Microsized Graphite Sensors for Potentiometric Determination of Cyclobenzaprine Hydrochloride in Pure Powder, Tablets, and Plasma

2011 ◽  
Vol 94 (6) ◽  
pp. 1807-1814 ◽  
Author(s):  
Nesrin K Ramadan ◽  
Hala E Zaazaa ◽  
Hanan A Merey
Keyword(s):  
Polyvinyl Chloride ◽  
International Union ◽  
Electroactive Material ◽  
Significant Difference ◽  
Intact Drug ◽  
Sensitivity And Selectivity ◽  
Ph Range ◽  
The U.S ◽  
Chloride Matrix

Abstract Two cyclobenzaprine hydrochloride (CZ) microsized graphite selective sensors were investigated with dibutylsebacate as a plasticizer in a polymeric matrix of carboxylated polyvinyl chloride (PVC-COOH) in the case of sensor 1, based on the interaction between the drug and the dissociated COOH groups in the PVC-COOH. Sensor 2 was based on the interaction between the drug and ammonium reineckate, which acted as anionic electroactive material in the presence of polyvinyl chloride matrix. The two sensors were constructed by using 2-hydroxy propyl β-cyclodextrin as an ionophore, which has a significant influence on increasing the membrane sensitivity and selectivity of both sensors. Fast and stable Nernstian responses of 1 × 10–5–1 × 10–2 and 1 × 10m–4–1 × 10–2 M for the two sensors, respectively, with slopes of 58.6 and 55.5 mV/decade, respectively, over the pH range 2–4 were obtained. The proposed method displayed useful analytical characteristics for determination of CZ in its pure powder form with average recoveries 99.95 ± 0.23 and 99.61 ± 0.34% for sensors 1 and 2, respectively, and in plasma with good recoveries. The sensors were also used to determine the intact drug in the presence of its degradate and, thus, could be used as stability-indicating methods. The obtained results by the proposed methods were statistically analyzed and compared with those obtained by the U.S. Pharmacopeia method; no significant difference for either accuracy or precision was observed. Results obtained with the two electrodes revealed their performance characteristics, which were evaluated according to International Union of Pure and Applied Chemistry recommendations.

scholarly journals Membrane Electrodes for the Determination of Pyridostigmine Bromide

2009 ◽  
Vol 92 (6) ◽  
pp. 1631-1638 ◽  
Author(s):  
Amira M El-Kosasy ◽  
Maissa Y Salem ◽  
Mohamed G El-Bardicy ◽  
Mohamed K Abd El-Rahman
Keyword(s):  
Pyridostigmine Bromide ◽  
Membrane Electrodes ◽  
Anionic Site ◽  
Nitrophenyl Octyl Ether ◽  
Significant Difference ◽  
Intact Drug ◽  
Sensitivity And Selectivity ◽  
Ph Range ◽  
Drug Solution

Abstract Two pyridostigmine bromide (PB) selective electrodes were investigated with 2-nitrophenyl octyl ether as a plasticizer in a polymeric matrix of carboxylated polyvinyl chloride (PVC-COOH), based on the interaction between the drug solution and the dissociated COOH groups in the PVC-COOH. One of the sensors was fabricated by using PVC-COOH only as anionic site without incorporation of an ionophore (sensor 1). The second sensor was constructed by using 2-hydroxy propyl -cyclodextrin as an ionophore (sensor 2). Linear responses of PB within a concentration range of 103102 and 105102 M, with slopes of 51.9 0.31 and 56.7 0.40 mV/decade over pH range of 510 were obtained using sensors 2 and 1, respectively. The proposed method displayed useful analytical characteristics for determination of PB in tablets with average recoveries of 100.22 0.62, and 100.15 0.72, and in plasma with average recoveries of 99.14 1.19 and 99.79 0.72, for sensors 2 and 1, respectively. The utility of 2-hydroxy propyl -cyclodextrin as an ionophore has a significant influence on increasing both membrane sensitivity and selectivity of sensor 2 in comparison with sensor 1. The methods were also used to determine the intact drug in the presence of its degradate, and thus could be used as stability-indicating methods. The results obtained by the proposed procedures were statistically analyzed and compared with those obtained by the U.S. Pharmacopeia method. No significant difference for either accuracy or precision was observed.

scholarly journals Membrane Electrodes for Determination of Some -Blocker Drugs

2007 ◽  
Vol 90 (4) ◽  
pp. 987-994 ◽  
Author(s):  
Nesrin K Ramadan ◽  
Hala E Zaazaa
Keyword(s):  
Pharmaceutical Formulations ◽  
Official Method ◽  
Membrane Electrodes ◽  
Timolol Maleate ◽  
Electroactive Material ◽  
Poly Vinyl Chloride ◽  
Significant Difference ◽  
Ph Range ◽  
Quality Assurance Standards

Abstract Five poly(vinyl chloride) (PVC) matrix membrane electrodes responsive to the -blockers atenolol (AT), bisoprolol fumarate (BI), timolol maleate (TI), and levobunolol HCl (LV) were developed and characterized. A precipitation-based technique with ammonium reineckate anion as an electroactive material in PVC matrix with AT, BI, TI, and LV cations was used for fabrication of Electrodes 14, respectively. Electrode 5 fabrication was based on precipitation of LV cation with tungstophosphate anion as an electroactive material. Fast and stable Nernstian responses at 1 1021 107 M for different -blockers over the pH range of 28 were found for these electrodes, which were evaluated according to International Union of Pure and Applied Chemistry recommendations. The method was successively applied for the determination of -blockers in their pharmaceutical formulations. Validation of the method according to quality assurance standards showed the suitability of the proposed electrodes for use in the quality control assessment of these drugs. The recoveries for the determination of the -blocker drugs by the 5 proposed selective electrodes were 100.1 0.7, 99.9 0.8, 100.0 1.1, 100.5 1.1, and 100.6 0.7% for Sensors 15, respectively. Statistical comparison between the results obtained by this method and the official method of the drugs was performed and no significant difference was found.

scholarly journals Polymeric Matrix Membrane Sensors for Stability-Indicating Potentiometric Determination of Oxybutynin Hydrochloride and Flavoxate Hydrochloride Urogenital System Drugs

2008 ◽  
Vol 91 (6) ◽  
pp. 1318-1330 ◽  
Author(s):  
Mohamed Heba ◽  
Nesrin Ramadan ◽  
Moustafa El-Laithy
Keyword(s):  
Degradation Products ◽  
Pharmaceutical Formulations ◽  
Official Method ◽  
Urogenital System ◽  
Electroactive Materials ◽  
Significant Difference ◽  
Ph Range ◽  
Oxybutynin Hydrochloride ◽  
Flavoxate Hydrochloride

Abstract Four polyvinyl chloride (PVC) matrix membrane electrodes responsive to 2 drugs affecting the urogenital systemoxybutynin hydrochloride (OX) and flavoxate hydrochloride (FX)were developed, described, and characterized. A precipitation-based technique with tungstophosphate (TP) and ammonium reineckate (R) anions as electroactive materials in a PVC matrix with an OX cation was used for electrode 1 and 2 fabrication, respectively. Electrode 3 and 4 fabrication was based on use of the precipitation technique of FX cation with tetrakis (4-chlorophenyl) borate and R anions as electroactive materials. Fast and stable Nernstian responses in the range 1 1021 106 M for the 2 drugs over the pH range 58 revealed the performance characteristics of these electrodes, which were evaluated according to International Union of Pure and Applied Chemistry recommendations. The method was applied to FX and OX in their pharmaceutical formulations and in human plasma samples. The 4 proposed sensors were found to be specific for the drugs in the presence of up to 60 of their degradation products. Validation of the method according to the quality assurance standards showed suitability of the proposed electrodes for use in the quality control assessment of these drugs. The recoveries for determination of the drugs by the 4 proposed selective electrodes were 99.5 0.5, 100.0 0.4, 99.9 0.4, and 100.1 0.4 for sensors 14, respectively. Statistical comparison between the results obtained by this method and the official method of the drugs was done, and no significant difference found.

New Liquid Membrane Electrode for Determination of Lidocaine in Local Anesthetic Formulations

1986 ◽  
Vol 69 (4) ◽  
pp. 618-620
Author(s):  
Saad S M Hassan ◽  
Mona A Ahmed
Keyword(s):  
Local Anesthetic ◽  
Liquid Membrane ◽  
Pharmaceutical Preparations ◽  
Ion Pair ◽  
Membrane Electrode ◽  
Lidocaine Concentration ◽  
Ph Range ◽  
Liquid Membrane Electrode ◽  
The U.S

Abstract A new lidocaine-responsive liquid membrane electrode based on the use of the lidocaine reineckate ion pair complex in nitrobenzene solvent has been developed. The electrode displays a linear response for 10-2-10-5M lidocaine over the pH range of 3-6.5. The response time varies from 35 s to 1 min depending on the lidocaine concentration. The life span of the electrode is at least 1 month. Excipients and diluents commonly used in local anesthetic formulations do not interfere. Determination of lidocaine in some pharmaceutical preparations gives results with an average recovery of 99% of the nominal values and a mean standard deviation of 1.7% which compare favorably with those obtained by the U.S. Pharmacopeia method.

scholarly journals Determination of Hydroxyurea in Capsules and Biological Fluids by Ion-Selective Potentiometry and Fluorimetry

2003 ◽  
Vol 86 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Amira M El-Kosasy
Keyword(s):  
Polyvinyl Chloride ◽  
Biological Fluids ◽  
Polymeric Matrix ◽  
Complex Method ◽  
Anionic Site ◽  
The Stability ◽  
The U.S ◽  
Mg Complexes

Abstract Two hydroxyurea selective electrodes were investigated with β-cyclodextrin used as ionophore and either tetrakis (p-chlorophenyl) borate (electrode 1), or tetrakis [3,4-bis (trifluoromethyl) phenyl] borate (electrode 2), as a fixed anionic site in a polymeric matrix of carboxylated polyvinyl chloride. Linear responses of hydroxyurea within a concentration range of 10−5–10−3M with slopes of 51.2 and 58.6 mV/decade with pH 3–6 were obtained by using electrodes 1 and 2, respectively. Two spectrofluorimetric methods involving the formation of drug–Al(III) complex (method 3) and drug–Mg(II) complex (method 4) at pH 5 were also investigated. These complexes emit fluorescence at wavelengths of 380 and 355 nm, after excitation at 305 nm, for Al and Mg complexes, respectively. The calibration graphs were rectilinear from 0.5 to 2.5 μg/mL for the Al complex and 1 to 5 μg/mL for the Mg complex. The 4 proposed methods display useful analytical characteristics for determination of hydroxyurea, with average recoveries of 100.2 ± 0.83 and 99.4 ± 1.81% in capsules and 99.7 ± 0.70 and 99.4 ± 1.25% in biological fluids for the potentiometric and fluorimetric methods, respectively. Results obtained by the proposed procedures were statistically analyzed and compared with those obtained by the U.S. Pharmacopeial method. The 4 proposed procedures were also used to determine the stability of the drug in the presence of its degradate, hydroxylamine.

Potentiometric Determination of Trace Amounts of Aluminium Utilizing Polyvinyl Chloride Membrane and Coated Platinum Sensors Based on E-N′-(2-Hydroxy-3-methoxybenzylidene) benzohydrazide

2013 ◽  
Vol 96 (1) ◽  
pp. 204-211 ◽  
Author(s):  
Somayeh Tajik ◽  
Mohammad Ali Taher ◽  
Iran Sheikhshoaie
Keyword(s):  
Polyvinyl Chloride ◽  
Tap Water ◽  
Direct Determination ◽  
Ion Concentration ◽  
Nonaqueous Media ◽  
Wide Range ◽  
And Performance ◽  
Ph Range ◽  
Polyvinyl Chloride Membrane

Abstract This paper describes the construction and performance characteristics of novel polyvinyl chloride membrane (PME) and coated platinum (CPtE) aluminium (Al) ion selective electrodes based on E-N′-(2-hydroxy-3-methoxybenzylidene) benzohydrazide. The electrodes exhibited linear responses with near Nernstian slopes of 19.9 ± 0.3 (PME) and 20.1 ± 0.4 (CPtE) mV/decade of activity within the Al3+ ion concentration range of 3.0 × 10–7 to 1.0 × 10–2 M for the PME and 1.0 × 10–7 –1.0 × 10–2 M for the CPtE. These sensors were applicable in a pH range of 3.0 to 7.0. The LODs of the PME and CPtE were 1.7 × 10–7 and 5.6 × 10–8 M, respectively. They had a response time of less than 10 s and could be used practically for a period of at least 2 months without measurable divergence in results. The isothermal temperature coefficient of the PME was 1.12 × 10–3 V/°C, and it can tolerate partially nonaqueous media up to 25%. The electrodes showed excellent selectivity towards Al3+ ions in the presence of a wide range of alkali, alkaline earth, and transition metals ions. They were successfully applied for the direct determination of Al3+ ions in tap water, aqueduct water, mineral water, and Al–Mg syrup and as indicator electrodes in potentiometric titration of Al ions with EDTA.

Polyvinyl Chloride Matrix Membrane Electrodes for Manual and Flow Injection Analysis of Chloroquine in Pharmaceutical Preparations

1991 ◽  
Vol 74 (6) ◽  
pp. 900-905 ◽  
Author(s):  
Saad S M Hassan ◽  
Mona A Ahmed
Keyword(s):  
Polyvinyl Chloride ◽  
Flow Injection ◽  
Flow Injection Analysis ◽  
Pharmaceutical Preparations ◽  
Membrane Electrodes ◽  
Direct Potentiometry ◽  
Potentiometric Response ◽  
Ph Range

Abstract Two types of polyvinyl chloride (PVC) matrix membrane electrodes responsive to the antimalarial drug chloroquine have been constructed, electrochemically evaluated, compared, and used in pharmaceutical analysis. Type 1 is the classic PVC model with chloroquine-tetraphenylborate (TPB) sensor; Type 2 is a coated silver disk without internal filling solution. Both electrode types exhibited rapid linear potentiometric response to the logarithmic concentration of diprotonated chloroquine cation in the 10−1–10−6M range with calibration slopes 28-30 mV/concentration decade over the pH range 1.8-6.2. These electrodes were sensitive enough to permit determination of chloroquine phosphate at concentrations as low as 5 μg/mL with good accuracy and precision. Determination of chloroquine in various pharmaceutical preparations using direct potentiometry and potentiometric titration with NaTPB gave an average recovery of 98.8% of the nominal values (SD 0.5%). The Type 2 electrode was also assessed in a flow-through sandwich cell for flow injection analysis. Results were compared with data obtained by the U.S. Pharmacopeia method.

Detection of Circulating Tissue Factor and Factor VII in a Normal Population

1996 ◽  
Vol 75 (05) ◽  
pp. 772-777 ◽  
Author(s):  
Sybille Albrecht ◽  
Matthias Kotzsch ◽  
Gabriele Siegert ◽  
Thomas Luther ◽  
Heinz Großmann ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Normal Population ◽  
Mean Value ◽  
Factor Vii ◽  
Significant Difference ◽  
Age Dependent ◽  
The Mean ◽  
Highly Correlated ◽  
And Gender

SummaryThe plasma tissue factor (TF) concentration was correlated to factor VII concentration (FVIIag) and factor VII activity (FVIIc) in 498 healthy volunteers ranging in age from 17 to 64 years. Immunoassays using monoclonal antibodies (mAbs) were developed for the determination of TF and FVIIag in plasma. The mAbs and the test systems were characterized. The mean value of the TF concentration was 172 ± 135 pg/ml. TF showed no age- and gender-related differences. For the total population, FVIIc, determined by a clotting test, was 110 ± 15% and the factor VIlag was 0.77 ± 0.19 μg/ml. FVII activity was significantly increased with age, whereas the concentration demonstrated no correlation to age in this population. FVII concentration is highly correlated with the activity as measured by clotting assay using rabbit thromboplastin. The ratio between FVIIc and FVIIag was not age-dependent, but demonstrated a significant difference between men and women. Between TF and FVII we could not detect a correlation.

Improvement Of Curvilinear Diagrams Of Concrete Deformation

2019 ◽  
pp. 99-104
Keyword(s):  
Reinforced Concrete ◽  
Peak Load ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Deformation Model ◽  
Reinforced Concrete Structures ◽  
Significant Difference ◽  
Deformation Diagrams

Problems when calculating reinforced concrete structures based on the concrete deformation under compression diagram, which is presented both in Russian and foreign regulatory documents on the design of concrete and reinforced concrete structures are considered. The correctness of their compliance for all classes of concrete remains very approximate, especially a significant difference occurs when using Euronorm due to the different shape and sizes of the samples. At present, there are no methodical recommendations for determining the ultimate relative deformations of concrete under axial compression and the construction of curvilinear deformation diagrams, which leads to limited experimental data and, as a result, does not make it possible to enter more detailed ultimate strain values into domestic standards. The results of experimental studies to determine the ultimate relative deformations of concrete under compression for different classes of concrete, which allowed to make analytical dependences for the evaluation of the ultimate relative deformations and description of curvilinear deformation diagrams, are presented. The article discusses various options for using the deformation model to assess the stress-strain state of the structure, it is concluded that it is necessary to use not only the finite values of the ultimate deformations, but also their intermediate values. This requires reliable diagrams "s–e” for all classes of concrete. The difficulties of measuring deformations in concrete subjected to peak load, corresponding to the prismatic strength, as well as main cracks that appeared under conditions of long-term step loading are highlighted. Variants of more accurate measurements are proposed. Development and implementation of the new standard GOST "Concretes. Methods for determination of complete diagrams" on the basis of the developed method for obtaining complete diagrams of concrete deformation under compression for the evaluation of ultimate deformability of concrete under compression are necessary.

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