High‐throughput method for the analysis of venlafaxine in pharmaceutical formulations and biological fluids,using a tris(2,2′‐bipyridyl) ruthenium(II)–peroxydisulphate chemiluminescence system in a two‐chip device

A simple, rapid and sensitive chemiluminescent (CL) method for the assay of venlafaxine (VEN) in pharmaceutical formulations and serum samples by a two‐chip device is proposed. The method is based on the reaction of this drug with a tris(2,2′‐bipyridyl) ruthenium(II)–peroxydisulphate CL system. The optimum chemical conditions for CL emission were investigated. The calibration graph was linear for the concentration range 0.02–8.0 µg/mL. The detection and quantification limits were found to be 0.006 and 0.018 µg/mL, respectively, while the relative standard deviation (RSD) was <2.0%. The present CL procedure was applied to the determination of VEN in pharmaceutical formulations and serum samples; the recovery levels were in the range 96.5–101.2%. The results suggest that the method is unaffected by the presence of common formulation excipients found in these samples. Copyright © 2012 John Wiley & Sons, Ltd.     

Fluorimetric determination of proteins using 4‐chloro‐(2′‐hydroxylophenylazo)rhodanine–Ti(IV) complex as a spectral probe

A novel method for the determination of proteins was developed, based on the enhancement of fluorescence with 4‐chloro‐(2′‐hydroxylophenylazo)rhodanine–Ti(IV) [ClHARP–Ti(IV)] complex as a fluorescence probe. The excitation and emission wavelengths of the system were 335 nm and 376 nm, respectively. The presence of bis(2‐ethylhexyl)sulphosuccinate sodium salt (AOT) microemulsion greatly increased the sensitivity of the system. Under optimal conditions, four kinds of proteins, including bovine serum albumin (BSA), human serum albumin (HSA), egg albumin (Ova), and γ‐globin (γ‐G) were studied. The detection limits were 0.182 µg/mL for BSA, 0.0788 µg/mL for HSA, 0.216 µg/mL for Ova and 0.484 µg/mL for γ‐G. The linear ranges of the calibration were 0–12.0, 0–10.0, 0–18.0 and 0–18.0 µg/mL, respectively. The method possessed high sensitivity, good selectivity and was applied to the analysis of protein in milk powder and cornmeal with satisfactory results. Copyright © 2008 John Wiley & Sons, Ltd.     

Study on the interaction between palladium(II)–lincomycin chelate and erythosine by absorption,fluorescence and resonance Rayleigh scattering spectra and its analytical applications

In pH 5.0–5.4 HAc–NaAc buffer solution, lincomycin (Linco) reacted with Pd(II) to form 1:1 cationic chelate, which could further react with erythrosine (Ery) to form 1:1 ion‐association complexes (Pd–Linco)Ery. As a result, not only were the absorption and fluorescence spectra changed, but also the resonance Rayleigh scattering (RRS) intensity was greatly enhanced. These phenomena offered useful means for the determination of Linco by spectrophotometry, fluorescence and RRS methods. The linear range and detection limit of Linco were 0.20–3.00 µg/mL and 0.057 µg/mL, 0.20–4.80 µg/mL and 0.061 µg/mL, 0.05–2.70 µg/mL and 0.015 µg/mL for the spectrophotometric, fluorescence quenching and RRS methods, respectively. Among these, the RRS method obtained the highest sensitivity. Therefore, the optimum reaction conditions and the influences of coexisting substances were investigated using the RRS method. A simple, sensitive and rapid method has been developed for the determination of Linco in either the pharmaceutical form or human body fluids, and the reasons for RRS enhancement are discussed. Copyright © 2008 John Wiley & Sons, Ltd.     

Determination of sulpiride in pharmaceutical preparations and biological fluids using a Cr (III) enhanced chemiluminescence method

A highly sensitive and simple method for identifying sulpiride in pharmaceutical formulations and biological fluids is presented. The method is based on increased chemiluminescence (CL) intensity of a luminol–H₂O₂ system in response to the addition of Cr (III) under alkaline conditions. The CL intensity of the luminol–H₂O₂–Cr (III) system was greatly enhanced by the addition of sulpiride and the CL intensity was proportional to the concentration of sulpiride in a sample solution. Various parameters affecting the CL intensity were systematically investigated and optimized for determination of the sulpiride in a sample. Under the optimum conditions, the CL intensity was proportional to the concentration of sulpiride in the range of 0.068–4.0 µg/mL, with a good correlation coefficient of 0.997. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 8.50 × 10^‐6 µg/mL and 2.83 × 10^‐5 µg/mL, respectively. The method presented here produced good reproducibility with a relative standard deviation (RSD) of 2.70% (n = 7). The effects of common excipients and metal ions were studied for their interference effect. The method was validated statistically through recovery studies and successfully applied for the determination of sulpiride in pure form, pharmaceutical preparations and spiked human plasma samples. The percentage recoveries were found to range from 99.10 to 100.05% for pure form, 98.12 to 100.18% for pharmaceutical preparations and 97.9 to 101.4% for spiked human plasma. Copyright © 2012 John Wiley & Sons, Ltd.     

Flow‐injection chemiluminescent determination of estrogen benzoate using the tris(1,10‐phenanthroline) ruthenium(II)–permanganate system

Chemiluminescence (CL) detection for the determination of estrogen benzoate, using the reaction of tris(1,10–phenanthroline)ruthenium(II)–Na₂SO₃–permanganate, is described. This method is based on the CL reaction of estrogen benzoate (EB) with acidic potassium permanganate and tris(1,10–phenanthroline)ruthenium(II). The CL intensity is greatly enhanced when Na₂SO₃ is added. After optimization of the different experimental parameters, a calibration graph for estrogen benzoate is linear in the range 0.05–10 µg/mL. The 3 s limit of detection is 0.024 µg/mL and the relative standard deviation was 1.3% for 1.0 µg/mL estrogen benzoate (n = 11). This proposed method was successfully applied to commercial injection samples and emulsion cosmetics. The mechanism of CL reaction was also studied. Copyright © 2011 John Wiley & Sons, Ltd.     

Flow‐injection analysis for meloxicam based on tris(2,2′‐bipyridine) ruthenium(II)–Ce(IV) chemiluminescent system

It was found that meloxicam could enhance the chemiluminescence (CL) of the tris(2,2'‐bipyridine) ruthenium(II)–Ce(IV) system in the medium of sulfate acid. Based on this phenomenon a new flow‐injection system with chemiluminescent detection has been proposed for determination of meloxicam. Under optimum conditions, meloxicam had a good linear relationship with the CL intensity in the concentration range of 6.0  10^?4 to 1.0 µg/mL and the detection limit was 3.7 × 10^?4 µg/mL. The proposed method was applied to detect meloxicam in tablets and a satisfactory recovery was obtained. The possible mechanism for this CL system is also discussed in this paper. Copyright © 2009 John Wiley & Sons, Ltd.     

Study of the enhancement of a new chemiluminescence reaction and its application to determination of β‐lactam antibiotics

An enhanced thiosemicarbazide(TSC)–H₂O₂ chemiluminescence (CL) system was established and proposed as a new analytical method for determination of β‐lactam antibiotics, ampicillin sodium and amoxicillin at microgram levels. The method is based on the inhibition of CL emission accompanying oxidation of TSC by H₂O₂ in alkaline medium. The effect of anionic, cationic, and non‐ionic surfactants on the CL emission of the system was studied. Both N‐cetyl‐N,N,N‐trimethylammonium bromide (CTMAB) and Triton X‐100, unlike sodium dodecyl sulfate (SDS), reinforced the CL intensity and were efficient to approximately the same level. The effect of the presence of eight non‐aqueous solvents on the CL system was also investigated. Upon addition of both of the non‐ionic surfactant, Triton X‐100, and the non‐aqueous solvent, N,N‐dimethyl formamide (DMF), the intensity of the CL reaction was increased 100‐fold. This method allows the measurement of 25–545 µg amoxicillin, and 35–350 µg ampicillin sodium. The detection limits are 8 µg for amoxicillin and 9 µg for ampicillin sodium. The relative standard deviations of six replicate measurements of 200 µg amoxicillin and 200 µg ampicillin sodium were 1.9 and 2.1%, respectively. The effect of foreign species on the determination of amoxicillin and ampicillin sodium was also examined. The proposed method was successfully applied to the determination of ampicillin sodium and amoxicillin in some pharmaceutical dosage forms. Copyright © 2008 John Wiley & Sons, Ltd.     

Chemiluminescence method for the determination of piroxicam by the enhancement of the tris‐(4,7‐diphenyl‐1,10‐phenanthrolinedisulphonic acid) ruthenium(II) (RuBPS)–cerium(IV) system and its application

A simple, rapid chemiluminescence (CL) method was described for the determination of piroxicam, a commonly used analgesic agent drug. A strong CL signal was detected when cerium(IV) sulphate was injected into tris‐(4,7‐diphenyl‐1,10‐phenanthrolinedisulphonic acid) ruthenium(II) (RuBPS)–piroxicam solution. The CL signal was proportional to the concentration of piroxicam in the range 2.8 × 10^–8–1.2 × 10^–5 mol/L. The detection limit was 2 × 10^–8 mol/L and the relative standard deviation (RSD) was 3.7% (c = 7.0 × 10^–7 mol/L piroxicam; n = 11). The proposed method was applied to the determination of piroxicam in pharmaceutical preparations in capsules, spiked serum and urine samples with satisfactory results. Copyright © 2008 John Wiley & Sons, Ltd.     

Determination of phenformin hydrochloride using molecular imprinting technology coupled with flow-injection chemiluminescence

A novel method was developed using molecular imprinting technology (MIT) coupled with flow‐injection chemiluminescence (FI‐CL) for highly sensitive detection of phenformin hydrochloride (PH). The phenformin imprinted polymer was synthesized with methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as a cross‐linker. Newly synthesized molecularly imprinted polymer (MIP) particles were packed into a column as a selective recognition element for determination of PH. A CL method for the determination of PH was developed based on the CL reaction of PH with N‐bromosuccinimide sensitized by eosin Y in basic media. The optimization of detection conditions was investigated. The CL intensity responded linearly to the concentration of PH in the range 0.09–2.0 µg/mL, with a correlation coefficient of 0.9920. The detection limit was 0.031 µg/mL. The relative standard deviation for the determination of 1.0 µg/mL PH solution was 1.0% (n = 11). The method was applied to the determination of PH in urine samples, with satisfactory results. Copyright © 2011 John Wiley & Sons, Ltd.     

Flow injection determination of diclofenac sodium based on its sensitizing effect on the chemiluminescent reaction of acidic potassium permanganate–formaldehyde

A sensitive and simple chemiluminescent (CL) method for the determination of diclofenac sodium has been developed by combining the flow injection technique and its sensitizing effect on the weak CL reaction between formaldehyde and acidic potassium permanganate. A calibration curve is constructed for diclofenac sodium under optimized experimental parameters over the range 0.040–5.0 µg/mL and the limit of detection is 0.020 µg/mL (3σ). The inter‐assay relative standard deviation for 0.040 µg/mL diclofenac sodium (n = 11) is 2.0%. This method is rapid, sensitive, simple, and shows good selectivity and reproducibility. The proposed method has been successfully applied to the determination of the studied diclofenac sodium in pharmaceutical preparations with satisfactory results. Furthermore, the possible mechanism for the CL reaction has been discussed in detail on the basis of UV and CL spectra. Copyright © 2014 John Wiley & Sons, Ltd.     

Determination of clomipramine by flow‐injection analysis with acidic potassium permanganate–formic acid chemiluminescence detection

A sensitive and simple chemiluminescent (CL) method for the determination of clomipramine has been developed by combining the flow‐injection analysis (FIA) technique, which is based on the CL intensity generated from the redox reaction of potassium permanganate (KMnO₄)–formic acid in sulphuric acid (H₂SO₄) medium. Under the optimum conditions, the linear range for the determination of clomipramine was 0.04–4 µg/mL, with a correlation coefficient of 0.9988 (n = 10) and a detection limit of 0.008 µg/mL (3σ), and the relative standard deviation (RSD) for 2.0 µg/mL clomipramine (n = 11) is 1.26%. The proposed method has been successfully applied to the determination of the studied clomipramine in pharmaceutical preparations. The possible reaction mechanism is discussed. Copyright © 2011 John Wiley & Sons, Ltd.     

Determination of carbamazepine in human urine and serum samples by high‐performance liquid chromatography with post‐column Ru(bipy)‐Ce(SO4)2 chemiluminescence detection

A novel, sensitive and rapid CL method coupled with high‐performance liquid chromatography separation for the determination of carbamazepine is described. The method was based on the fact that carbamazepine could significantly enhance the chemiluminescence of the reaction of cerium sulfate and tris(2,2‐bipyridyl) ruthenium(II) in the presence of acid. The chromatographic separation was performed on a Kromasil® (Sigma‐Aldrich) TM RP‐C18 column (id: 150 mm × 4.6 mm, particle size: 5 µm, pore size: 100 Å) with a mobile phase consisting of methanol–water‐glacial acetic acid (70:29:1, v/v/v) at a flowrate of 1.0 mL/min, the total analysis time was within 650 s. Under optimal conditions, CL intensity was linear for carbamazepine in the range 2.0 × 10^?8 ~ 4.0 × 10^?5 g/mL, with a detection limit of 6.0 × 10^?9 g/mL (S/N = 3) and the relative standard detection was 2.5% for 2.0 × 10^?6 g/mL (n = 11). This method was successfully applied to the analysis of carbamazepine in human urine and serum samples. The possible mechanism of the CL reaction is also discussed briefly. Copyright © 2012 John Wiley & Sons, Ltd.     

Determination of alkaloids in Sinomenium acutum by field‐amplified sample stacking in capillary electrophoresis with chemiluminescene detection

A simple and rapid capillary electrophoresis (CE) with an acidic potassium permanganate chemiluminescence (CL) detection method was developed to determine three alkaloids (curine, sinomenine and magnoflorine) simultaneously. A laboratory‐built CE–CL detection interface was used. The field‐amplified sample stacking technique was applied to the online concentration of alkaloids. Experimental conditions for CE separation and CL detection were investigated in detail to acquire optimum conditions. Under optimal conditions, the three alkaloids were baseline separated within 6 min, and the detection limits (S/N = 3) ranged from 0.03 µg/mL to 0.49 µg/mL. This method was successfully applied to determine the above three alkaloids in Sinomenium acutum, and the result of the determination of sinomenine was in good agreement with those given by high‐performance liquid chromatography and CE methods. In addition, a possible CL reaction mechanism of sinomenine–KMnO₄–H₂SO₄ was proposed. Copyright © 2013 John Wiley & Sons, Ltd.     

Analysis of fexofenadine in pharmaceutical formulations using tris(1,10‐phenanthroline)–ruthenium(II) peroxydisulphate chemiluminescence system in a multichip device

A simple, rapid and sensitive method has been developed for the analysis of fexofenadine (FEX) in pharmaceutical formulations, using a tris(1,10‐phenanthroline)–ruthenium(II) [Ru(phen)₃²⁺] peroxydisulphate chemiluminescence (CL) system in a multichip device. Various parameters that influence the CL signal intensity were optimized. These included pH, flow rates and concentration of reagents used. Under optimum conditions, a linear calibration curve in the range 0.05–5.0 µg/mL was obtained. The detection limit was found to be 0.001 µg/mL. The procedure was applied to the analysis of FEX in pharmaceutical products and was found to be free from interference from concomitants usually present in these preparations. Copyright © 2011 John Wiley & Sons, Ltd.     

Simple chemiluminescence determination of ketotifen using tris(1,10 phenanthroline)ruthenium(II)‐ Ce(IV) system

A new method using chemiluminescence (CL) detection has been developed for the simple determination of ketotifen fumarate (KF). The method is based on the catalytic effect of KF in the CL reaction of tris(1,10 phenanthroline)ruthenium(II), Ru(phen)₃²⁺, with Ce(IV) in sulfuric acid medium. The CL response was detected using a lab‐made chemiluminometer. Effects of chemical variables were investigated and under optimum conditions, the CL intensity was proportional to the concentration of the drug over the range 0.34‐34.00 µg mL^?1 KF. The limit of detection (S/N=3) was 0.09 µg mL^?1. Effects of common ingredients were investigated and the method was applied successfully for determining KF in pharmaceutical formulations and human plasma. The percent of relative standard deviation (n=11) at level of 3.4 µg mL^?1 of KF was 4.6% and the minimum sampling rate was 70 samples per hour. The possible CL mechanism is proposed based on the kinetic characteristic of the CL reaction, CL spectrum, UV‐Vis and phosphorescence spectra. Copyright © 2015 John Wiley & Sons, Ltd.     

Comparison of colorimetric and chemiluminescent enzyme‐linked immunosorbent assay for the detection of endosulfan in food samples

Pesticides have become part of food protection since their inception. Endosulfan, an organochlorine insecticide, has been used against insect pests such as whiteflies, aphids, red spiders and mites. Methods of immunochemical assays have been devised for the determination and analysis of pesticides and commonly used for the analysis of contaminants in food, water, soil and body fluids. Chicken IgY antibodies raised against endosulfan haptens were used for the detection of endosulfan. We have compared colorimetric (CO) and chemiluminescence (CL) enzyme‐linked immunosorbent assay (ELISA) techniques for the detection of endosulfan isomers in a food matrix. CL ELISA assay was found to be more sensitive than CO assay. The mean recovery was 81.2–95.6% for α‐ and β‐endosulfan‐spiked food samples with 2.8–4.6% relative standard deviation. The detection of the endosulfan isomers was linear in the range 100 µg/mL–5 fg/mL, with a limit of detection at 100 µg/mL and 5 fg/mL for the CL ELISA method and 100 µg/mL and 1 ng/mL for the CO ELISA method respectively. These methods can be used for the rapid and reliable detection of organochlorine pesticide endosulfan. Copyright © 2015 John Wiley & Sons, Ltd.     

A validated HPLC method for the determination of dimethyl‐4,4′‐dimethoxy‐5,6,5′,6′‐dimethylene dioxybiphenyl‐2,2′‐dicarboxylate (DDB) with fluorescence detection in raw material and pill form: application to an in vitro dissolution test and a content uniformity test

A simple, sensitive and rapid HPLC method with fluorescence detection for the determination of dimethyl‐4,4′‐dimethoxy‐5,6,5′,6′‐dimethylene dioxybiphenyl‐2,2′‐dicarboxylate (DDB) in the raw material and pill form was developed. Liquid chromatography was performed on a C₁₈ column (250 × 4.6 mm i.d., 5 µm particle size), the mobile phase consisted of methanol and 0.05 M sodium dihydrogen phosphate buffer (80 : 20, v/v), and the apparent pH of the mobile phase was adjusted to 3. The fluorescence detector was operated at excitation/emission wavelengths of 275/400 nm. The proposed method allows the determination of DDB within concentration range 0.1–1.5 µg/mL with a limit of detection of 0.032 µg/mL, a limit of quantification of 0.097 µg/mL and a correlation coefficient of 0.9997. The proposed method has been successfully applied for the analysis of DDB in its pills with a percentage recovery of 98.45 ± 0.32. The method was fully validated according to ICH guidelines. Moreover, the high sensitivity of the method permits its use in an in vitro dissolution test for DDB under simulated intestinal conditions. In addition, the proposed method was extended to a content uniformity test according to USP guidelines. Copyright © 2014 John Wiley & Sons, Ltd.     

Flow‐injection chemiluminescence and electrogenerated chemiluminescence determination of escitalopram oxalate in tablet form

Rapid, simple and highly sensitive flow‐injection (FI) chemiluminescence (CL) and flow‐injection electrogenerated chemiluminescence (ECL) methods were developed for the determination of escitalopram oxalate (ESC), a selective serotonin reuptake inhibitor used as an antidepressant drug. The CL method was based on the CL reaction of ESC with acidic cerium(IV) and tris(2,2'‐bipyridyl)ruthenium(II) (Ru). Various experimental parameters affecting CL intensity were carefully studied and optimised. The method enabled the determination of 0.001‐50 µg/mL of ESC in bulk form with a correlation coefficient r = 0.9999. The limit of detection (LOD) was 0.01 ng/mL (S/N = 3). The ECL method was based on the ECL reaction of Ru with the drug in an acidic medium, permitting the determination of ESC in the range of 0.00001‐70 µg/mL with r = 0.9999 and LOD of 1 x 10^‐4 ng/mL. The proposed methods were applied to the determination of ESC in commercial tablets. The results were compared statistically with those obtained from a published method using t‐ and F‐tests. Copyright © 2012 John Wiley & Sons, Ltd.     

One-step method for plasma determination of ibuprofen by chemiluminescence-coupled ultrafiltration and application in a pharmacokinetic study

A simple one‐step method is established for plasma determination of ibuprofen and its pharmacokinetic study. The method involves simple sample pre‐treatment by dilution, rapid separation by ultrafiltration (UF) and online sensitive detection by chemiluminescence (CL) based on significant intensity enhancement of ibuprofen on the weak CL of potassium permanganate and sodium sulphite in an acidic system. The calibration curve for ibuprofen is linear in the range 0.1–50.0 µg/mL in rat plasma. Average recoveries of ibuprofen at 0.80, 12.0 and 40.0 µg/mL amounted to 98.0 ± 4.2%, 101.2 ± 3.6% and 99.3 ± 5.4%, respectively. Standard deviations of intra‐ and inter‐day measurement precision and accuracy are within ±10.0%. The detection limit for ibuprofen is 10.0 µg/L in plasma samples. Pharmacokinetic study of ibuprofen by the validated method shows that the mean plasma drug concentration–time course confirms to a classical two‐compartment open model with first‐order absorption. The proposed method will be an alternative for pre‐clinical pharmacokinetic study of ibuprofen and other non‐steroidal anti‐inflammatory drugs. Copyright © 2011 John Wiley & Sons, Ltd.