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Ali AMBH, Abdel-Aal FAM, Rageh AH, Mohamed AMI. A Comprehensive Review on Analytical Techniques for Determination of Sex Stimulants, PDE5 Inhibitors in Different Matrices with Special Focus on the Electroanalytical Methods. Crit Rev Anal Chem 2022:1-30. [PMID: 36508289 DOI: 10.1080/10408347.2022.2152274] [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: 12/14/2022]
Abstract
Erectile dysfunction (ED) is one of the most common chronic diseases affecting men and its incidence increases with aging. Due to its substantial influence on the quality of life, phosphodiesterase type-5 (PDE5) inhibitors have been implemented to treat ED by increasing the penile blood flow that results in improving erection. PDE5 inhibitors is a class of drugs that affects many pharmacological sectors, and it is essential to review the different analytical methods described for their determination. Few reviews were published concerning this group of drugs. For this reason, this review article gathers the different analytical methods used to determine PDE5 inhibitors in pharmaceutical and biological samples over the past 20 years. Different analytical techniques were used to analyze these compounds in different matrices such as separation methods (capillary electrophoresis, LC-MS, UPLC-MS/MS, and GC-MS), spectroscopic methods (UV-visible methods, FT-IR spectroscopy and spectrofluorometry) and electrochemical methods (polarography, voltammetry and potentiometry). This review focuses on the different electrochemical methods and their use in analytical determination of PDE5 inhibitors in pharmaceutical dosage forms and biological samples. Moreover, it discusses the different modified electrodes used for their electroanalytical determination and the behavior of the studied drugs at different modified electrodes. Additionally, this review discusses the pharmacokinetics of the studied compounds and their interactions with other co-administered drugs especially the metabolic interactions between the studied compounds and other co-administered drugs in different matrices. This literature survey would provide a beneficial guide for future analytical investigation of PDE5 inhibitors.
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Affiliation(s)
- Al-Montaser Bellah H Ali
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Assiut University, Assiut, Egypt
| | - Fatma A M Abdel-Aal
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Assiut University, Assiut, Egypt
| | - Azza H Rageh
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Assiut University, Assiut, Egypt
| | - Abdel-Maaboud I Mohamed
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Assiut University, Assiut, Egypt
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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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Zayed M, Abbas AA, Mahmoud WH, Ali AE, Mohamed GG. Development and surface characterization of a bis(aminotriazoles) derivative based renewable carbon paste electrode for selective potentiometric determination of Cr(III) ion in real water samples. Microchem J 2020. [DOI: 10.1016/j.microc.2020.105478] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Rouhani M, Soleymanpour A. Molecularly imprinted sol-gel electrochemical sensor for sildenafil based on a pencil graphite electrode modified by Preyssler heteropolyacid/gold nanoparticles/MWCNT nanocomposite. Mikrochim Acta 2020; 187:512. [PMID: 32833062 DOI: 10.1007/s00604-020-04482-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 08/04/2020] [Indexed: 10/23/2022]
Abstract
An electrochemical sensor based on the imprinted sol-gel on pencil graphite electrode (PGE) modified with functionalized multiwalled carbon nanotube (MWCNT), gold nanoparticles (AuNPs), and Preyssler heteropolyacid (PHPA) nanohybrid was fabricated for the determination of trace amounts of sildenafil. The pencil graphite electrode was first deposited by the AuNPs@PHPA-MWCNT nanohybrids, and then, the modified electrode of MIP-sol-gel/AuNPs@PHPA-MWCNTs was prepared by the electrochemical method. The synthesized nanohybrids and prepared modified electrodes were characterized with FE-SEM, FTIR, EDX, XRD, and UV/Vis. Cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse voltammetry techniques were applied for the electrochemical analysis using the modified electrodes. By measuring the oxidation and reduction currents of the potassium ferricyanide probe, the efficiency of this sensor was evaluated for the detection of sildenafil. The anodic peak current was measured at 0.2 V vs. Ag/AgCl by differential pulse voltammetry in the potential range - 0.1 to 0.5 V (vs. Ag/AgCl). Under the optimum conditions, the current response for the detection of sildenafil was linear in two concentration ranges of 0.1-2 and 2-30 nM and the obtained limit of detection was 0.033 nM. The constructed sensor was used for the measurement of sildenafil in real samples.
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Affiliation(s)
- Mina Rouhani
- School of Chemistry, Damghan University, Damghan, 3671641167, Iran
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Eman Yossri Frag, Mohamed ME, Elhassan MO. Validated Potentiometric Sensors for Determination of Ramipril in Pharmaceuticals and Biological Fluids using in situ Screen Printed and Carbon Paste Electrodes. JOURNAL OF ANALYTICAL CHEMISTRY 2020. [DOI: 10.1134/s1061934820030041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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A comparative study of tetra-n-butylammonium bromide potentiometric selective screen printed, carbon paste and carbon nanotube modified graphite sensors. JOURNAL OF THE IRANIAN CHEMICAL SOCIETY 2019. [DOI: 10.1007/s13738-019-01825-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Silva TD, Toledo CR, Vianna-Soares CD. Development and validation of alternative methods by non-aqueous acid-base titration and derivative ultraviolet spectrophotometry for quantification of sildenafil in raw material and tablets. BRAZ J PHARM SCI 2017. [DOI: 10.1590/s2175-97902017000115181] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Comparison on physical property, dissolution and disintegration of four launched orally disintegration film (ODF) products for erectile dysfunction. JOURNAL OF PHARMACEUTICAL INVESTIGATION 2014. [DOI: 10.1007/s40005-014-0127-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Wang CC, Gómez RA, Fernandez LP. Determination of sildenafil by preconcentration on surfactant coated polymeric resin followed by spectrofluorimetry. J Pharm Anal 2013; 3:173-179. [PMID: 29403813 PMCID: PMC5760990 DOI: 10.1016/j.jpha.2012.11.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 11/02/2012] [Indexed: 11/25/2022] Open
Abstract
The illicit addition of phosphodiesterase type-5 (PDE-5) inhibitors like sildenafil (Viagra) in product offered as herbal medicine or dietary supplement for male erectile dysfunction has concerned authorities in recent times. In this paper, we proposed a sensitive surfactant-coated Amberlite XAD™ resin for sildenafil preconcentration method with spectrofluorimetric detection. Retention capacity of micellar coated XAD resin for sildenafil was studied and the obtained eluate was measured by spectrofluorometer at excitation and emission wavelengths of 350 and 430 nm, respectively. This method allowed the detection of sildenafil at 0.15 ng/mL with linear range of 0.0003-7.0 μg/mL. The method has been successfully applied to the analysis of some local commercially available herbal medicines and urine.
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Affiliation(s)
- Chien C. Wang
- INQUISAL-CONICET, Chacabuco y Pedernera, 5700-San Luis, Argentina
| | - Roxana A. Gómez
- INQUISAL-CONICET, Chacabuco y Pedernera, 5700-San Luis, Argentina
- Departamento de Farmacia, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Argentina
| | - Liliana P. Fernandez
- INQUISAL-CONICET, Chacabuco y Pedernera, 5700-San Luis, Argentina
- Área de Química Analítica, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Argentina
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Wang CC, Sombra L, Fernández L. Automated flow system for sildenafil enrichment using surfactant coated solid-phase with fluorescence detection. Talanta 2012; 98:247-52. [PMID: 22939155 DOI: 10.1016/j.talanta.2012.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 07/02/2012] [Accepted: 07/02/2012] [Indexed: 11/25/2022]
Abstract
In this work, Amberlite XAD-1180 resin is used for on-line surfactant-mediated pre-concentration of sildenafil as a prior step for its fluorescent detection. In order to activate the column for sildenafil pre-concentration, the cationic surfactant (hexadecyltrimethylammoniunm bromide, HTAB) is adsorbed onto the resin. In these conditions, sildenafil is retained by HTAB-resin and then it is eluted with ethanol and analyzed by spectrofluorimetry. Drug-surfactant association produces a considerable fluorescence enhancement, increasing considerably the sensitivity of detection. Therefore, sildenafil can be pre-concentrated and quantitatively determined, with a detection limit of 0.2 ng mL(-1). The proposed method was successfully applied to the analysis of bulk drug, human urine, tablets, and local herbal medicine. Validation processes were performed by recovering studies and statistical analysis with satisfactory results.
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Potentiometric determination of antihistaminic diphenhydramine hydrochloride in pharmaceutical preparations and biological fluids using screen-printed electrode. Bioelectrochemistry 2011; 82:79-86. [DOI: 10.1016/j.bioelechem.2011.05.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Revised: 05/19/2011] [Accepted: 05/23/2011] [Indexed: 10/18/2022]
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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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14
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Frag EY, Mohamed GG, Alelaiwi HM. Electroanalytical determination of sildenafil in Viagra tablets using screen-printed and conventional carbon paste electrodes. J Electroanal Chem (Lausanne) 2011. [DOI: 10.1016/j.jelechem.2011.03.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Frag EYZ, Mohamed GG, El-Dien FAN, Mohamed ME. Construction and performance characterization of screen printed and carbon paste ion selective electrodes for potentiometric determination of naphazoline hydrochloride in pharmaceutical preparations. Analyst 2011; 136:332-9. [DOI: 10.1039/c0an00343c] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Han WS, Kim JK, Chung KC, Hong JY, Hong JK, Kim JH, Hong TK. Poly(aniline) solid contact ion selective electrode for udenafil. JOURNAL OF ANALYTICAL CHEMISTRY 2010. [DOI: 10.1134/s1061934810100084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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17
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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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Batista ÉF, Sartori ER, Medeiros RA, Rocha-Filho RC, Fatibello-Filho O. Differential Pulse Voltammetric Determination of Sildenafil Citrate (Viagra®) in Pharmaceutical Formulations Using a Boron-Doped Diamond Electrode. ANAL LETT 2010. [DOI: 10.1080/00032710903491153] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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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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de Veij M, Deneckere A, Vandenabeele P, de Kaste D, Moens L. Detection of counterfeit Viagra® with Raman spectroscopy. J Pharm Biomed Anal 2008; 46:303-9. [DOI: 10.1016/j.jpba.2007.10.021] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Revised: 09/20/2007] [Accepted: 10/09/2007] [Indexed: 10/22/2022]
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Bohets H, Vanhoutte K, De Maesschalck R, Cockaerts P, Vissers B, Nagels LJ. Development of in situ ion selective sensors for dissolution. Anal Chim Acta 2007; 581:181-91. [PMID: 17386443 DOI: 10.1016/j.aca.2006.07.079] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2006] [Revised: 07/27/2006] [Accepted: 07/28/2006] [Indexed: 10/24/2022]
Abstract
The dissolution of formulations of the drugs dapoxetine, paliperidone, cinnarizine, tetrazepam, mebeverine, loperamide, galantamine and ibuprofen was studied by an in-line potentiometric measurement system. The transpose of a Nikolskii-Eisenman type function performed the conversion of potential to percentage of dissolution. A novel gradient membrane electrode was developed especially for dissolution, varying continuously in composition from an ionically conducting rubber phase to an electronically conducting solid state PVC/graphite composite. The gradient part had a thickness of 200 microm. The electrodes life span exceeded 6 months. An ion exchange procedure was used to prepare them for one specific drug. This enabled us to use one universal electrode built to measure a wide array of drugs. The system parameters such as accuracy, reproducibility and linearity were presented with the data obtained for the drug dapoxetine. In dissolution, accurate measurements were possible from 10(-9) to 10(-3) M concentrations, for high log P drugs. The effect of t(90) response times on the measurement error was estimated. The t(90) response times of the electrodes were concentration dependent, and varied between 50 and 10 s for, respectively, 10(-6) and 10(-3) M concentrations. Potential drift was studied in detail. The measurements performed with these electrodes showed an accuracy of 1%, and inter- and intra electrode variabilities of 0.6 and 1.7%, respectively. The electrodes were successfully applied in colloidal media containing suspended matter, typically formed during dissolution of tablets. The advantages and pitfalls of potentiometry over the presently used techniques for dissolution testing are discussed.
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Affiliation(s)
- Hugo Bohets
- Antwerp University, Chemistry Department, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
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Vissers B, Bohets H, Everaert J, Cool P, Vansant E, Du Prez F, Kauffmann J, Nagels L. Characteristics of new composite- and classical potentiometric sensors for the determination of pharmaceutical drugs. Electrochim Acta 2006. [DOI: 10.1016/j.electacta.2006.03.040] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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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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Hassan SS, Elnemma EM, Mahmoud WH, Mohammed AH. Continuous potentiometric monitoring of viagra (sildenafil) in pharmaceutical preparations using novel membrane sensors. J APPL ELECTROCHEM 2005. [DOI: 10.1007/s10800-005-9041-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abourashed E, Abdel-Kader M, Habib AA. HPTLC determination of sildenafil in pharmaceutical products and aphrodisiac herbal preparations. JPC-J PLANAR CHROMAT 2005. [DOI: 10.1556/jpc.18.2005.5.7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Affiliation(s)
- R K Gilpin
- Brehm Research Laboratories, College of Science and Mathematics, Wright State University, Dayton, Ohio 45435, USA
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