detection of Pt(II) by using 1,10-phenanthroline as the masking agent. Under the optimized conditions, a linear calibration curve (R(2)=0.998) over the range 2.0 × 10(-8) to 2.0 × 10(-6) mol L(-1) was obtained with the detection limit of 1.24 × 10(-9) mol L(-1). The relative standard deviation was found to be 3.46% (n=12) for 2.0 × 10(-7) mol L(-1). The sample consumption was only 2 μL with the sample throughput of 72 h(-1). It had been used for trace platinum determination in cisplatin injection and human serum samples after the dosage of cisplatin. The recovery varied from 97.6 to 103.9%. The results proved that the proposed μFI-CL system had the advantages of high sensitivity and precision, low sample and reagents consumption, and high analytical throughput.

Platinum speciation used for elucidating activation or inhibition of Pt-containing anti-cancer drugs

This article reviews approaches on platinum speciation with respect to Pt drugs in anti-cancer therapies. The paper starts with the introduction of available platinum-based drugs and describes their assumed principle of action. It is now generally accepted that these Pt complexes exhibit their therapeutic action by coordination to DNA which leads to bending of the DNA structure and to an inhibition of the DNA polymerase progression. But dose-limiting side effects, including nephrotoxicity as well as resistance to some of these Pt compounds, are still a major problem. Platinum speciation moved increasingly into the focus of interest when it became clear that (1) the active drugs were the hydrolyzation products rather than the originally administered ones and (2) that the parallel formation of inactive Pt-protein complexes, which additionally reduce the efficacy of Pt anti-tumor agents, compete with the formation of the cytotoxic Pt-DNA lesions. Speciation analysis methods were employed based on chromatography or capillary electrophoresis respectively, each coupled to inductively coupled plasma (ICP)-mass spectrometry (MS) or electrospray ionization (ESI)-MS. The paper describes these Pt-speciation investigations, which started with exploring hydrolyzation kinetics in aqueous solutions. These experiments were followed by the speciation investigations in model solutions containing proteins or other sulphur-containing ligands, which could also be responsible for deactivation of the Pt agent in vivo. The experiments improved the understanding of the metabolite form, by which the metal complex enters the tumor cells, and whether and how this metabolized complex is already inactivated at this time. As an example, reaction kinetics of cisplatin (cis-[diamminedichloroplatinum(II)]) with albumin, transferrin, myoglobin, ubiquitin, and metallothionein were investigated and reaction products were speciated. Finally, Pt-speciation in serum of medicated cancer patients was conducted by several research groups, which are outlined in the Section "Investigations in serum". The section "Investigations in urine of cancer treated patients" deals with speciation experiments on the Pt-metabolites excreted by the organism. By these means an assessment of the in vivo metabolism of Pt-drugs may be possible. Finally, the development of new anti-cancer metallodrugs needs the respective analytical techniques reported in the last section of the paper.

Cisplatin ototoxicity and protection: clinical and experimental studies

Cisplatin is a chemotherapeutic agent that is widely used to treat a variety of malignant tumors. Serious dose-limiting side effects like ototoxicity, nephrotoxicity and neurotoxicity occur with the use of this agent. This review summarizes recent important clinical and experimental investigations of cisplatin ototoxicity. It also discusses the utility of protective agents employed in patients and in experimental animals. The future strategies for limiting cisplatin ototoxicity will need to avoid interference with the therapeutic effect of cisplatin in order to enhance the quality of life of patients receiving this important anti-tumor agent.

Analytical methodologies for the determination of cisplatin

cis-Diamminedichloroplatinum(II) (cisplatin) is a important chemotherapeutic drug for cancer treatment since 1978. Unfortunately, because of the severe side-effects like nephrotoxicity, ototoxicity, etc., they are administered in small doses at low concentration establishing the maximum limit dosage to 100 mg/m(2) (21 days). A variety of analytical methods have been proposed for the determination of cisplatin in biological fluids and tissues that permit the accurate determination at or below the part per billion level in the native sample. The purpose of the current review is to provide a systematic survey of the latest analytical techniques for the determination of cisplatin in biological samples.

Recent trends in CE of inorganic ions: From individual to multiple elemental species analysis

The major methodological developments in CE related to inorganic analysis are overviewed. This is an update to a previous review article by the author (Timerbaev, A. R., Electrophoresis 2004, 25, 4008-4031) and it covers the review work and innovative research papers published between January 2004 and the first part of 2006. As was underlined in that review, a growing interest of analytical community in providing elemental speciation information found a sound response of the CE method developers. Presently, almost every second research paper in the field of interest deals with element species analysis, the use of inductively coupled plasma MS detection and biochemical applications being the topics of utmost research efforts. On the other hand, advances in general methodology traditionally centered on a CE system modernization for improvements in sensitivity and separation selectivity have attracted less attention over the review period. While there is no indication that inorganic ion applications would surpass by the developmental rate the more matured analysis of organic analytes, CE can now be seen as an analytical technique to be before long customary in a number of inorganic analysis arenas.

CE in anticancer metallodrug research – an update

With the current demographic development and the knowledge that the probability to be diagnosed with cancer increases with age, the search for new treatment options in cancer chemotherapy is of utmost importance for the society. Capillary electrophoretic methods have been applied in the last few years for studying the properties of metal-based drugs and drug candidates. Especially, the elucidation of the mode of action of such compounds could contribute significantly to design new drugs for overcoming the threat of cancer. This review article highlights the developments in metallodrug research applying CE during the last 4 years and follows a review from 2003 (Hartinger, C. G., Timerbaev, A. R., Keppler, B. K., Electrophoresis 2003, 24, 2023-2037). Most importantly the broadening of application areas of CE must be noted: especially the binding studies of metal complexes toward proteins (including the determination of association and rate constants), following redox reactions of metal complexes and their influence on the reactivity toward biotargets, etc. are important development areas of the last few years. In parallel with these new applications goes the usage of new or modified separation methods including microemulsion EKC or ACE, or the advantageous use of equipping the CE system with mass spectrometric detectors such as inductively coupled plasma (ICP) or ESI mass spectrometers (MS) for determining the degree of metallation of a protein or characterizing the adducts. Finally, upcoming requirements for expanding the method's application area are discussed including studies on new targets in the cell, analyzing real-world samples, methodological development, and contributions to improve the design of new anticancer agents.

Structure−Activity Relationships for NAMI-A-type Complexes (HL)[trans-RuCl4L(S-dmso)ruthenate(III)] (L = Imidazole, Indazole, 1,2,4-Triazole, 4-Amino-1,2,4-triazole, and 1-Methyl-1,2,4-triazole): Aquation, Redox Properties, Protein Binding, and Antiproliferative Activity

Imidazolium [trans-tetrachloro(1H-imidazole)(S-dimethylsulfoxide)ruthenate(III)] (NAMI-A) and indazolium [trans-tetrachlorobis(1H-indazole)ruthenate(III)] (KP1019) are the most promising ruthenium complexes for anticancer chemotherapy. In this study, the azole ligand of NAMI-A was systematically varied (from imidazole of NAMI-A to indazole, 1,2,4-triazole, 4-amino-1,2,4-triazole, and 1-methyl-1,2,4-triazole), and the respective complexes were evaluated with regard to the rate of aquation and protein binding, redox potentials, and cytotoxicity by means of capillary zone electrophoresis, electrospray ionization mass spectrometry, cyclic voltammetry, and colorimetric microculture assays. Stability studies demonstrated low stability of the complexes at pH 7.4 and 37 degrees C and a high reactivity toward proteins (binding rate constants in the ranges of 0.02-0.34 and 0.01-0.26 min-1 for albumin and transferrin, respectively). The redox potentials (between 0.25 and 0.35 V) were found to be biologically accessible for activation of the complexes in the tumor, and the indazole-containing compound shows the highest antiproliferative activity in vitro.

Application of micellar and microemulsion electrokinetic chromatography for characterization of gallium(III) complexes of pharmaceutical significance

CE with conventional UV detection has recently been shown as a highly effective means to assaying cytotoxic gallium(III)-based compounds with regard to desirable drug-like properties such as the stability and binding to serum proteins. In this extension of that work, different CE techniques are used to further characterize a given set of gallium coordination compounds with established antiproliferating efficacy. Using free-zone CE mode, the electrophoretic profiles of complexes are recorded in order to assess their actual charge state under physiological buffer conditions. Micellar and microemulsion electrokinetic chromatographic techniques are tested as tools for the rapid estimation of the n-octanol-water partition coefficient (log P) that provides a rationale estimate of a drug's ability to cross biological membranes. A range of electrolyte buffer systems with varying (both in the nature and concentration) organic modifiers are examined to evaluate their effect on the relationship between experimental or calculated log P and the retention factors of compounds (log k'). Both methods were found to be better applicable for neutral than for cationic Ga complexes, the microemulsion mode demonstrating superior lipophilicity estimations as well as statistically meaningful log P versus log k' correlations when all the complexes were included in one regression set.

Contemporary sample stacking in CE: A sophisticated tool based on simple principles

Sample stacking is a general term for methods in CE which are used for on-line concentration of diluted analytes. During the stacking process, analytes present at low concentrations in a long injected sample zone are concentrated into a short zone (stack). The stacked analytes are then separated and individual zones are detected. Thus stacking provides better separation efficiency and detection sensitivity. Many papers have been published on stacking till now, various procedures have been described, and, many names have been proposed for stacking procedures utilizing the same principles. This contribution brings an easy and unified view on stacking, describes the basic principles utilized, makes a list of recognized operational principles and brings an overview of principal current procedures. Further, it surveys selected recent practical applications ordered according to their operational principles and includes the terms, nicknames, and acronyms used for these actual stacking procedures. This contribution may help both newcomers and experts in the field of CE to orient themselves in the already quite complex topic of sample stacking.

Capillary isotachophoresis from the student point of view – images and the reality

A review of some fundamental aspects of ITP from the student point of view, imaginations of some basic facts and laws, use of ITP, and the recent trends are presented. The results of theoretical computations of ITP separation processes are added for comparison of imaginations with the exact mathematical description.

Preclinical characterization of anticancer gallium(III) complexes: Solubility, stability, lipophilicity and binding to serum proteins

The discovery and development of gallium(III) complexes capable of inhibiting tumor growth is an emerging area of anticancer drug research. A range of novel gallium coordination compounds with established cytotoxic efficacy have been characterized in terms of desirable chemical and biochemical properties and compared with tris(8-quinolinolato)gallium(III) (KP46), a lead anticancer gallium-based candidate that successfully finished phase I clinical trials (under the name FFC11), showing activity against renal cell cancer. In view of probable oral administration, drug-like parameters, such as solubility in water, saline and 0.5% dimethyl sulfoxide, stability against hydrolysis, measured as the rate constant of hydrolytic degradation in water or physiological buffer using a capillary zone electrophoresis (CZE) assay, and the octanol-water partition coefficient (logP) providing a rational estimate of a drug's lipophilicity, have been evaluated and compared. The differences in bioavailability characteristics between different complexes were discussed within the formalism of structure-activity relationships. The reactivity toward major serum transport proteins, albumin and transferrin, was also assayed in order to elucidate the drug's distribution pathway after intestinal absorption. According to the values of apparent binding rate constants determined by CZE, both KP46 and bis(2-acetylpyridine-4,4-dimethyl-3-thiosemicarbazonato-N,N,S)gallium(III) tetrachlorogallate(III) (KP1089) bind to transferrin faster than to albumin. This implies that transferrin would rather mediate the accumulation of gallium antineoplastic agents in solid tumors. A tendency of being faster converted into the protein-bound form found for KP1089 (due possibly to non-covalent binding) seems complementary to its greater in vitro antiproliferative activity.