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Hassan AME, El Hamd MA, El-Maghrabey MH, Mahdi WA, Alshehri S, Batakoushy HA. Two Versatile Pencil Graphite-Polymer Sensor Electrodes Coupled with Potentiometry and Potentiometric Titration Methods: Profiling Determinations of Vitamin V in Tablets and Urine Samples. SENSORS (BASEL, SWITZERLAND) 2022; 22:9128. [PMID: 36501827 PMCID: PMC9739328 DOI: 10.3390/s22239128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/11/2022] [Accepted: 11/22/2022] [Indexed: 06/17/2023]
Abstract
Herein, we developed a new pencil graphite ion-selective electrode strategy for the broadly used erectile dysfunction medication, sildenafil citrate (SC, vitamin V), for its automated potentiometry and potentiometric titration profiling in marketed tablets and human urine samples. The method was based on ion-pair complexation between SC and sodium tetraphenylborate (Na-TPB) or phosphotungstic acid (PTA), embedded into a pencil-fabricated graphite sensor electrode coated with poly(vinyl chloride, PVC) matrix, which is pre-plasticized with two different pre-studied plasticizers. The modern fabricated electrodes have a proven fast near-Nernstian response for SC over the concentration range of 1.0 × 10-6 to 1.0 × 10-2 and 1.0 × 10-5 to 1.0 × 10-2 M, with LODs of 6.5 × 10-7 and 5.5 × 10-6 over a pH 3-6 for (SC-TPB)- and (SC-PTA)-based membrane sensors, of O-nitrophenyl octyl ether (O-NPOE) and dioctyl phthalate (DOP), respectively. The selectivity coefficients for different interferents, including many inorganic cations, sugars, and/or nitrogenous compounds, were tested and confirmed. Applications of the proposed method were conducted on the determination of SC in its tablets and urine samples under the proper conditions. The percent recovery values were compared with those obtained by an official method and showed an RSD ≤ 0.3% (n = 5).
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Affiliation(s)
- Abeer M. E. Hassan
- Department of Chemistry, Faculty of Pharmacy, 6 October University, 6th of October City 12585, Egypt
| | - Mohamed A. El Hamd
- Department of Pharmaceutical Sciences, College of Pharmacy, Shaqra University, Shaqra 11961, Saudi Arabia
- Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, South Valley University, Qena 83523, Egypt
| | - Mahmoud H. El-Maghrabey
- Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
| | - Wael A. Mahdi
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia
| | - Sultan Alshehri
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia
| | - Hany A. Batakoushy
- Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Menoufia University, Shebin Elkom 32511, Egypt
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Reis NFA, Silva LFG, Souza MACE, Fialho SL, Souza Moreira CP, Oliveira Andrade MV, Paula WX, Gloria MBA, Pianetti GA, Fernandes C. UHPLC for quality evaluation of genuine and illegal medicines containing sildenafil citrate and tadalafil. J Chromatogr Sci 2021; 59:30-39. [PMID: 33107906 DOI: 10.1093/chromsci/bmaa073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 07/24/2020] [Accepted: 09/06/2020] [Indexed: 11/14/2022]
Abstract
One of the highest incidences of illegal drug products is related to phosphodiesterase-5 inhibitors, used in treatment of erectile dysfunction, including those containing sildenafil citrate and tadalafil. In this context, comprehensive evaluation of the quality of genuine and illegal medicines was performed. A simple and rapid ultra-high performance liquid chromatography (UHPLC-UV) method to quantify sildenafil and tadalafil in the presence of six degradation products was developed and validated. Sildenafil and tadalafil were submitted to forced degradation. The separation was carried out on a Kinetex C18 (50 × 2.1 mm; 1.7 μm) column with mobile phase composed of acetonitrile and aqueous triethylamine solution. The calibration curves were linear in the range of 14-126 μg mL-1 for sildenafil citrate and 4-36 μg mL-1 for tadalafil and the method proved to be selective, precise, accurate and robust. Sildenafil degraded in oxidative media, whereas tadalafil degraded in acidic, alkaline and oxidative environment. The chemical structures and the mechanisms for the formation of the main degradation products were proposed by UHPLC coupled to tandem mass spectrometry. The UHPLC-UV method was applied in the pharmaceutical analysis of genuine and seized medicines. Some of them did not meet quality standards, mainly due to contents below specifications and the large variation on contents between units within a batch.
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Affiliation(s)
- Naialy Fernandes Araújo Reis
- Laboratório de Controle de Qualidade de Medicamentos e Cosméticos, Departamento de Produtos Farmacêuticos, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos 6627, 31270-901 Belo Horizonte, MG, Brazil
| | - Luiz Felipe Gomes Silva
- Laboratório de Controle de Qualidade de Medicamentos e Cosméticos, Departamento de Produtos Farmacêuticos, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos 6627, 31270-901 Belo Horizonte, MG, Brazil
| | - Mateus Araújo Castro E Souza
- Laboratório de Controle de Qualidade de Medicamentos e Cosméticos, Departamento de Produtos Farmacêuticos, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos 6627, 31270-901 Belo Horizonte, MG, Brazil
| | - Sílvia Ligório Fialho
- Serviço de Desenvolvimento Tecnológico Farmacêutico, Diretoria de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias, Rua Conde Pereira Carneiro 80, 30510010 Belo Horizonte, MG, Brazil
| | - Carolina Paula Souza Moreira
- Serviço de Desenvolvimento Tecnológico Farmacêutico, Diretoria de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias, Rua Conde Pereira Carneiro 80, 30510010 Belo Horizonte, MG, Brazil
| | - Marcus Vinicius Oliveira Andrade
- Setor Técnicoe Científico, Superintendência de Polícia Federal, Minas Gerais, Rua Nascimento Gurgel 30, 30430340 Belo Horizonte, MG, Brazil
| | - Washington Xavier Paula
- Instituto de Criminalística, Polícia Civil, Minas Gerais, Avenida Augusto de Lima 1833, 30190-002 Belo Horizonte, MG, Brazil
| | - Maria Beatriz Abreu Gloria
- Laboratório de Controle de Qualidade de Medicamentos e Cosméticos, Departamento de Produtos Farmacêuticos, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos 6627, 31270-901 Belo Horizonte, MG, Brazil
| | - Gerson Antônio Pianetti
- Laboratório de Controle de Qualidade de Medicamentos e Cosméticos, Departamento de Produtos Farmacêuticos, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos 6627, 31270-901 Belo Horizonte, MG, Brazil
| | - Christian Fernandes
- Laboratório de Controle de Qualidade de Medicamentos e Cosméticos, Departamento de Produtos Farmacêuticos, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos 6627, 31270-901 Belo Horizonte, MG, Brazil
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Dural E. Investigation of the Presence of Sildenafil in Herbal Dietary Supplements by Validated HPLC Method. Turk J Pharm Sci 2020; 17:56-62. [PMID: 32454761 DOI: 10.4274/tjps.galenos.2018.91249] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 10/25/2018] [Indexed: 12/01/2022]
Abstract
Objectives As the first FDA-approved phosphodiesterase type 5 inhibitor, sildenafil (SDF) is widely used in the treatment of erectile dysfunction due to its strong pharmacodynamic activity. Since many food supplements are now involved in illegal adulteration, the presence of SDF in food supplements is very important because of their toxicological risks. In this study a simple fast, reliable high-performance liquid chromatography method with ultraviolet (UV) detector has been developed and validated for SDF analysis in herbal dietary supplements (HDSs). Materials and Methods 10 mM phosphate buffer containing 0.1% triethylamine (pH 3.5) and acetonitrile (65:35, v/v), as mobile phase was applied isocratically to a reverse phase C18 analytical (4.6×250 mm, 5 μm) column. Chromatographic separation was achieved by a C18 reverse-phase analytical column 4.6×250 mm, 5 μm particle size, using acetonitrile, with 10 mM phosphate buffer containing 0.1% triethylamine (65:35, v/v, pH 3.5) as a mobile phase. The mobile phase flow rate was 1 mL min-1 and the column temperature was 35°C. The UV detector was set at 293 nm. The liquid-liquid extraction method used in the study provided a simple and practical method for the recovery of SDF in HDSs and their obtained values ranged from 87.6 to 111.7%. Results The method showed linearity with an excellent correlation coefficient (r2>0.999). Moreover, it was specific and sensitive with the limit of quantification, 6.5 ng mL-1. Intraday and interday method precision was ≤8.2 (relative standard deviation %). Intraday and interday method accuracy was between -4.0 and 7.1 (RE%). The method was strong according to the robustness test results obtained from UV detection, mobile phase buffer pH, column temperature, and flow rate changes. The described procedure was simple, fast, precise, and feasible for routine adulteration analysis of SDF, especially in food control or toxicology laboratories. This method was successfully applied to 50 individual solid and liquid form HDSs. Conclusion The results showed that 37 out of 50 samples of HDSs (represented 74.0%) examined contained SDF between 0.01 and 465.47 mg/g, 150.87±127.48 (mean ± standard deviation), which could lead to serious health problems and might even be fatal for consumers. The described procedure was found to be simple, rapid, precise and feasible for routine adulteration analysis of SDF, especially in food control or toxicology laboratories.
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Affiliation(s)
- Emrah Dural
- Sivas Cumhuriyet University, Faculty of Pharmacy, Department of Pharmaceutical Toxicology, Sivas, Turkey
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Luu Y, Thigpen J, Brown SD. Stability of sildenafil in combination with heparin and dopamine. Am J Health Syst Pharm 2017; 74:e64-e71. [PMID: 28007723 DOI: 10.2146/ajhp150853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
PURPOSE The stability of sildenafil in combination with heparin and dopamine was evaluated. METHODS A stability-indicating high-performance liquid chromatography method with ultraviolet detection was developed for sildenafil citrate and validated. The method was applied to the investigation of sildenafil alone, sildenafil with heparin, sildenafil with dopamine, and sildenafil with heparin and with dopamine, all in 5% dextrose injection at room temperature and under refrigeration for 30 days. Samples of 100 μL were pulled from each storage bottle on each sampling day, diluted in mobile phase, and assayed in duplicate. Samples were tested on days 0, 1, 2, 3, 4, 5, 7, 9, 12, 14, 21, and 30. Each preparation was visually inspected for precipitation and color change. The percent recovery in each study sample was determined by comparing the peak area of sildenafil in the sample with the peak area of sildenafil from a freshly prepared 100-μg/mL standard in mobile phase. RESULTS The sildenafil alone, sildenafil with heparin, and sildenafil with dopamine remained within 90-110% of the expected sildenafil potency for at least 30 days at both temperatures. The preparation of sildenafil with both heparin and dopamine fell below 90% potency after 3 days at room temperature and 21 days in the refrigerator. CONCLUSION Sildenafil prepared in 5% dextrose injection alone, with heparin, and with dopamine retained over 90% potency after 30 days of storage at room temperature and under refrigeration. Sildenafil prepared with both heparin and dopamine had a potency of <90% after 3 days of storage at room temperature and 21 days of storage under refrigeration.
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Affiliation(s)
- Yao Luu
- Department of Pharmaceutical Sciences, Bill Gatton College of Pharmacy, East Tennessee State University, Johnson City, TN
| | - Jim Thigpen
- Department of Pharmacy Practice, Bill Gatton College of Pharmacy, East Tennessee State University, Johnson City, TN
| | - Stacy D Brown
- Department of Pharmaceutical Sciences, Bill Gatton College of Pharmacy, East Tennessee State University, Johnson City, TN.
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A new methodology for detection of counterfeit Viagra® and Cialis® tablets by image processing and statistical analysis. Forensic Sci Int 2012; 216:92-6. [DOI: 10.1016/j.forsciint.2011.09.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Revised: 07/29/2011] [Accepted: 09/01/2011] [Indexed: 11/20/2022]
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6
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Sopha H, Hocevar SB, Pihlar B, Ogorevc B. Bismuth film electrode for stripping voltammetric measurement of sildenafil citrate. Electrochim Acta 2012. [DOI: 10.1016/j.electacta.2011.11.049] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Idris AM, Naheid SA, Elgorashe REE, Eltayeb MAH, Al-Akra HN. REVERSED-PHASE SEQUENTIAL INJECTION LIQUID CHROMATOGRAPHIC METHOD FOR SILDENAFIL ASSAY. J LIQ CHROMATOGR R T 2011. [DOI: 10.1080/10826076.2011.587222] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Affiliation(s)
- Abubakr M. Idris
- a Department of Chemistry, College of Science , King Khalid University , Abha, Saudi Arabia
| | - Salih A. Naheid
- b Atomic Energy Council, Sudan Academy of science , Khartoum, Sudan
| | - Rafea E. E. Elgorashe
- a Department of Chemistry, College of Science , King Khalid University , Abha, Saudi Arabia
| | | | - Hussain N. Al-Akra
- d Faculty of Sciences, Department of Chemistry , University of Aleppo , Aleppo, Syria
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Sacré PY, Deconinck E, Chiap P, Crommen J, Mansion F, Rozet E, Courselle P, De Beer JO. Development and validation of a ultra-high-performance liquid chromatography-UV method for the detection and quantification of erectile dysfunction drugs and some of their analogues found in counterfeit medicines. J Chromatogr A 2011; 1218:6439-47. [DOI: 10.1016/j.chroma.2011.07.029] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 06/27/2011] [Accepted: 07/11/2011] [Indexed: 11/28/2022]
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9
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Bunaciu AA, El Nashar RM, Aboul-Enein HY. Mini Review: Determination of Sildenafil Citrate in Pharmaceutical Prepaprations. ANAL LETT 2011. [DOI: 10.1080/00032719.2010.546019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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10
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Ding M, Wu X, Yuan L, Wang S, Li Y, Wang R, Wen T, Du S, Zhou X. Synthesis of core-shell magnetic molecularly imprinted polymers and detection of sildenafil and vardenafil in herbal dietary supplements. JOURNAL OF HAZARDOUS MATERIALS 2011; 191:177-83. [PMID: 21555181 DOI: 10.1016/j.jhazmat.2011.04.058] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 04/02/2011] [Accepted: 04/14/2011] [Indexed: 05/11/2023]
Abstract
An analytical procedure for selective extraction of sildenafil and vardenafil in herbal dietary supplements (HDSs) has been set up by using the magnetic molecularly imprinted polymers (MMIPs) as the extraction and clean-up materials, followed by high performance liquid chromatography-ultraviolet (HPLC-UV). The MMIPs were prepared by a surface molecular imprinting technique, using Fe(3)O(4) magnetite as a magnetically susceptible component, sildenafil as template molecule, 2-(trifluoromethyl) acrylic acid (TFMAA) as functional monomer, ethylene glycol dimethacrylate (EGDMA) as polymeric matrix components. The MMIPs were characterized by transmission electron microscope (TEM), Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM), respectively. The heterogeneity of the MMIPs was modeled with the Freundlich isotherm equation. The resulting MMIPs had high recognition ability and fast binding kinetics for sildenafil. The MMIPs were used as dispersive solid-phase extraction (DSPE) materials to selectively extract sildenafil and vardenafil from HDSs, the contents of sildenafil and vardenafil were found to be 8.05 and 3.86 μg g(-1), respectively, and the average recoveries in spiked HDSs were 70.91-91.75% with a relative standard deviation (R.S.D.) below 7%. The MMIPs were successfully used to selectively enrich and determine sildenafil and vardenafil from HDSs.
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Affiliation(s)
- Meijuan Ding
- School of Pharmacy, Nanjing Medical University, Nanjing, PR China.
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11
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Simultaneous Determination of Seven Adulterants in Slimming Functional Foods by HPLC–ESI–MS/MS. FOOD ANAL METHOD 2011. [DOI: 10.1007/s12161-010-9192-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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12
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Letter to the Editor. Mol Biotechnol 2010. [DOI: 10.1007/s12033-010-9301-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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13
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Cai Y, Cai TG, Shi Y, Cheng XL, Ma LY, Ma SC, Lin RC, Feng W. SIMULTANEOUS DETERMINATION OF EIGHT PDE5-IS POTENTIALLY ADULTERATED IN HERBAL DIETARY SUPPLEMENTS WITH TLC AND HPLC-PDA-MS METHODS. J LIQ CHROMATOGR R T 2010. [DOI: 10.1080/10826076.2010.488979] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Yu Cai
- a School of Pharmacy, Jinan University , Guangzhou, China
| | - Tian-Ge Cai
- b School of Life Science, Liaoning University , Shenyang, China
| | - Yan Shi
- c National Institute for the Control of Pharmaceutical & Biological Products , Beijing, China
| | - Xian-Long Cheng
- c National Institute for the Control of Pharmaceutical & Biological Products , Beijing, China
| | - Ling-Yun Ma
- c National Institute for the Control of Pharmaceutical & Biological Products , Beijing, China
| | - Shuang-Cheng Ma
- c National Institute for the Control of Pharmaceutical & Biological Products , Beijing, China
| | - Rui-Chao Lin
- c National Institute for the Control of Pharmaceutical & Biological Products , Beijing, China
| | - Wei Feng
- c National Institute for the Control of Pharmaceutical & Biological Products , Beijing, China
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Tyszczuk K, Korolczuk M. Voltammetric method for the determination of sildenafil citrate (Viagra) in pure form and in pharmaceutical formulations. Bioelectrochemistry 2010; 78:113-7. [DOI: 10.1016/j.bioelechem.2009.08.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 08/11/2009] [Accepted: 08/11/2009] [Indexed: 10/20/2022]
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15
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Issa YM, El-Hawary WF, Youssef AFA, Senosy AR. Spectrophotometric determination of sildenafil citrate in pure form and in pharmaceutical formulation using some chromotropic acid azo dyes. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2010; 75:1297-1303. [PMID: 20129817 DOI: 10.1016/j.saa.2009.12.068] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Revised: 12/17/2009] [Accepted: 12/31/2009] [Indexed: 05/28/2023]
Abstract
Two simple and highly sensitive spectrophotometric methods were developed for the quantitative determination of the drug sildenafil citrate (SC), Viagra, in pure form and in pharmaceutical formulations, through ion-associate formation reactions (method A) with mono-chromotropic acid azo dyes, chromotrope 2B (I) and chromotrope 2R (II) and ion-pair reactions (method B) with bi-chromotropic acid azo dyes, 3-phenylazo-6-o-carboxyphenylazo-chromotropic acid (III), bis-3,6-(o-hydroxyphenylazo)-chromotropic acid (IV), bis-3,6-(p-N,N-dimethylphenylazo)-chromotropic acid (V) and 3-phenylazo-6-o-hydroxyphenylazo-chromotorpic acid (VI). The reaction products, extractable in methylene chloride, were quantitatively measured at 540, 520, 540, 570, 600 and 575 nm using reagents, I-VI, respectively. The reaction conditions were studied and optimized. Beer's plots were linear in the concentration ranges 3.3-87.0, 3.3-96.0, 5.0-115.0, 2.5-125.0, 8.3-166.7 and 0.8-15.0 microg mL(-1) with corresponding molar absorptivities 1.02 x 10(4), 8.34 x 10(3), 6.86 x 10(3), 5.42 x 10(3), 3.35 x 10(3) and 2.32 x 10(4)Lmol(-1) cm(-1) using reagents I-VI, respectively. The limits of detection and Sandell's sensitivities were calculated. The methods were successfully applied to the analysis of commercial tablets (Vigoran) and the recovery study reveals that there is no interference from the common excipients that are present in tablets. Statistical comparison of the results was performed with regard to accuracy and precision using Student's t- and F-tests at 95% confidence level. There is no significant difference between the reported and proposed methods with regard to accuracy and precision.
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Affiliation(s)
- Y M Issa
- Chemistry Department, Faculty of Science, Cairo University, Giza, Egypt.
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Trefi S, Gilard V, Balayssac S, Malet-Martino M, Martino R. The usefulness of 2D DOSY and 3D DOSY-COSY 1H NMR for mixture analysis: application to genuine and fake formulations of sildenafil (Viagra). MAGNETIC RESONANCE IN CHEMISTRY : MRC 2009; 47 Suppl 1:S163-S173. [PMID: 19655367 DOI: 10.1002/mrc.2490] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Two-dimensional diffusion ordered spectroscopy (DOSY) (1)H NMR is proposed to analyze drugs that are complex mixtures in order to discriminate genuine from fake formulations. The method was applied to the analysis of 17 formulations of sildenafil, one being genuine Viagra and the others illegally manufactured formulations of this drug coming from India, Syria and China. It enabled (i) distinguishing imitations or counterfeit from the authentic formulation, (ii) detecting the presence of sildenafil or adulterants, (iii) gaining information on the formulation process by detection of various excipients, thus giving a precise and global 'signature' of the manufacturer. Even though some samples are slightly overdosed, the quality of products manufactured in India and Syria was better than that of Chinese formulations which were adulterated with vardenafil and homosildenafil. This study also presents a three-dimensional DOSY-COSY (1)H NMR experiment that provides both virtual separation and structural information.
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Affiliation(s)
- Saleh Trefi
- Groupe de RMN Biomédicale, Laboratoire SPCMIB (UMR CNRS 5068), Université Paul Sabatier, 31062 Toulouse cedex, France
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Carlucci G, Ruggieri F, Palumbo G, Mazzeo P. Development of a Liquid Chromatographic Method for the Determination of Sildenafil in Seminal Plasma. J LIQ CHROMATOGR R T 2009. [DOI: 10.1081/jlc-200032665] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Giuseppe Carlucci
- a Dipartimento di Scienze del Farmaco, Facoltà di Farmacia , Università “G. D'Annunzio” Chieti , Via dei Vestini, 66100 , Chieti , Italy
| | - Fabrizio Ruggieri
- b Dipartimento di Chimica, Ingegneria Chimica e Materiali , Università dell'Aquila , Coppito , L'Aquila , Italy
| | - Giancarlo Palumbo
- c Dipartimento di Medicina Interna e Sanità Pubblica , Cattedra di Farmacologia, Università dell'Aquila , San Sisto , L'Aquila , Italy
| | - Pietro Mazzeo
- b Dipartimento di Chimica, Ingegneria Chimica e Materiali , Università dell'Aquila , Coppito , L'Aquila , Italy
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Affiliation(s)
- Shulamit Levin
- a Analytical Department , Medtechnica Inc. , Efal St. 5 Kiriat Arye, Petach Tikva , Israel , 49002
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Aboul‐Enein HY, Hefnawy MM. Rapid Determination of Sildenafil Citrate in Pharmaceutical Preparations Using Monolithic Silica HPLC Column. J LIQ CHROMATOGR R T 2007. [DOI: 10.1081/jlc-120025052] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Hassan Y. Aboul‐Enein
- a Pharmaceutical Analysis Laboratory, Biological and Medical Research Department (MBC‐03) , King Faisal Specialist Hospital and Research Centre , P.O. Box 3354, Riyadh , 11211 , Saudi Arabia
| | - Mohamed M. Hefnawy
- a Pharmaceutical Analysis Laboratory, Biological and Medical Research Department (MBC‐03) , King Faisal Specialist Hospital and Research Centre , P.O. Box 3354, Riyadh , 11211 , Saudi Arabia
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Ali I, Aboul‐Enein HY. Fast Determination of Haloperidol in Pharmaceutical Preparations Using HPLC with a Monolithic Silica Column. J LIQ CHROMATOGR R T 2007. [DOI: 10.1080/10826070500330703] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Imran Ali
- a National Institute of Hydrology , Roorkee, India
| | - Hassan Y. Aboul‐Enein
- b Centre for Clinical Research (MBC‐03‐65) , King Faisal Specialist Hospital and Research Center , Riyadh, Saudi Arabia
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Ergun B, Saracoglu A, Ilgin S, Atkosar Z, Kircali K, Altiokka G. Validation of a Reversed‐Phase HPLC Method for the Analysis of Sildenafil Citrate in Pharmaceutical Preparations and in Spiked Human Plasma. J LIQ CHROMATOGR R T 2007. [DOI: 10.1081/jlc-200058345] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Bülent Ergun
- a Department of Pharmaceutical Toxicology, Faculty of Pharmacy , Anadolu University , Eskisehir, Turkey
| | - Ahmet Saracoglu
- a Department of Pharmaceutical Toxicology, Faculty of Pharmacy , Anadolu University , Eskisehir, Turkey
| | - Sinem Ilgin
- a Department of Pharmaceutical Toxicology, Faculty of Pharmacy , Anadolu University , Eskisehir, Turkey
| | - Zeki Atkosar
- b Department of Analytical Chemistry, Faculty of Pharmacy , Anadolu University , Eskisehir, Turkey
| | - Kevser Kircali
- b Department of Analytical Chemistry, Faculty of Pharmacy , Anadolu University , Eskisehir, Turkey
| | - Göksel Altiokka
- b Department of Analytical Chemistry, Faculty of Pharmacy , Anadolu University , Eskisehir, Turkey
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22
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Liu SP, Fan L, Hu XL, Liu ZF, Li S. Resonance Rayleigh-Scattering Method for the Determination of Sildenafil Citrate in a Pharmaceutical Formulation Using Evans Blue. ANAL SCI 2006; 22:819-23. [PMID: 16772678 DOI: 10.2116/analsci.22.819] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A highly sensitive resonance Rayleigh-scattering (RRS) method for the determination of sildenafil citrate has been developed, based on the fact that sildenafil (Sild) reacted with Evans Blue (EB) to form an ion-association complex in pH 1.1 - 4.6 aqueous solution. This resulted in a significant enhancement of the RRS intensity, and a new spectrum appeared. The wavelength of the maximum RRS was at 365 nm, and other scattering peaks were at 400, 442, 470 and 534 nm, respectively. The intensity of RRS was directly proportional to the concentration of Sild in the range 0 - 11.5 microg ml(-1), and the detection limit for Sild (3 sigma) was 30.3 ng ml(-1). The composition of the ion-association complex was Sild:EB = 1:1, as established by Job's method. The method had good selectivity and could be applied to the determination of Sild in the aqueous phase without using organic solvent extraction. The method was simple and rapid. In addition, the reaction mechanism and the reason for RRS enhancement were considered.
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Affiliation(s)
- Shao-Pu Liu
- School of Chemistry and Chemical Engineering, Southwest China Normal University, Chongqing, P. R. China.
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23
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Zhu X, Xiao S, Chen B, Zhang F, Yao S, Wan Z, Yang D, Han H. Simultaneous determination of sildenafil, vardenafil and tadalafil as forbidden components in natural dietary supplements for male sexual potency by high-performance liquid chromatography-electrospray ionization mass spectrometry. J Chromatogr A 2005; 1066:89-95. [PMID: 15794558 DOI: 10.1016/j.chroma.2005.01.038] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A high-performance liquid chromatographic method coupled with ultraviolet detection and electrospray ionization mass spectrometry (HPLC-UV-ESI-MS) was developed for simultaneous determination of banned additives-sildenafil, vardenafil and tadalafil in dietary supplements for male sexual potency. The separation was achieved on a C18 column with acetonitrile and aqueous solution (20 mmol ammonium acetate, 0.2% formic acid) as mobile phase at a flow rate of I ml/min with a linear gradient program. UV detection was at 292 nm. Identification of drugs was accomplished using ESI-MS. Good linearity between response (peak area) and concentration was found over a concentration range of 0.8-80 microg/ml for sildenafil; 2.25-225 microg/ml for vardenafil; and 1.1-110 microg/ml for tadalafil, with regression coefficient is better than 0.999. The recovery of the method ranged from 93.3 to 106.1%, and the relative standard deviation varied from 2.0 to 5.6% (n = 6). The method has been successfully applied to the analysis of practical samples of natural dietary supplements.
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Affiliation(s)
- Xiaolan Zhu
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research, Ministry of Education, Hunan Normal University, Changsha 410081, China
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24
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Wawer I, Pisklak M, Chilmonczyk Z. 1H, 13C, 15N NMR analysis of sildenafil base and citrate (Viagra) in solution, solid state and pharmaceutical dosage forms. J Pharm Biomed Anal 2005; 38:865-70. [PMID: 16087048 DOI: 10.1016/j.jpba.2005.01.046] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2004] [Revised: 12/22/2004] [Accepted: 01/25/2005] [Indexed: 11/28/2022]
Abstract
Sildenafil citrate (SC) (Viagra) and sildenafil base in pure form are easily and unequivocally characterized by multinuclear NMR spectroscopy. Analysis of chemical shifts indicates that: (i) N6-H forms intramolecular hydrogen bonds, (ii) N25 is protonated in the salt and (iii) intermolecular OH...N hydrogen bonds involving N2 and N4 are present in the solid sildenafil citrate. 13C CPMAS NMR method has been proposed for the identification and quantitation of Viagra in its pharmaceutical formulations.
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Affiliation(s)
- Iwona Wawer
- Department of Physical Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1, 02097 Warsaw, Poland.
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25
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Özkan SA, Uslu B, Zuman P. Electrochemical oxidation of sildenafil citrate (Viagra) on carbon electrodes. Anal Chim Acta 2004. [DOI: 10.1016/j.aca.2003.09.033] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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26
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Nagaraju V, Sreenath D, Rao JT, Rao RN. Separation and determination of synthetic impurities of sildenafil (Viagra) by reversed-phase high-performance liquid chromatography. ANAL SCI 2003; 19:1007-11. [PMID: 12880083 DOI: 10.2116/analsci.19.1007] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A simple and rapid high-performance liquid chromatographic method for the separation and determination of process-related impurities of sildenafil was developed. The separation was achieved on a reversed-phase C18 column using acetonitrile-0.05 M potassium dihydrogen orthophosphate (70:30 v/v) as a mobile solvent at a flow rate of 1.0 ml/min and UV detection at 230 nm. The method was used not only for quality assurance, but also for monitoring the chemical reactions during the synthesis of sildenafil. It was found to be specific, precise and reliable for the determination of all process-related impurities of sildenafil in bulk drugs and formulations.
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Affiliation(s)
- Velupula Nagaraju
- Chemistry Section, A. P. State Forensic Science Laboratory, Red Hills, Hyderabad-500 004, India
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