Hosny Ibrahim

Potentiometric Flow Injection Analysis of Drotaverine Hydrochloride in Pharmaceutical Preparations

Abstract  Five poly (vinyl chloride) (PVC) membrane electrodes for the determination of drotaverine hydrochloride (DvCl) were constructed and fully characterized in terms of composition, life span, response time, usable pH range, working concentration range, and temperature. The membranes of these electrodes consist of drotaverinium‐silicotungstate (Dv‐ST), silicomolybdate (Dv‐SM), phosphotungstate (Dv‐PT), phosphomolybdate (Dv‐PM), or tetraphenylborate (Dv‐TPB) ion associations dispersed in PVC matrix with dibutyl phthalate plasticizer. The electrodes showed near‐Nernstian response over the concentration range of 2.0 × 10−6 to 1.0 × 10−2 M DvCl and were applied to the potentiometric determination of drotaverinium ion in pharmaceutical preparations in steady‐state and flow injection (FI) conditions with average recoveries of 98.1–102.2% and relative standard deviation of 0.308–1.310%. The electrodes exhibit good selectivity for DvCl with respect to a large number of inorganic cations, organic cations, sugars, and amino acids. The sensitivities of these electrodes are high enough to measure as low as 0.87 µg/mL of DvCl which permits the determination of the K sp values of the ion associates used.

New selenite ion-selective electrodes based on 5,10,15,20-tetrakis-(4-methoxyphenyl)-21H,23H-porphyrin-Co(II).

New polymeric membrane (PME), modified carbon paste (MCPE), and coated wire (CWE) selenite ion-selective electrodes based on 5,10,15,20-tetrakis-(4-methoxyphenyl)-21H,23H-porphyrin-Co(II) (CoTMeOPP) are reported. The best composition was the electrode containing 2% CoTMeOPP as the active material and 49% TCP as plasticizer. The electrodes reveal a Nernstian behavior over a concentration range of 5.5x10(-5) to 1.1x10(-2) M for PME, 5.2x10(-5) to 1.2x10(-2) M for MCPE and 1.2x10(-4) to 4.4x10(-3) M for CWE. The potentiometric response is pH dependent, since selenous acid is a diprotic acid. The slope of the selenite PVC electrode was -57.0 mV for the monovalent anion at pH 6.47, and -26.0 mV for the divalent anion at pH 11.00. The detection limits were 3.4x10(-5) and 4.7x10(-5) M at pH values 6.47 and 11.00, respectively. The electrodes manifest advantages of low resistance, very short response time (15 s), and most importantly good selectivities relative to a wide variety of other anions. In fact, the proposed selenite ion-selective electrodes show a great improvement compared to previously reported electrodes for selenite ion. The electrode was used for the determination of selenite in selenite/selenate mixture, in sodium selenite raw material powder, and in VitaFit Selenium ACE antioxidant tablets with recovery ranges of 90.0-103.3%.

Determination of lead in frying oils by direct current plasma atomic emission spectrometry

Two methods for determination of lead in frying oils by direct current plasma-atomic emission spectrometry were investigated. The first method is based on the formation of an oil-water emulsion followed by aspiration of the sample directly into the plasma. The second method involves extraction of lead from oil into an aqueous ethylene diamine tetraacetic acid phase before measurement. The methods were applied to the determination of lead in used frying oil samples collected from different parts of Cairo, Egypt.

Potentiometric determination of titanium(III), tin(II), and some hydrazine derivatives

Abstract A new potentiometric method had been used for the accurate determination of titanium(III), tin(II), isoniazid, nicotinic acid hydrazide, semicarbazide, 1,5-diphenylcarbazide, and p -hydrazinobenzoic acid by using alcoholic iodine solution as oxidant. A mercury(II) solution was used as titrant for the iodide produced and silver amalgam as the indicator electrode. The potential breaks were sharp and the methods were highly accurate.

Indirect atomic absorption and atomic emission spectrometric determination of antazoline, hydralazine and amiloride hydrochlorides and quinine sulphate

Ion-association complexes of antazoline HCl [I], hydralazine HCl [II], amiloride HCl [III] and quinine sulphate [IV] with [Co(SCN)4]2− and [Co(NO2)6]3− were precipitated and the excess unreacted cobalt complex was determined. A new method using atomic emission and atomic absorption spectrometry for the determination of the above drugs in pure solutions and pharmaceutical preparations is given. The drugs can be determined in the ranges 0.3–3.0, 0.19–1.96, 0.3–3.0, and 0.78–7.82 mg/25 ml solutions of I, II, III, and IV, respectively, with mean relative standard deviations of 0.65–2.03 % and recovery values of 95.76–101.2% indicating high precision and accuracy.

Atomic Emission Spectrometric Determination of Antazoline, Hydralazine, Amiloride, Thiamine and Quinine Based on Formation of Ion Associates with Ammonium Reineckate.

Abstract Ion-associate complexes of Antazoline HC1 (I), Hydralazine HC1 (II), Amiloride HC1 (III), Thiamine HC1 (IV) and Quinine sulphate (V) with ammonium reineckate were precipitated and their solubilities were studied as a function of pH, ionic strength and temperature. Saturated solutions of each ion-associate under the optimum precipitation conditions were prepared and the metal ion-content in the supernatent was determined. The solubility products were thus elucidated at different temperatures. A new accurate and precise method using direct coupled plasma-atomic emission spectrometry for the determination of the investigated drugs in pure solutions and in pharmaceutical preparations is described. The drugs can be determined by the present method in the ranges 0.3-3.0, 0.19-1.96, 0.3-3.0, 0.33-3.37 and 0.78-7.82 mg/25 ml solutions of I, II, III, IV and V, respectively.

Papaverine-Selective Plastic Membrane Electrode Based on Papaverinium Tetraphenylborate

Abstract A plasticized PVC membrane containing the lipophilic salt papaverinium-tetraphenylborate was used to construct an ion-selective electrode for papaverine hydrochloride (Pv+Cl−). The electrode shows near Nernstian response over the concentration range 1.6 × 10−5 1.3C × 10−2M PvCl in solutions of pH 1.0–6.2 at 25[ddot]C. The standard electrode potentials were determined at different temperatures and used to calculate the isothermal coefficient of the electrode. The electrode showed very good selectivity for Pv with respect to a large number of inorganic and organic cations. The potentiometric titration and standard addition methods were used to determine Pv in pure solutions and in pharmaceutical preparations.

Atomic emission spectrometric determination of antazoline, hydralazine and amiloride hydrochlorides, and quinine sulfate based on formation of ion associates with manganese thiocyanate

Ion associate complexes of the hydrochlorides of antazoline (1), hydralazine (2) and amiloride (3), and quinine sulfate (4) with [Mn(SCN)4]2– were precipitated and their solubilities were studied as a function of pH, ionic strength and temperature. The optimum conditions for the complete precipitation of the ion associate were, thus, elucidated. An accurate and precise method using atomic emission spectrometry for the determination of the investigated drugs in pure solutions and in pharmaceutical preparations is reported. The drugs can be determined by this method in the ranges 0.3–3.0, 0.19–1.96, 0.3–3.0 and 0.78–7.82 mg per 25 ml solutions of (1), (2), (3) and (4), respectively.

The determination of phosphonate base scale inhibitors in brines by plasma spectrometry

The determination of phosphonate base scale inhibitors in brines by direct current plasma (DCP) and inductively coupled plasma atomic emission spectrometry (ICP-AES) is described. The first method is based on a direct nebulization of the brine samples and plasma using the phosphorus line at 213.618 nm. The second method involves extraction of phosphorus as phospho-antimonyl molybdate complex into methylisobutyl ketone (MIBK) phase and analysis of the extract for molybdenum using the Mo 313.260 nm line. Comparison between the proposed methods and an established recommended method [1] shows excellent agreement between the results in addition to the sensitivity and ease of automation provided by AES.

Some observations on a new adiphenine-selective plastic membrane electrode based on adipheninium tetraphenylborate

Abstract A new adiphenine (Ad) ion-selective PVC membrane electrode based on the ion-pair complex of Ad with sodium tetraphenylborate was prepared and its performance characteristics were studied. The electrode exhibited a linear response with a good Nernstian slope over a relatively wide range of concentration. Up to 24 h continuous soaking, the calibration graph slope was constant at 53.0 mV/concentration decade, at 25 °C, then it decreased gradually as the time of soaking increases reaching 41 mV/decade after 11 days. The changes in pH did not affect the electrode performance within the range 2.2–7.5. The standard electrode potentials were determined at different temperatures and used to calculate the isothermal coefficient of the electrode. The electrode showed very good selectivity for Ad with respect to a large number of inorganic and organic cations. The standard addition method and potentiometric titration were used to determine Ad in pure solutions and in a pharmaceutical preparation.