Flow injection chemiluminescent determination of amiodarone in pharmaceutical preparations using photogenerated tris(2,2'-bipyridyl)ruthenium(III)

A flow injection configuration was developed and evaluated for the chemiluminescent determination of amiodarone. The method is based on the reaction of the drug with tris(2,2'-bipyridyl)ruthenium(III), which was generated through the on-line photo-oxidation of tris(2,2'-bipyridyl)ruthenium(II) with peroxydisulfate. Under the optimum experimental conditions, a linear calibration graph was obtained over the range 3.0-60.0 microg ml(-1) with a detection limit of 0.28 microg ml(-1). The proposed method allows 120 injections h(-1) with excellent repeatability and precision (R.S.D. less than 0.5% and 2.8%, respectively) and a reagent consumption of only 0.37 micromol (0.27 mg) of Ru(bpy)(3)Cl(2) x 6H(2)O per determination. The method was successfully applied to the determination of amiodarone in commercial pharmaceutical formulations.     

Synthesis of redox derivatives of lysine and related peptides containing phenothiazine or tris(2,2′-bipyridine)ruthenium(II)

Boc-l -Lysine derivatives and lysine-containing peptides bearing the electron donor 10H-phenothiazine (PTZ) or the redox chromophore tris(2,2′-bipyridine)ruthenium(II) dication ([Rub₃,]^2H, where b is 2,2-bipyridine) have been synthesized and characterized. SeO₂ oxidation (53% yield) of 4,4′-dimethyl-2,2′-bipyridine, Ag_2:O oxidation (85% yield) of the monoaldehyde, complexation (96% yield) of 4′-methyl-2,2′-bipyridine-4-carboxylic acid (m-OH) with Rub₂Cl_2:. activation (81% yield) of the acid [Rub₂m-OH]²⁺ (PF₆^?)₂, and condensation (83% yield) of the succinimido ester [Rub₂m-OSu]²⁺ (PF₆^?)₂ with Boc-Lys furnished the protected redox-chromophore module [Boc-Lys(Rub₂m)-OH]²⁺(PF₆^?)₂ in 29% overall yield over five steps. The first two steps constitute the first practical synthesis of the monocarboxylic acid m-OH (45% overall yield). Also prepared were m-OSu, Boc-Lys(m)-OH, Boc-Lys(m)-OCH₃, and [Rub₂m-NHCH₃]²⁺ (PF₆^?)_2:. Activation (91% yield) of 3-(10H-phenothiazine-10)propanoic acid (PTZpn-OH) and condensation (92% yield) of the succinimido ester PTZpn-OSu with Boc-Lys furnished the protected electron-donor module Boc-Lys(PTZpn)-OH (84% overall yield). The latter was used in solid-phase syntheses of two redox tripeptides. CH₃CO-Ala-Lys(PTZpn)-Ala-OH and [Rub₂m-Ala-Lys(PTZpn)-Ala-OH]² (PF₆^?)₂. The electrochemical properties of these redox amino acids and peptides were similar to those of PTZpn-OH, [Rub₂ m-OH]2⁺(PF₆)₂. or [Rub₂ m-NHCH₃]²⁺ (PF₆^?)₂. Lys(PTZpn). [Lys(Rub₂m)]²⁺ (PF₆)_2:. and other redox modules may be useful for engineering light-harvesting proteins, photovoltaic cells, and other molecular electronic devices.     

Antitumour properties of dimethylsulphoxide ruthenium (II) complexes in the Lewis lung carcinoma system

The antitumour effects of some ruthenium (II) complexes were tested in mice bearing the solid metastasizing tumour, Lewis lung carcinoma. The toxicity of trans-RuCl2 (DMSO)4 is 10-fold higher than that of its cis-isomer. Qualitatively the antitumour activity of these two complexes is comparable, although trans-isomer is more potent. Both exhibit only marginal effects on primary tumour growth while significantly lowering lung metastasis formation. The effects of trans-RuCl2 (DMSO)4 on primary tumour depend on the inoculum size, being more pronounced with low tumour inocula; significant antitumour effects can be achieved also by replacing Cl with I in the molecule. trans-RuCl2(DMSO)4 markedly reduces the number of lung metastases and particularly their volume; the reduction is comparable to that obtained with equitoxic treatments of cisplatin. Treatment with trans-RuCl2(DMSO)4 for 10 consecutive days, after surgical amputation of primary tumour, significantly prolongs the survival time of the treated mice; cisplatin, at equitoxic doses, is less effective. These data show that dimethylsulphoxide ruthenium(II) complexes possess a significant antitumour and antimetastatic activity in the Lewis lung system, also exhibiting an interesting therapeutic potential when combined with surgical amputation of the primary tumour.     

Flow-injection biamperometric direct determination of calcium dobesilate in irreversible couple system

A flow-injection biamperometric method for direct determination of calcium dobesilate had been proposed based on biamperometric detection for irreversible couple. The detection was realized by coupling the oxidation of dobesilate at one platinum wire electrode with the reduction of MnO(4)(-) at another one with the applied potential difference of 0 V between two platinum wire electrodes. Dobesilate was determined in the range of 4.0 x 10(-6) to 1.0 x 10(-4) M with the detection limit of 8.0 x 10(-7) M (S/N=3). The relative standard derivation of 1.7% was obtained for 24 successive determinations of 4.0 x 10(-5) M dobesilate. The proposed method had been shown to be sensitive, simple and rapid.     

Chemiluminescence detection of MDMA in street drug samples using tris(2,2′‐bipyridine)ruthenium(III)

Tris(2,2′‐bipyridine)ruthenium(II) chemiluminescence was investigated for the detection of 3,4‐methylenedioxymethamphetamine (MDMA) and several related compounds in street drug samples. Optimization using flow injection analysis showed that the selectivity of the reagent can be targeted towards the detection of secondary amines by altering the pH of the reaction environment. The greater selectivity of this mode of detection, compared to UV‐absorbance, reduces the probability of false positive results from interfering compounds. The detection limit for MDMA under these conditions was 0.48 μM. A HPLC method incorporating post‐column tris(2,2′‐bipyridine)ruthenium(II) chemiluminescence detection was applied to the determination of MDMA in five street drug samples. The results obtained were in good agreement with quantification performed using traditional UV‐absorbance detection, which demonstrates the viability of this method for confirmatory analysis of drug samples. This is the first report of tris(2,2′‐bipyridine)ruthenium(II) chemiluminescence for the detection of MDMA and related amphetamine derivatives. Copyright © 2015 John Wiley & Sons, Ltd.     

Flow-injection determination of isoniazid using sodium dichloroisocyanurate- and trichloroisocyanuric acid-luminol chemiluminescence systems

A chemiluminescent (CL) method for the determination of isoniazid is described. The method is based on the CL generated during the oxidation of luminol by sodium dichloroisocyanurate (SDCC) and trichloroisocyanuric acid (TCCA) in alkaline medium. It was found that isoniazid greatly enhances this CL intensity when present in the luminol solution. Based on this observation, a new flow-injection CL method for the determination of isoniazid has been proposed in this paper. The detection limits were 2 and 3 ng ml(-1) isoniazid for the SDCC-luminol and TCCA-luminol CL systems, respectively. The relative CL intensity was linear with the isoniazid concentration in the range of 4-100 and 100-200 ng ml(-1) for the SDCC-luminol CL system, and 6-200 and 200-1000 ng ml(-1) for the TCCA-luminol CL system. The results obtained for the assay of pharmaceutical preparations compared well with those obtained by the official methods and demonstrated good accuracy and precision.     

Organometallic ruthenium(II) arene compounds with antiangiogenic activity

The antimetastatic ruthenium(II) compounds [Ru(η(6)-p-cymene)Cl(2)(PTA)] (PTA = 1,3,5-triaza-7-phosphaadamantane) (RAPTA-C) and [Ru(η(6)-toluene)Cl(2)(PTA)] (RAPTA-T), as well as their analogues [Ru(η(6)-p-cymene)Cl(2)(DAPTA)] (DAPTA = (3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane)) (DAPTA-C) and [Ru(η(6)-toluene)Cl(2)(DAPTA)] (DAPTA-T), respectively, were tested in in vitro bioassays for endothelial cell function. All compounds showed low toxicity profiles and similar dose-dependent antiproliferative effects in endothelial cells at ≥100 μg/mL (～200 μM). EC migration, measured 6 h after drug exposure, was also efficiently inhibited (ED(50) of ～300 μg/mL, ～500 μM, for all compounds). Since no cytostatic effect was noted, the inhibition of proliferation was considered mainly to consist of antiangiogenic activity. RAPTA-T and DAPTA-C were also tested in vivo in the chicken chorioallantoic membrane (CAM) assay and found to inhibit CAM development. Importantly, effective prevention of revascularization of the CAM after vaso-occlusive photodynamic therapy was observed. The reported ruthenium complexes show promising antimetastatic activity involving inhibition of angiogenesis and therefore are attractive agents for development of anticancer therapies based on combination of chemo- and angiostatic treatments.     

Green conversion of citral and citronellal using tris(bipyridine)ruthenium(II)-supported saponite catalyst under microwave irradiation

Citral and citronellal are important chemicals in the pharmaceutical and chemical industries, since they can be converted into other more valuable chemicals that are needed in many pathways. From the perspective of green catalysis, the present investigation examines the preparation of a recyclable heterogeneous catalyst of ruthenium-supported saponite clay for microwave assisted catalytic hydrogen transfer. Catalysts were prepared by supporting ruthenium bipyridine cations within saponite interlayers at various ruthenium contents, and the catalysts were then characterized by x-ray diffraction (XRD), gas sorption measurements, and scanning electron microscopy-energy dispersive x-ray spectrometry (SEMEDX) analyses. The catalytic activity was determined using microwave-assisted conversion of citral and citronellal. The prepared catalysts exhibited significant activity in the microwave-assisted catalytic hydrogen transfer of citral and citronellal. The catalytic activity was related to the content of the supported ruthenium in the catalysts, which also contributed to the increased specific surface area and external surface area of the materials.     

New cytotoxic and water-soluble bis(2-phenylazopyridine)ruthenium(II) complexes

New water-soluble bis(2-phenylazopyridine)ruthenium(II) complexes, all derivatives of the highly cytotoxic alpha-[Ru(azpy)(2)Cl(2)] (alpha denoting the coordinating pairs Cl, N(py), and N(azo) as cis, trans, cis, respectively) have been developed. The compounds 1,1-cyclobutanedicarboxylatobis(2-phenylazopyridine)ruthenium(II), alpha-[Ru(azpy)(2)(cbdca-O,O')] (1), oxalatobis(2-phenylazopyridine)ruthenium(II), alpha-[Ru(azpy)(2)(ox)] (2), and malonatobis(2-phenylazopyridine)ruthenium(II), alpha-[Ru(azpy)(2)(mal)] (3), have been synthesized and fully characterized. X-ray analyses of 1 and 2 are reported, and compound 1 is the first example in which the cbdca ligand is coordinated to a ruthenium center. The cytotoxicity of this series of water-soluble bis(2-phenylazopyridine) complexes has been determined in A2780 human ovarian carcinoma and A2780cisR, the corresponding cisplatin-resistant cell line. For comparison reasons, the cytotoxicity of the complexes alpha-[Ru(azpy)(2)Cl(2)], alpha-[Ru(azpy)(2)(NO(3))(2)], beta-[Ru(azpy)(2)Cl(2)] (beta indicating the coordinating pairs Cl, N(py), and N(azo) as cis, cis, cis, respectively), and beta-[Ru(azpy)(2)(NO(3))(2)] have been determined in this cell line. All the bis(2-phenylazopyridine)ruthenium(II) compounds display a promising cytotoxicity in the A2780 cell line (IC(50) = 0.9-10 microM), with an activity comparable to that of cisplatin and even higher than the activity of carboplatin. Interestingly, the IC(50) values of this series of ruthenium compounds (except the beta isomeric compounds) are similar in the cisplatin-resistant A2780cisR cell line compared to the normal cell line A2780, suggesting that the activity of these compounds might not be influenced by the multifactorial resistance mechanism that affect platinum anticancer agents.     

Inhibition of cancer cell growth by ruthenium(II) arene complexes

Inhibition of the growth of the human ovarian cancer cell line A2780 by organometallic ruthenium(II) complexes of the type [(eta(6)-arene)Ru(X)(Y)(Z)], where arene is benzene or substituted benzene, X, Y, and Z are halide, acetonitrile, or isonicotinamide, or X,Y is ethylenediamine (en) or N-ethylethylenediamine, has been investigated. The X-ray crystal structures of the complexes [(eta(6)-p-cymene)Ru(en)Cl]PF(6) (5), [(eta(6)-p-cymene)RuCl(2)(isonicotinamide)] (7), and [(eta(6)-biphenyl)Ru(en)Cl]PF(6) (9) are reported. They have "piano stool" geometries with eta(6) coordination of the arene ligand. Complexes with X,Y as a chelated en ligand and Z as a monofunctional leaving group had the highest activity. Complexes 5, 6 (the iodo analogue of 5), 9, and 10 (ethylethylenediamine analogue of 9) were as active as carboplatin. Hydrolysis of the reactive Ru-Cl bond in complex 5 was detected by HPLC but was suppressed by the addition of chloride ions. Complex 5 binds strongly and selectively to G bases on DNA oligonucleotides to form monofunctional adducts. No inhibition of topoisomerase I or II by complexes 5, 6, or 9 was detected. These chelated Ru(II) arene complexes have potential as novel metal-based anticancer agents with a mechanism of action different from that of the Ru(III) complex currently on clinical trial.     

Simultaneous determination of zinc(II), manganese(II) and iron(II) in pharmaceutical preparations

The applicability of derivative spectrophotometry for simultaneous determination of zinc(II), manganese(II) and iron(II) in the form of PAR complexes was presented and discussed. Beer's law was obeyed in range 0.025-13 ppm for zinc 1-20, for manganese and 0.025-0.2 for iron ion. The elaborated method was applied successfully for determination of mentioned ions in pharmaceutical preparation without previous separation. The error of the determination did not exceed +/-3%.     

Flow-injection chemiluminescence determination of phentolamine based on its enhancing effect on the luminol-potassium ferricyanide system

It was found that the light emission produced by the oxidation of luminol by potassium ferricyanide in the basic medium was enhanced by phentolamine, a drug recently used to treatment of male and female sexual dysfunction. The optimum conditions for this chemiluminescent reaction were studied in detail by a flow-injection system. A new, simple and rapid method has been developed under the optimum conditions for determination of phentolamine. This method has the advantages of high sensitivity, good reproducibility and low detection limit. On the basis of investigation of chemiluminescent, fluorescent and UV spectra of phentolamine in basic solution containing potassium ferricyanide and luminol, a possible mechanism of this reaction was proposed. In the optimum conditions, CL intensities are proportional to concentrations of the phentolamine in the 0.01-1 microg/mL range. The limit of detection is 3.0 ng/mL for phentolamine. The method has been applied to the determination of phentolamine in the commercial preparations, synthetic samples and biological fluids with satisfactory results.     

Direct determination of Pb(II) and Cd(II) ions as impurities in some homeopathic drugs by using stripping voltammetry

The conditions for identification and quantilication of Pb(II) and Cd(II) ions as impurities in homeopathic preparations by stripping voltammetry were established. The tests proved that the method was of high selectivity. The detection limits were 0.78 ng/mL and 1.56 ng/mL for Pb(II) and Cd(II) ions, respectively. The method was characterised by: repeatability of measurements, a wide range of linearity and satisfactory percent recovery. The Pb(II) and Cd(II) ions were detected in examined drugs as impurities at concentrations of 1.23 ? 9.5 ng/mL and 1.66 ? 3.7 ng/mL for Pb(II) and Cd(II), accordingly.     

pK(a) determination of angiotensin II receptor antagonists (ARA II) by spectrofluorimetry

The acid-base equilibrium constants of a new family of antihypertensive drugs, the angiotensin II receptor antagonists (ARA II), Losartan, Irbesartan, Valsartan, Candesartan cilexetil, its metabolite Candesartan M1 and Telmisartan were determined by spectrofluorimetry. Relative fluorescent intensity (I(F,rel))-pH data were treated by graphical (derivatives and curve-fitting) and numerical methods (LETAGROP SPEFO). The resultant pK(a) values at an ionic strength of 0.5 M were (3.15+/-0.07) for Losartan, (4.70+/-0.06) for Irbesartan, (4.90+/-0.09) for Valsartan, (6.0+/-0.1) for Candesartan cilexetil, (3.9+/-0.1) for Candesartan M1, and (4.45+/-0.09) for Telmisartan.     

Flow-injection amperometric determination of dopamine in pharmaceuticals using a polyphenol oxidase biosensor obtained from soursop pulp

The amperometric determination of dopamine (Do) in pharmaceuticals formulations by flow injection analysis (FIA) is proposed. An enzymatically modified carbon paste electrode constituted by 25% (w/w) of polyphenol oxidase obtained from Annona muricata L. tissue, 30% (w/w) of graphite, 30% (w/w) of silicone and 15% (w/w) of 7,7,8,8 tetracyanoquinodimethane (TCNQ), was used as flow-through detector. The flow amperometric detection was carried out at a potential of 0.10 V (vs. Ag/AgCl) when an injected sample volume of 250 μl was inserted on a 0.3 M phosphate buffer carrier solution (pH 7.8) flowing at 2.5 ml/min. The developed biosensor showed good stability and reproducibility, enabling up to 500 determinations in 60 days, without considerable loss of enzymatic activity. The FIA system presented a linear response to Do concentrations in the interval from 2×10⁻² to 2×10⁻⁴ M, with relative standard deviations lower than 1.5%. The kinetic parameter K_M for the soluble and immobilized enzyme was 1.45×10⁻² and 1.91×10⁻² M, respectively. In the analyses of different commercially pharmaceutical formulations a relative deviation lower than about 3.4% was obtained.     

全自动免疫化学发光分析法测定人血清中甲钴胺浓度及其药动学研究

目的:通过IMMULITE 2000全自动免疫化学发光分析仪(Automated immunoassay chemiluminescent system,AICS)测定人血清中甲钴胺的浓度,并研究其药动学.方法:在二硫代苏糖醇和氰化钾存在的条件下,含甲钴胺的血清样品经100℃水煮后,用IMMULITE 2000分析仪进行自动分析测定.并检测3例健康志愿者单剂量口服1.5 mg甲钴胺片的不同时间的血清药物浓度,用3P97药动学程序计算药动学参数.结果:线性范围为10～1 200 pg·mL-1,低、中、高3种不同浓度的回收率分别为105.7%,99.5%和101.6%,RSD分别为10.7%,3.6%和4.1%;日内精密度分别为10.3%,5.6%和2.4%;日间精密度分别为12.6%,4.3%和2.7%.甲钴胺的主要药动学参数为Tmax为(2.67±0.58)h,Cmax为(271±76.45)pg·mL-1,AUC(0～72h)为(5 722,33±1 630.04)pg·h·mL-1.结论:本方法准确、可靠、简便,可用于人血清中甲钴胺的浓度测定及药动学研究.     

Acute toxicity evaluation of a thiazolo arene ruthenium (II) complex in rats

Recently, a series of thiazolo arene ruthenium complexes were found to be highly cytotoxic in vitro, on both cisplatin-sensitive and cisplatin-resistant ovarian cancer cells. The most active compound of the series, [(η⁶-p-cymene)Ru(L)Cl]Cl (L = 1-(2-(2-(3-chlorobenzylidene)hydrazinyl)-4-methylthiazol-5-yl)ethanone), was selected for an in vivo study in order to assess its safety profile.The ruthenium complex was administered to female Crl:WI rats orally, by gastric intubation and intraperitoneal injection. The hematological parameters and the histopathological changes in liver, kidneys, spleen and brain were investigated after a 14-days treatment. The substance was very well tolerated orally, with a LD₅₀ value of over 2000 mg/kg body weight. Symptoms were observed only in the first day after intraperitoneal administration of the highest dose, with a LD₅₀ value between 300 and 2000 mg/kg bw. The hematological profile was not modified at any of the tested doses, after both oral and intraperitoneal acute administration. Structural modifications (moderate lymphocytolysis) were identified only in the spleen at the highest tested dose. In conclusion, the thiazolo arene ruthenium complex was very well tolerated orally and had a low acute toxicity after intraperitoneal administration in Crl:WI rats The results justify further investigation to determine the in vivo therapeutic potential of this promising ruthenium complex.