This article was downloaded by: [Istanbul Universitesi Kutuphane ve Dok] On: 27 August 2013, At: 10:13 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK Analytical Letters Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/lanl20 Flow-Injection Chemiluminescent Determination of Piroxicam Using Tris (2,2′-bipyridyl) Ruthenium(II)—Potassium Permanganate System Fengshan Yu a , Fang Chen a , Shishi Zheng b , Lanhua Chen b & Man Cui c a Department of Chemistry, Hubei Key Laboratory of Bioinorganic Chemistry & Materia Medica, Huazhong University of Science and Technology, Wuhan, China b Department of Chemistry, Huaibei Coal Industry Teachers College, Huaibei, China c Department of Chemistry, School of Chemistry and Chemical Engineering, Anhui University, Hefei, PR China Published online: 05 Nov 2008. To cite this article: Fengshan Yu , Fang Chen , Shishi Zheng , Lanhua Chen & Man Cui (2008) Flow-Injection Chemiluminescent Determination of Piroxicam Using Tris (2,2′- bipyridyl) Ruthenium(II)—Potassium Permanganate System, Analytical Letters, 41:13, 2412-2423, DOI: 10.1080/00032710802352464 To link to this article: http://dx.doi.org/10.1080/00032710802352464 PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform.
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This article was downloaded by: [Istanbul Universitesi Kutuphane ve Dok]On: 27 August 2013, At: 10:13Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH,UK
Analytical LettersPublication details, including instructions forauthors and subscription information:http://www.tandfonline.com/loi/lanl20
Flow-InjectionChemiluminescentDetermination of PiroxicamUsing Tris (2,2′-bipyridyl)Ruthenium(II)—PotassiumPermanganate SystemFengshan Yu a , Fang Chen a , Shishi Zheng b ,Lanhua Chen b & Man Cui ca Department of Chemistry, Hubei Key Laboratory ofBioinorganic Chemistry & Materia Medica, HuazhongUniversity of Science and Technology, Wuhan, Chinab Department of Chemistry, Huaibei Coal IndustryTeachers College, Huaibei, Chinac Department of Chemistry, School of Chemistry andChemical Engineering, Anhui University, Hefei, PRChinaPublished online: 05 Nov 2008.
To cite this article: Fengshan Yu , Fang Chen , Shishi Zheng , Lanhua Chen & Man Cui(2008) Flow-Injection Chemiluminescent Determination of Piroxicam Using Tris (2,2′-bipyridyl) Ruthenium(II)—Potassium Permanganate System, Analytical Letters, 41:13,2412-2423, DOI: 10.1080/00032710802352464
To link to this article: http://dx.doi.org/10.1080/00032710802352464
PLEASE SCROLL DOWN FOR ARTICLE
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Flow-Injection Chemiluminescent Determinationof Piroxicam Using Tris (2,20-bipyridyl)
Ruthenium(II)—Potassium PermanganateSystem
Fengshan Yu,1 Fang Chen,1 Shishi Zheng,2 Lanhua Chen,2 and
Man Cui3
1Department of Chemistry, Hubei Key Laboratory of BioinorganicChemistry & Materia Medica, Huazhong University of Science and
Technology, Wuhan, China2Department of Chemistry, Huaibei Coal Industry Teachers College,
Huaibei, China3Department of Chemistry, School of Chemistry and Chemical
Engineering, Anhui University, Hefei, PR China
Abstract: A rapid and sensitive chemiluminescence method using flow-injectionhas been developed for the determination of an analgesic agent drug, piroxicam.The method is based on the chemiluminescence reaction of piroxicam with anacidic potassium permanganate and Ru(bipy)3
2þ. The chemiluminescence inten-sity is greatly enhanced when quinine sulfate is used as a sensitizer. After optimi-zation of the different experimental parameters, a calibration graph was obtainedover a concentration range of 3.0� 0�8–3.0� 0�5 mol L�1 with the detection limit
Received 9 May 2008; accepted 15 June 2008.The authors acknowledge the support from the National Natural Science
Foundation of China, the Science Foundation of Huazhong University of Science& Technology (0101013008), and the Science Foundation of Huaibei Coal Indus-try Teachers’ College.
Address correspondence to Lanhua Chen, Department of Chemistry, HuaibeiCoal Industry Teachers College, Huaibei 235000, China. E-mail: [email protected]
Analytical Letters, 41: 2412–2423, 2008Copyright # Taylor & Francis Group, LLCISSN: 0003-2719 print=1532-236X onlineDOI: 10.1080/00032710802352464
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of 1.0� 0�8 mol L�1. The relative standard deviation is 1.5% (n¼ 11) for thedetermination of 8.0� 10�7 mol L�1 piroxicam. The proposed method was suc-cessfully applied to commercial tablets, spiked serum, and urine samples.
Keywords: Chemiluminescence, flow-injection, piroxicam, tris (2,20-bipyridyl)ruthenium(II), potassium permanganate
INTRODUCTION
Piroxicam,4-hydroxy-2-methyl-N-(2-pyridinyl)-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide (Fig. 1) is an anonsteroidal antiinflammatory,and analgesic agent drug belonging to a class of compounds called oxi-cams (Goodman et al. 1989). Its efficacy has been demonstrated inhumans for the treatment of various inflammatory diseases and arthropa-thies, such as rheumatoid arthritis and osteoarthritis. Piroxicam acts asan antiinflammatory drug mainly by prostaglandin synthesis inhibition,as well as by leucocyte migration and phagocyte activity inhibition.
Some methods have been reported for the determination of piroxi-cam, including ultraviolet and visible spectrophotometry (UV=Vis) (Heeset al. 2002; Pascual-Reguera, Ayora-Ca~nnada, and Castro-Ruiz 2002),electrochemical (Abbaspour and Mirzajani 2007), amperometry (Silva2007), spectrofluorimetry (Barary et al. 2004; Arancibia and Escandar2003; Escandar, Bystol, and Campiglia 2002; Nagaralli, Seetharamappa,and Melwanki 2002; Amin 2002); liquid chromatography (LC;Dadashzadeh, Vali, and Rezagholi 2002), high-performance liquid chro-matography (HPLC; Doliwa et al. 2001; Jager et al. 1999; Amanlou andDehpour 1997), high-performance liquid chromatography-, ultraviolet,and visible spectrophotometry (HPLC-UV; Basan et al. 2001), liquidchromatography–tandem mass spectrometry method LC-MS=MS (Jiet al. 2005), thin-layer chromatography (TLC)–matrix-assisted laser
Figure 1. Structure of piroxicam.
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desorption (MALDI) TOF mass spectrometry (TLC–MALDI TOF MS;Crecelius 2004), and luminescence (Al-Kindy et al. 2007).
Chemiluminescence (CL) reactions have been used for sensitive,selective, and rapid detection in flow-injections and chromatographicanalysis (Robards and Worsforld 1992). One of the most interesting CLreactions is that involving the oxidation of (2,20-bipyridyl) ruthenium(II),Ru(bipy)3
2þ to Ru(biyp)33þ, which is then followed by reduction with an
analyte species with the subsequent emission of light (Gerardi, Barnett,and Alewis 1999).
This study describes the development of a new simple FI-CL methodfor the determination of piroxicam based on the CL generated by the reac-tion of the drug with Ru(bipy)3
2þ, quinine sulfate, and potassium perman-ganate in a sulfuric acid medium. The proposed method exhibits highprecision and has been successfully applied to the determination of pirox-icam in pharmaceutical tables, spiked serum, and urine samples solution.
EXPERIMENTAL
Apparatus
Figure 2 schematically shows the apparatus used for determination anddetection. Chemiluminescence intensity was recorded by IFFM-D flow-injection luminometry (Remax Electron Technological Ltd, Xian, China;www.xaremex.com). Signal acquisition used a N2000-chromatographyworkstation (Zhejiang University Zhida Information Engineering Ltd.,China; www.54PC.com).
Figure 2. Schematic diagram of the flow injection system a: piroxicam solution;b: KMnO4 (H2SO4) solution; c: Ru(bipy)3
All chemical reagents used were of analytical grade. Piroxicam was obtainedfrom the Institute of Medical Biotechnology (Beijing, China). Piroxicamcapsules were obtained from a drugstore. Ru(bipy)3Br2 was obtained fromSigma (www. Sigma-Aldrich.com). Potassium permanganate was obtainedfrom the Medical Co. of China (Beijing; http://www.sinopharm.com). Sul-furic acid (No. 20061204) was purchased in Xinyang from ChemicalReagents (Henan, China). All other reagents were of analytical grade or bet-ter, and all water used was double-distilled in a fused-silica apparatus.
A stock solution of piroxicam, 1.0� 10�3 mol L�1, was preparedby dissolving 0.0331 g piroxicam with methanol solution and then dilutedto volume with methanol. The working piroxicam solution was preparedby diluting the stock solution with methanol daily. A stock solution ofKMnO4, 0.10 mol L�1 was prepared by dissolving a weighed amountof KMnO4 in water. The working solutions used in experiments wereprepared by diluting the stock standard solutions with water. A stocksolution of Ru(bipy)3Br2, 1.0� 10�3 mol L-1 was prepared by dissolvinga weighed amount of Ru(bipy)3Br2 in water and diluting to volume. Aworking Ru(bipy)3Br2 solution was freshly prepared by diluting the stocksolution. A 0.5 mol L�1 solution of H2 SO4 was prepared by dissolving6.90 mL of concentrated sulfuric acid in 250 mL of water.
Preparation of Samples
Capsule Treatment
The contents of 12 capsules, or finely ground tablets, were weighed andmixed. An amount of the tablet powder or capsule powder equivalentto 20 mg of piroxicam was weighed and dissolved in methanol, and anyremaining residue was removed by filtration. The clear solution wasdiluted to 250 mL with methanol in a 250 mL calibrated flask. The drugcontent of this solution was obtained by applying the general procedureto aliquot that contained an1 appropriate amount of the drug asdescribed above, in order to color and to achieve maximum color devel-opment in the quantitative determination of the examined drugs.
Serum and Urine Treatment
Whole blood samples (20 mL, from local hospital) were centrifuged at4000 rpm for 25 min. The supernatant was aspired to a test tube and usedas a serum sample. An aliquot of standard aqueous solution of the
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studied drug was added to 0.20 mL of fresh urine or 0.20 mL of the serumsample. After mixing for 2 min, it was deproteinized by adding 2.0 mLof 0.10 mol L�1 Ba(OH)2 and 1.8 mL of 0.10 mol L�1 ZnSO4. From this4-mL volume, which was then centrifuged for 10 min at 4000 rpm, 1.0 or0.50 mL of the centrifugate was diluted to 100 mL with water or to a KH2
PO4-NaOH buffer solution and then used for analysis. The absoluterecovery was determined for each drug by comparing the representativeCL intensity of the treated serum or urine samples with the CL intensityof the standard drug at the same concentration.
Procedures
The basic analysis procedure of the batch type CL consisted of the addi-tion of the following quantities of the equilibrated solutions into the reac-tion cell: 0.30 mL Ru(bipy)3Br2 (2.33� 10�4 mol L�1) solution, 0.30 mLpiroxicam (8.33� 10�6 mol L�1) solution, and 0.20 mL quinine sulfate(1.0� 10�2 mol L�1) solution. The contents of the reaction cell wereallowed to mix for more than 5 min in the cell compartment prior tothe injection of 0.20 mL KMnO4 (7.5� 10�3 mol L�1; 0.20 mol L�1 H2
SO4) solution with the injector. The analytical signal was taken as the dif-ference in the CL peak height between a blank and analyte run. The rela-tive CL intensity, DI (defined as the difference of CL intensity betweenpiroxicam standard solution and the blank), was proportional to the con-centration of piroxicam. A calibration curve was prepared for the deter-mination of piroxicam. The luminescence intensity equipment couldcontinuously record peak for quantitative analysis.
RESULTS AND DISCUSSION
Optimization of Experimental Conditions for Piroxicam Detection
A series of experimental conditions were investigated and optimized formaximum CL emission of the Ru(bipy)3Br2-KMnO4–piroxicam system.
The Kinetic Characteristics of the CL Reaction
The CL kinetic characteristics of the reactions were examined using the batchmethod. The CL intensity–time profiles are shown in Fig. 3. A weak CL sig-nal was recorded when Ru(bipy)3Br2 was mixed with KMnO4 mixture solu-tions (Fig. 3a). A strong CL signal was observed when Ru(bipy)3Br2, KMnO4
solutions and piroxicam were present in the reaction system (Fig. 3b).
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Effect of Ru(phen)32þ Concentration
As the same kind of chemiluminescence reagent, the property ofRu(bipy)3
2þ is similar to Ru(phen)32þ. So, the chemiluminescence mech-
anism of Ru(bipy)32þ-KMnO4 –piroxicam system could be described as
follows (He et al. 1999; Meng et al. 1999; Meng, Wu, He, Zeng 1999):
where Piroxicam� indicates the intermediate in the oxidation reactionof the piroxicam and Ru(bipy)3
2þ� indicates the activated complexproduced by the reduction of Ru(bipy)3
2þ. So, the luminophor of thesystem is Ru(bipy)3
2þ. The effect of the concentration of this luminophorto the CL light intensity was investigated with the solutions contain-ing increasing amounts of concentration of Ru(bipy)3
2þ in the range of3.0� 10�6–1.5� 10�4 mol L�1. It was shown that the intensity was
Figure 3. The chemiluminescence kinetic curves of the system in the absence (a)and in the presence (b) of piroxicam conditions: Ru(bipy)3
increased with the increase of the Ru(bipy)32þ concentration, in both the
presence and absence of piroxicam. To minimize reagent consumptionand background, 7.0� 10�5 mol L�1 Ru(bipy)3
2þ was used for thefurther experiments.
Effect of Potassium Permanganate Concentration
As the oxidant, the concentration of KMnO4 could affect the CL inten-sity of the systems and the corresponding experiments were carried outunder the fixed amount of Ru(bipy)3
2þ and H2SO4 and the variationalconcentration of KMnO4 in the range of 3.0� 10�4–3.0� 10�3 molL�1. The experimental results were shown that when the concentrationof KMnO4 increased from 3.0� 10�4 to 1.5� 10�3 mol L�1, the DI value(DI¼ I� I0) that was used to evaluate the enhancement degree of pirox-icam to the CL emission of Ru(bipy)3
2þ–KMnO4 system steadilyincreased. After the concentration of KMnO4 exceeded 1.5� 10�3 molL�1, however, the DI value decreased, which may be due to the absorp-tion of light emission by the colored KMnO4 solution and the scatteringof light emission by the unsolvable hydrolysis product of KMnO4 at theexperimental acidity. In order to obtain the maximum DI value,1.5� 10�3 mol L�1 of KMnO4 was selected for the further experiments.
Effect of Sulfuric Acid Concentration
The CL emission depends on the concentration of H2SO4. The effect ofthe latter was studied in the range 1.0� 10�2–1.2� 10�1 mol L�1 underthe standard conditions given above. The maximum intensity wasobtained at a 4.0� 10�2 mol L�1 H2SO4 concentration. Higher and lowerconcentrations showed lower intensity.
Effect of Sensitizers
Chemiluminescent molecules can potentially transfer their excitationenergy to a fluorophore sensitizer with the subsequent emission of energyby the fluorophore. To study their effect as sensitizers on piroxicam CL,different concentrations (1.0� 10�4� 5.0� 10�3 mol L�1) of Rhodamine6 G, fluorescein, Rhodamine B, and quinine sulfate dissolved in thedrug solution were investigated. It was found that the three sensitizersenhanced the CL signal, but that quinine sulfate showed the highestenhancement. Thus, quinine sulfate was recommended and the maximumCL signal was obtained with a concentration of 2.0� 10�3 mol L�1 quininesulfate.
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Linear Response Range, Detection Limit, and Precision
Under the optimum conditions described above, linearity for the determi-nation of piroxicam was investigated in the range 3.0� 10�8–3.0� 10�5 mol L�1. The regression equation was DI¼ 57.69þ 27.52� 107
107 c (mol L�1), R¼ 0.9994 in the range 3.0� 10�8� 2.5� 10�6 mol L�1,and DI¼ 17.14þ 44.88� 106 c (mol L�1), R¼ 0.9995 in the range2.5� 10�6–3.0� 10�5 mol L�1. The detection limit (3r) for the regressionequation DI¼ 57.69þ 27.52� 107 c (mol L�1) was 1.0� 10�8 mol L�1.The relative standard deviation (R.S.D) is 1.5% for the determinationof 8.0� 10�7 mol L�1 piroxicam (n¼ 11).
A comparison of the analytical performances of the previouslyreported methods and the proposed method for the determination of
Table 1. Comparison of analytical performances of the previously reported meth-ods with the proposed method
tography; LC-MS=MS: liquid chromatography–tandem mass spectrometry method; CL:
Chemiluminescence.
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piroxicam is summarized in Table 1, which shows that the detection limit(DL) of the proposed method was much lower than the previouslyreported methods (Crecelius et al. 2004).
Interference Study
The effect of some common excipients in drugs, metal ions in the humanbody, and several organic compounds on CL intensity was investigatedfor the determination of 2.5� 10�6 mol L�1 piroxicam. The CL emissionsobtained using the piroxicam solution alone and those obtained using thepiroxicam solution with foreign species added were compared. Tolerancewas defined as the amount of foreign species that produced a relativeerror not exceeding �5% in the determination of piroxicam. It can beseen from Table 2 that a 1000-fold excess of Naþ, Kþ, Ca2þ, SO4
2�,and NO3
�; 800-fold excess of maltose and starch; 500-fold excess ofsucrose, lactose, glucose and dextrin; 180-fold excess of EDTA; 120-foldexcess of Fe2þ and Cu2þ; and 40-fold excess of Co2þ did not interferewith the determination of piroxicam in this system.
APPLICATION OF THE METHOD
Analysis of Pharmaceutical Preparations
The proposed method was applied to determine piroxicam in three typesof pharmaceutical preparations, and the results obtained are given inTable 3. There were no significant differences between the labeled con-tents and those obtained by the proposed method.
Table 2. Effect of various additives on CL emission intensity
The sensitivity and detection limit achieved by the CL technique allowsthe determination of piroxicam in serum and urine samples. Humanserum and urine samples were obtained from a healthy volunteer male
Table 4. Determination of piroxicam in spiked human serum sample
in a local hospital (Huaibei, China). To adjust the sample concentrationof the drug to within the linear range of determination, after the deprotei-nization and centrifugation of a serum sample the supernatant was usedto investigate recovery. The standard addition method was used to avoidmatrix effects. The urine samples were diluted appropriately with deio-nized water and analyzed by the standard addition method. The resultsare given in Table 4 and Table 5. Recovery was from 98.0%�102.7%for serum and from 96.7%�101.3% for urine, respectively.
CONCLUSION
The enhancing effect of piroxicam on the tris (2,20-bipyridyl) ruthenium(II) Ru(bipy)3 Br2–KMnO4 CL reaction has been found. The experimen-tal conditions affecting the CL reaction were optimized and the analyticalcharacteristics for the determination of piroxicam have been presented.The proposed method is simple and sensitive and has been applied tothe determination of piroxicam in pharmaceutical capsules, spiked serum,and urine samples.
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