Ammonium Reineckate Research Articles

Characteristics and electrochemical membrane sensors for selective study and determination of some antidepressant drugs in their pharmaceutical preparations

The construction and electrochemical characterisation of potentiometric sensors of the PVC-membrane type are described being developed for the determination of selected antidepressants; namely: Olanzapine, Oxazepam, and Lorazepam. The sensing PVC-membranes incorporate the ion-associates of the drug cations with ammonium reineckate as selective materials dispersed in 2-nitrophenyl-octylether (NPOE) or dibutyl sebacate (DBS) as the plasticizers of choice. These ISEs exhibit rapid, stable and nearly Nernstian response over a relatively wide concentration range of 1 ´ 10-7 M – 0.01 mol L-1 for Olanzapine and 1 ´ 10-6 – 0.01 mol L-1 for Oxazepam and Lorazepam, in mild acidic solutions with pH 4.5. No interferences caused by either inorganic or organic species were found. The three electrodes developed have been tested for potentiometric titrations of all three drugs, as well as for their direct determination via the respective calibration curves. The individual experiments then resulted in average recovery rates in an interval of 98.4-99.2 %, with the R.S.D. of ca. ±1.5 % (n = 3) for all three analytes of interest. Finally, the method proposed has been applied to the determination of the three drugs in pharmaceutical formulations and in urine, when the results obtained were comparable to those obtained with the reference HPLC measurements.

Ultrasensitive functionalized CeO2/ZnO nanocomposite sensor for determination of a prohibited narcotic in sports pethidine hydrochloride

The extraordinary features of cerium oxide (CeO2) and zinc oxide (ZnO) nanostructures have encouraged substantial attention to those nanocomposites as probable electroactive complexes for sensing and biosensing purposes. In this study, an advanced novel factionalized CeO2/ZnO nanocomposite-aluminum wire membrane sensor was designed to assess pethidine hydrochloride (PTD) in commercial injection samples. Pethidine-reineckate (PTD-RK) was formed by mixing pethidine hydrochloride and ammonium reineckate (ARK) in the presence of polymeric matrix (polyvinyl chloride) and o-nitrophenyl octyl ether as a fluidizing agent. The functionalized nanocomposite sensor displayed a fast dynamic response and wide linearity for the detection of PTD. It also revealed excellent selectivity and sensitivity, high accuracy, and precision for the determination and quantification of PTD when compared with the unmodified sensor PTD-RK. The guidelines of analytical methodology requirements were obeyed to improve the suitability and validity of the suggested potentiometric system according to several criteria. The developed potentiometric system was suitable for the determination of PTD in bulk powder and commercial products.

Selective Ion‐pair Potentiometric Sensor for the Determination of Ondansetron Hydrochloride in Different Matrixes

A facile, novel, and, sensitive potentiometric sensor has been developed to quantitatively determine ondansetron hydrochloride in bulk and pharmaceutical dosage forms. The sensor comprised an ion-pair between ondansetron hydrochloride and ammonium reineckate reagent, as an electrochemically active substance, on a polyvinyl chloride (PVC) matrix. Synthesis optimization was carried out by firstly altering the proportion of the ion-pair, PVC, and the plasticizer and subsequently, many plasticizer types have been investigated to realize the best performance. The optimum electrode consisted of 48.5 % polyvinyl chloride, 48.5 % dibutyl phthalate, and 3 % ionic pair complex and has shown a respectful Nernstian relationship within a linear range of (5.06×10−6–2592.92×10−6 M) and a slope of 57.277 mV×decade−1 in response to the drug. The electrode worked perfectly in a pH range of (1.9–6.1) where the analyte kept dissolved. Interestingly, the electrode demonstrated a fast response time of 30 sec, a lower limit of detection of 4.83×10−6 M, and an electrode lifetime of up to 30 days. The prepared electrode was applied successfully to determine the drug in its pharmaceutical dosage forms and the method validity was established. Hence, the electrode might be applied easily for the routine analysis of ondansetron hydrochloride in both scientific labs and drug industry.

Comparative study of four innovative earth-friendly platforms for rapid analysis of daclatasvir dihydrochloride: Application on different matrices

BackgroundDaclatasvir dihydrochloride has important roles not only in the management of COVID-19 pandemic symptoms but also in the treatment of chronic hepatitis C infection.ObjectiveThe current research presents four novel and simple platforms including silver-nanoparticles spectrophotometric technique and three electrochemical conductometric ones for daclatasvir analysis in its tablet, biological fluids, and dissolution media.MethodsThe spectrophotometric platform involved the synthesis of silvernanoparticles through a redox reaction between the reducing agent (daclatasvir) and the oxidizing agent (silver nitrate) in presence of polyvinylpyrrolidone as a stabilizing agent. The produced silver-nanoparticles have an intense surface plasmon resonance peak at 421 nm where the measured absorbance values were utilized for quantitative spectrophotometric determination of daclatasvir. While the electrochemical conductometric platforms involved the reaction of daclatasvir with three different precipitating reagents (silver nitrate, phosphomolybdic acid, and ammonium reineckate) to form ion associates between these reagents and daclatasvir in the aqueous system.ResultsAll proposed platforms were validated in line with recommendations of the international conference on harmonization producing satisfactory outcomes within the agreed boundaries.ConclusionThe proposed platforms are green alternatives for routine rapid assay of daclatasvir at the cheapest cost because their results were observed to be nearly similar to those of the reported platform. Moreover, the suggested spectrophotometric platform’s sensitivity can be employed for investigating daclatasvir bioequivalence.

Determination of moxifloxacin hydrochloride in AVELOX pharmacological formulations using modified potentiometer sensors

Three different carbon paste (CP), silk-screen (SP) and poly (vinyl chloride) (PVC) modified electrodes were obtained to verify the reliability of AVELOX, the generic name of which is Moxifloxacin HCl (AV-MOXH). The sensing membranes were containing AVELOX ion associated complexes with sodium tetraphenylborate (NaTPB), phosphomolybdic acid (PMA), phosphotungstic acid (PTA), and ammonium reineckate (RN) as electroactive materials. All three electrodes gave fast, viable, and near-Nernstian linear responses over a relative wide concentration range that ranged from 1.010-6 to 1.010-2 mol / L AV-MOXH at 25° C with a monovalent cationic decrease. The sensors demonstrated a good discernment of AV-MOXH from numerous inorganic and organic compounds such as glucose, sucrose, Na+, Ca+, etc. Additionally, the isothermal coefficients along with selectivity coefficients were calculated. The modified Screen Printed Electrode sensor appeared to be highly sensitive for the determination of AV-MOXH. The electrode response was observed in pH range 2--6 for ISPE electrodes and IPVC electrodes and 3--7 for ICPE electrodes under various temperature conditions. The short response time, lifetime validity, recovery, and all the methods of validation such as limit of detection and limit of quantification were estimated. The potentiometric method turned out to be suitable for determining AV-MOXH in pharmacological formulations, and the findings obtained are comparable to the “HPLC official method” in terms of the agreement. As a result, the postulated potentiometric approach was verified in accordance with IUPAC guidelines.

Selective Consecutive Determination of Desloratadine and Montelukast Sodium in Their Pure and Binary Dosage Form Based on Pencil Graphite Electrochemical Sensors.

In this study, we present a new, green electrochemical method for potentiometric estimation of desloratadine and montelukast sodium in their pure and binary dosage form. For that, three pencil graphite sensors were fabricated; the first one was prepared to analyse desloratadine drug (DES) by coating the graphite bar with the coating membrane, which comprises the ion pair of desloratadine and ammonium reineckate reagent (RNK), the polymer poly vinyl chloride (PVC), and the plasticizers dibutyl phthalate (DBP). The second one, which was used to analyse montelukast (MON), was constructed by using the ion pair of cadmium chloride reagent (Cd.) with montelukast and the same earlier named polymer and plasticizer. As a trial to analyse both of the drugs by the same sensor consecutively, we have constructed a combined pencil graphite electrode, which contains the two earlier suggested ion pairs, that is, we can use this electrode to selectively analyse for each drug. The proposed electrodes were effectively used for analysis of DES and MON as a single dosage form and as combined pharmaceutical preparation, without any need for prior separation that was performed depending on the difference in the efficient pH range for each sensor. The proposed sensors exhibited a Nernstian equation slopes of −30.11, 27.70, (−29.16, 29.79) mv. decade−1 in the linearity range 5.00 × 10−5−1.00 × 10−2 and 1.00 × 10−5 − 1.00 × 10−2 M, respectively. The sensors exhibit high sensitivity according to LOD values ((0.036–0.018) − (0.025-0.026) µM), respectively, and important selectivity toward the studied drugs in presence of interfering ions and excipients. The optimum circumstances were studied, and the method was validated by application of ICH rules. Finally, the method was compared with a documented method, and the required statistical values were calculated.

Optimized ion selective electrode for determination of Tamsulosin hydrochloride in the presence of co-formulated Deflazacort in bulk, tablet dosage form and human urine

Direct analytical methods offer an excellent tool for rapid determination of pharmaceuticals without deviation from the green analytical chemistry principles. In this work, a potentiometric ion selective electrode (ISE) method for the selective determination of the α1A-adrenoceptor blocker, Tamsulosin HCl was developed, optimized and assessed for greenness. Six different PVC-membrane sensors were fabricated using 2-nitrophenyl octyl ether (NPOE) as a plasticizer. Three ion exchangers were used, namely sodium tetraphenyl borate (Na.TPB), sodium tetrakis- [3,5-bis (trifluoro- methyl) phenyl] borate (Na.Tetrakis) and ammonium reineckate (Amm. RK) in exchange with the two ionophores, 4-tert-Butylcalix [8] arene (Calix.) and 2-hydroxypropyl-β-cyclodextrin (β-CD). The electrochemical responses of all sensors were studied and recorded. The sensor which consisted of sodium tetraphenyl borate as ion exchanger and 4-tert-Butylcalix [8] arene as ionophore was selected for application to analysis of Tamsulosin HCl in dosage form and human urine. The electrochemical performance characteristics of the electrode were validated as per IUPAC recommendations. Analytical Eco Scale assessment was used for evaluation of the greenness of the method and compared with the USP official method for the determination of Tamsulosin HCl.

Determination of AVELOX (Moxifloxacin Hydrochloride) Tablets In Dosage Forms Modified With Potentiometer Sensors: A Comparative Analysis

Electro-chemical sensors response characteristics of three different electrodes modified with carbon paste (CP), screen printed (SC) and Poly-vinyl chloride(PVC) were fabricated to verify the credibility of drug “AVELOX”, whose generic name is “Moxifloxacin HCl” (AV-MOXH) are traced and calculated. The sensing membranes contain AVELOX (Moxifloxacin HCL) ion association complexes with “sodium tetraphenyl borate” (NaTPB), “Phosphomolybdic acid” (PMA), and “Phosphotungstic acid” (PTA) and “Ammonium Reineckate” (RN) as electro-active materials. All the three electrodes (ICPE, IPVC and ISPE) are subjected to underneath study displays fast, viable and near-Nernstian linear responses above a relative wide-ranging concentration which varies from (1.0×10-6)molL-1 to (1.0×10-2)molL-1 of AV-MOXH at 25°C along with a mono-valent cationic slope. On the basis of calculations and presented data in the paper shows that that the IPVCs modified electrodes, have slope values measured with 7.5mg are (53.2 ± 1.5),(58.2 ± 3.9) and (51.6 ± 2.0) mV decade -1 for NaTPB, PMA and PTA ion pairing reagents respectively. For ISPE modified electrode, the observed slope values are (59.7 ± 2.0) mV decade -1 with 22mg for NaTPB ion pair, (60.1 ± 2.0)mV decade -1 with 16mg for RN ion pair and (58.9 ± 3.2)mV decade -1 with 30 mg for PTA ion pair. Whereas, the obtained value of ICPE electrode altered with 7.5mg NaTPB shows slope calculated at (58.0 ± 2.0)mV decade -1 . The sensors demonstrate good discernment of Av-MOXH from numerous inorganic and organic compounds such as glucose, sucrose, Na+, Ca+,etc. Additionally, the isothermal coefficients along by selectivity coefficients is diagnosed. The modified Screen Printed Electrode sensor appears to be highly sensitive for determination of AV-MOXH. Electrode response was set up to observe their pH dependence range (2-6) for ISPEs and IPVC electrodes and (3-7) pH range for ICPE electrode with varied range of temperature. The short response time, life time validity, recovery and all the method of validation such limit of detection and limit of quantification are estimated. This potentiometric method is suitable for determining AV-MOXH in pharmacological formulations, and the findings obtained are comparable to the “HPLC official method” in terms of agreement. As a result, the postulated potentiometric approach was verified in accordance with IUPAC guidelines.

Novel and selective potentiometric sensors for Cinchocaine HCl determination in its pure and Co-formulated dosage form: A comparative study of in situ carbon sensors based on different ion pairing agents

Promising in situ carbon paste electrodes (ICPEs) have been fabricated for selective cinchocaine HCl (CIN.HCl) determination in its pure form and as co-formulated with other drugs in its pharmaceutical preparation (Otal). The fabricated ICPEs were modified with various ion pairing agents as sodium tetraphenylborate (NaTPB), phosphotungstic acid (PTA), phosphomolybdic acid (PMA) and ammonium reineckate (RN) as an electroactive material. A comparative study of the established ICPEs based on 6 mg PMA (electrode I), 6 mg PTA (electrode II) and 9 mg RN (electrode III) ion pairing agents was conducted with considering the optimization of the developed sensors performance characteristics. The developed sensors I, II and III exhibited a fast and linear response for the monovalent CIN.HCl drug over the spacious concentration range from 1.0 × 10–5 to 1.0 × 10–2 mol L-1 achieving superior Nernstian slope values of 59.80 ± 0.14, 59.20 ± 0.10 and 59.20 ± 0.24 mV decade-1, respectively, reflecting no deviation from the Nernstian behavior over the pH range of 2.5–7. The aforementioned sensors displayed a good distinguishing power for CIN.HCl over the other cations, sugars and other co-formulated drugs. Additionally, validation parameters have been studied according to the IUPAC recommendations. The proposed electrodes have been employed with a promising success for determining CIN.HCl in Otal (ear drop) with good relative standard deviation values. Moreover, the inter- and intra-day accuracy (expressed as recovery %) and precision (expressed as relative standard deviation %) of the established CIN.HCl selective potentiometric method have been studied. As, the inter-day accuracy and precision ranges were found to be 99.46–100.1, 99.59–99.90 and 99.58–100.3% and 0.315–0.844, 0.263–1.199 and 0.328–0.703% while the intra-day accuracy and precision ranges were 99.62–101.4, 99.59–100.5 and 99.71–100.5% and 0.263–1.220, 0.471–0.877 and 0.528–0.885% for the established sensors I, II and III in the CIN.HCl pharmaceutical form (Otal), respectively.

Potentiometric determination of oxybutynin hydrochloride in pharmaceutical formulations at modified carbon paste electrodes

A new potentiometric sensitive and selective modified carbon paste (MCPE) electrodes based on phosphotungestic acid (PTA), sodium tetraphenyl borate (NaTPB), phosphomolybdic acid (PMA) or ammonium reineckate (RN) ion pairing agents for determination of (Ox.HCl) were developed. The proposed electrodes have a Nernstian slope values of 58.50±0.71, 58.71±1.20, 54.80±1.30 and 59.20±0.70 mV decade-1for electrodes modified with 20, 10, 5 and 10 mg of Ox-TPB (electrode I), Ox-RN (electrode II), Ox-PMA (electrode III) and Ox-PTA (electrode IV) ion pairs, respectively, with a dynamic drug concentration range at 25 (C was 1.0x10-5 - 1.0x10-2 mole L-1 with detection limit of 1.0× 10-5 mol L-1. The response of MCPEs were pH independent in the range 2.0-6.0 with a fast response time of 10 s for electrode I and 12 s for electrodes II-IV. The MCPEs showed a relatively long life time of 36 days. A pure and pharmaceutical formulation of Ox.HCl was quantified using calibration and standard addition methods and the obtained results agreed with that of the official HPLC method. Validation parameters were optimized according to ICH recommendations.

Spectrophotometric and atomic absorption spectrometric determination of cephalexin and cephradine in dosage forms

This paper describes two simple, sensitive and selective spectrophotometric and atomic absorption spectrometric (AAS) procedures for the determination of two compounds of cephalosporins (Cephalexin monohydrate and Cephradine). These procedures are based on the formation of ion-pair complexes between the drugs and ammonium reineckate. The formed precipitates are quantitatively determined either spectrophotometrically or by AAS procedures. The methods consist of reacting drugs with Reinecke's salt in an acidic medium at a temperature of 25 ± 2°C. The spectrophotometric procedure (procedure I) is based on dissolving the formed precipitate with acetone. The volume was completed quantitatively and absorbance of the solution was measured at 525 nm against blank. Also, the AAS procedures (procedure II) are quantitatively determined directly or indirectly through the chromium precipitate formed or the residual unreacted chromium in the filtrate at 358.6 nm. The optimum conditions for precipitation have been carefully studied. Beer's law is observed for the studied drugs in the ranges 0.1-1.5 mg mL-1 or 5-70 μg mL-1 using spectrophotometric or AAS methods, with correlation coefficients ≥ 0.9965, respectively. Both procedures I and II were accurate and precise when applied to the analysis of the cited cephalosporins in different dosage forms with good recovery percent ranged from 98.90 ± 0.94 to 100.15 ± 0.97 without interference from additives.

Electrochemical Quantitative Assessment of Labetalol Hydrochloride in Pure Form and Combined Pharmaceutical Formulations

This work describes how to utilize the electrochemical technique to determine labetalol hydrochloride (Lab) in pure form and combined pharmaceutical formulation for quality control purposes. Four membrane sensors were developed using two plasticizers, dioctyl phthalate with 2-hydroxypropyl-?-cyclodextrin and ammonium reineckate (RNC) for sensors 1a and 2a, and tributyl phthalate with 2-hydroxypropyl-?-cyclodextrin and ammonium reineckate for sensors 1b and 2b as ionophores in polyvinyl chloride (PVC) matrix. Fast response and stable Nernstian slopes of 59.60, 57.58, 53.00 and 55.00 mV/decade for sensors 1a, 2a, 1b, and 2b, respectively, were obtained by developed sensors within a concentration range 10-4 M-10-2 M over pH range 2.00-5.10. Developed sensors showed good selectivity for Lab in pure form, in the presence of co-administered drugs, many of interfering ions, and excipients present in pharmaceutical formulation. No remarkable difference was detected upon the statistical comparison between the results of proposed sensors and the official method.

A comparative study of tetra-n-butylammonium bromide potentiometric selective screen printed, carbon paste and carbon nanotube modified graphite sensors

A comparative study between in situ screen printed (SPE), carbon paste (CPE) and carbon nanotube modified graphite (CNTME) electrodes was established for the determination of tetra-n-butylammonium bromide (TBAB) in pure and spiked tap water samples. Different experimental conditions as ion-pairing agent type and content, carbon nanotube content, plasticizer, response and soaking time, pH and, temperature effects were studied. The in situ SPEs commingling 6 mg sodium tetraphenylborate (NaTPB, electrode I), 6 mg phosphotungstic acid (PTA, electrode II), 6 mg phosphomolybdic acid (PMA, electrode III), and 12 mg ammonium reineckate (RN, electrode IV) ion-pairing agents displayed the best Nernstian slope values of 60.71 ± 1.94, 59.75 ± 0.38, 59.73 ± 0.76 and 59.90 ± 0.51 mV decade−1 over a perceptible spacious concentration range from 1.0 × 10−5 to 1.0 × 10−2 mol L−1, respectively. While it was observed that the in situ CPE containing 9 mg of RN ion-pairing agent (electrode V) presenting Nernstian slope of 60.38 ± 0.16 mV decade−1 over concentration range from 1.0 × 10−5 to 1.0 × 10−2 mol L−1 and in order to improve the efficiency of electrode V, the paste was modified with different amounts of carbon nanotube and the best content was found to be 100 mg of carbon nanotube (electrode VI) with Nernstian slope of 59.90 ± 0.45 mV decade−1 over a broader concentration range from 1.0 × 10−6 to 1.0 × 10−2 mol L−1. The fabricated sensors exhibited fast response time with a relatively low isothermal coefficient. The analytical performance of the SPEs, CPE, and CNTME compared with respect to distinguishing power for TBAB relative to a number of potential interfering cations were investigated. The obtained results were satisfactory with excellent detection and quantification limit, recovery, and relative standard deviation percentages values which indicate the precision and accuracy of the established sensors.

Electrochemical performance of screen printed sensors for potentiometric determination of anticholinergic oxybutynine hydrochloride in pharmaceutical formulations and biological fluids.

New potentiometric sensitive and selective modified screen printed electrodes (MSPE) which based on phosphotungestic acid (PTA), sodium tetraphenyl borate (NaTPB), phosphomolybdic acid (PMA) or ammonium reineckate (RN) ion pairing agents for determination of oxybutynine hydrochloride (OBCH) were developed. The proposed electrodes have Nernstian slope values of 59.20±0.52, 58.00±0.22 and 58.52±0.22 mV decade-1 for electrodes modified with 7.5, 17.5 and 7.5 mg of RN (electrode I), NaTPB (electrode II) and PTA (electrode III) ion pairing agents, respectively. It is found that the dynamic drug concentration range at 25 (C was 1.0x10-5 - 1.0x10-2 mole L-1 with detection limit (LOD) equal 1.0× 10-5 mol L-1 and limit of quantification (LOQ) equal 3.33×10-5 mol L-1. The response of MSPEs was pH independent in the range 2.0-6.0. The investigated electrodes have fast response time of 10, 9 and 8 s for electrodes I, II and III, respectively. These electrodes have good Nernstian response in the temperature range 10–60 °C. The slope of the straight–line obtained represented the isothermal coefficient of MSPEs which were found to be 1.594 ×10-3, 2.151×10-3 and 2.377×10-3 V/ for electrodes I, II and III, respectively. The small values of the isothermal coefficient indicated the high thermal stability of the electrodes. The MSPEs showed a relatively long life time of 36 days. Pure, biological fluids and pharmaceutical formulation of OBCH were quantified using calibration and standard addition methods and the obtained results agreed with that of the official HPLC method. Validation parameters were optimized according to ICH recommendations.

A green stability indicating ISE-potentiometric method for the monitoring of chlorhexidine in the presence of its rapidly absorbed toxic degradation product; a kinetic study

Chlorhexidine (CHX) is an antiseptic and disinfectant used in several antimicrobial preparations. In the current study an environmentally friendly ISE-potentiometric method was developed for the determination of CHX, measurements were carried out directly in the aqueous solution of the sample without pretreatment. Four PVC-membranes were fabricated using dioctylphthalate as a solvent mediator along with different cation exchangers, namely; sodium tetraphenylborate, sodium phosphotungstate tribasic, sodium phosphomolybdate and ammonium reineckate. Responses were compared and that containing ammonium reineckate illustrated the best near-Nernstian slope through a wide linear range (3.85 × 10−6–1 × 10−3 M). The sensor was able to determine CHX in colored and turbid solutions without prior extraction, pretreatment, filtration or derivatization steps. This method enabled in-site stability study without interference of para-chloroaniline (PCA) the most common and carcinogenic degradation product by monitoring the degradation kinetics of CHX at different pH values (3.5, 4.0 and 5.0). The sensor was able to provide a reliable in-line monitoring of the process without the need for frequent sample withdrawal at time intervals or sample pretreatment steps which saved time. Sensor response characteristics were calculated according to the IUPAC recommendations and the method was validated as per the ICH recommendations. The proposed method provided a green eco-friendly method that saves cost, time and effort, and consumes the least amount of chemicals.

Determination of Lomefloxacin Hydrochloride by Ion-pair Complex Formation with Ammonium Reineckate Using Atomic Absorption Spectrometry

Determination of Lomefloxacin Hydrochloride by Ion-pair Complex Formation with Ammonium Reineckate Using Atomic Absorption Spectrometry

Conductometric Titration for Determination of Trazodone Hydrochloride and Solubility Products of its Ion-Associated Complex Species

Objective: Conductometric determination of trazodone hydrochloride, with two precipitating reagents; Ammonium Reineckate and sodium tetraphenylborate has been investigated.Methods: The formed ion-associates were studied conductomterically for the determination of solubility products and other functions associated with the process of precipitating trazodone hydrochloride were determined. Moreover, two new maneuvers towards equivalence point detection were carried out. In this study, data processing was performed using numerical derivatization (second derivative) and Boltzmann algorithm. Results: Although, the described procedures allowed the determination of trazodone hydrochloride within the range of 2-14 mg using both reagents has less sensitivity other than reported method but has more advantages in simplicity, low cost , relatively short analysis time and direct analysis with good recoveries between 100.01% and 100.07% with relative standard deviation less than 2%. Conclusion: These methods were validated and successfully applied for the determination of trazodone hydrochloride in Trittico® tablets. The obtained results were statistically compared with those of the official method by applying t-test and F-value at 95% confidence level and no significant difference was observed regarding accuracy and precision.

Preparation and characterization of in situ carbon paste and screen-printed potentiometric sensors for determination of econazole nitrate: surface analysis using SEM and EDX

The construction and performance characteristics of new sensitive and selective in situ carbon paste (ICPE) and screen-printed (ISPE) potentiometric sensors modified with ion-pairing agents such as phosphotungstic acid, sodium tetraphenylborate, phosphomolybdic acid and ammonium reineckate for determination of econazole nitrate (ECN) have been developed. The reaction mechanism between ECN and ion-pairing agents at the electrode surface was studied through scanning electron microscope and energy-dispersive X-ray analysis. The electrodes under investigation showed potentiometric response for ECN in the concentration range from 1.0 × 10−6 to 5.0 × 10−3 mol L−1 and from 1.0 × 10−6 to 1.0 × 10−2 mol L−1 for ISPE (electrode I) and ICPE (electrode II) potentiometric sensors, respectively, at 25 °C. The electrode response was pH independent in the range 2.5–7.5 and 2.5–6.5 for electrodes I and II, respectively. These sensors have Nernstian slope values of 59.4 ± 0.2 and 59.10 ± 0.2 mV decade−1 with detection limit of 1.0 × 10−6 mol L−1 for electrodes I and II, respectively. The electrodes showed fast response time of 4 and 9 s for electrodes I and II, respectively. The ISPE (electrode I) showed lifetime of 28 days, and this was considered as advantage over ICPE (electrode II). Selectivity for ECN with respect to a number of interfering materials was also investigated. The proposed electrodes were applied for determination of ECN in pure and pharmaceutical formulation using calibration, potentiometric titration and standard addition methods. The results showed good agreement with those obtained using official method. The t and F values indicated no significant difference between the suggested and reported methods. Method validation parameters were optimized according to ICH recommendations.

Novel potentiometric sensors for pyrilamine maleate

The fabrication and electrochemical response characteristics of four novel potentiometric sensors for determination of pyrilamine maleate (PyraH) were described. The sensors include polymeric membrane electrodes (PME1, PME2) and carbon paste electrodes (CPE1, CPE2). The fabricated sensors were based on the ion-pair of pyrilamine with sodium tetraphenylborate (NaTPB) and ammonium reineckate (NH4RN) using dibutyl phthalate (DBP) as plasticizing solvent. The sensors showed linear, stable and near-Nernstian slopes of 56.4 ± 0.4, 54.2 ± 0.2, 58.8 ± 0.3 and 57.9 ± 0.4 mV decade−1 at 25 ± 0.1 °C and detection limits of 2.0 × 10−5, 1.8 × 10−5, 1.0 × 10−5 and 9.5 × 10−6 mol L−1 for PME1, PME2, CPE1 and CPE2 sensors, respectively. The response time was less than 10 and 8 s for polymeric membrane and carbon paste sensors. The proposed sensors displayed good selectivity for pyrilamine with respect to a number of common inorganic and organic species. The thermal temperature coefficients of the investigated sensors were 0.9508, 0.7012, 0.9450 and 0.6497 mV °C−1. Modified carbon paste sensors showed lower detection limits, higher thermal stability and faster response time than those of polymeric membrane sensors. The proposed sensors displayed useful analytical characteristics for determination of pyrilamine in pharmaceutical preparation and biological fluids (Human urine and plasma).

A New method for ISE construction for methyl orange dyes and using for indirect determination of Amitriptyline Hydrochloried drug

A new method for construction ion-selective electrode (ISE) by heating reaction of methyl orange with ammonium reineckate using PVC as plasticizer for determination methyl orange and determination Amitriptyline Hydrochloried drug by formation ion-pair on electrode surface . The characteristics of the electrode and it response as following : internal solution 10-4M , pH (2.5-5) ,temperature (20-30) and response time 2 sec. Calibration response for methyl orange over the concentrationrange 10-3 -10-9 M with R=0.9989 , RSD%=0.1052, D.O.L=0.315X10-9 MEre%=(-0.877- -2.76) , Rec%.=(97.230 -101.711) .