Formation Of Ion-pair Complex Research Articles

Ion-Pair Extractive Spectrophotometric Assay of Terbinafine Hydrochloride in Pharmaceuticals and Spiked Urine Using Bromocresol Purple

Two simple, rapid, selective, and sensitive methods were developed and validated for the determination of terbinafi ne hydrochloride (TBH) in pharmaceuticals and urine. The fi rst method (method A) is based on the formation of a yellow ion-pair complex of TBH and bromocresol purple (BCP), a sulfonephthalein dye, in Walpole buffer of pH 3.61, which was extracted into chloroform and investigated at 420 nm. For the second method (method B) the drug–dye ion-pair was broken in alkaline KOH medium, and the resulting free dye color was measured at 610 nm. All variables were studied to optimize the reaction conditions. The regression analysis of Beer’s law plots showed good correlation in the concentration ranges of 1–10 and 0.1–2.0 μg/mL for method A and method B, respectively. Molar absorptivity values were 2.99 × 104, and 1.51×105 L/(mol × cm) for measurements by these methods. The methods were also validated for limits of detection (LOD) and quantifi cation (LOQ), intra-day and inter-day accuracy and precision, selectivity, robustness and ruggedness. The composition of the ion-pair (drug–dye) used in the method A was found to be 1:1 by both mole-ratio and Job's methods. The developed methods were applied to tablets, and the results were in good agreement with the label claim and those of the reference method. Because of its high sensitivity, method A was applied to spiked human urine with percent recoveries in the range 96.58-107.3 and a standard deviation <2%.

ChemInform Abstract: Pyrrole, Imidazole, and Triazole Derivatives as Ion‐Pair Recognition Receptors

AbstractReview: [32 refs.

A Versatile Approach Based on Ion-Pair Complex Formation on Oxide Surface for Effective Removal of Anionic Organic Dyes

A Versatile Approach Based on Ion-Pair Complex Formation on Oxide Surface for Effective Removal of Anionic Organic Dyes

Development spectrophotometric method of determination mebhydrolin in dosage forms

Allergic diseases have a clear tendency to increase worldwide. Mebhydrolin napadizilat is one of the most famous antihistamines H1-receptor blockers. Mebhydrolin high therapeutic activity, as well as low price leads to its popularity. Drugs based on it are produced by leading pharmaceutical companies in Ukraine. The development of simple and precise methods for quantitative determination of mebhydrolin in dosage forms is an actual problem of modern pharmaceutical analysis. Aim : The development of high sensitive, convenient and cheap methods for spectrophotometric quantitative determination of mebhydrolin in pharmaceutical phormulations. The methods validation according to the requirements of the State Pharmacopoeia of Ukraine. Methods : Absorption of the reaction products of mebhidrolin and bromtymol blue was measured in the wavelength range of 350-700 nm using spectrophotometer Specord 200. Results : A new spectrophotometric method for quantitative determination of mebhydrolin was developed. The method is based on mebhydrolin interaction with bromothymol blue in chloroform with ion-pair complex formation (maximum absorption at 412 nm). The new technique is applied to dosage forms - tablets, dragees and pellets produced by Ukrainian pharmaceutical companies. Main characteristics of validation requirements of the State Pharmacopoeia of Ukraine were determined. It is proved that the method can be correctly reproduced and is suitable for use in pharmaceutical and other chemical analytical laboratories

Extractive spectrophotometric determination of five selected drugs by ion-pair complex formation with bromothymol blue in pure form and pharmaceutical preparations

Simple, precise, selective, and expeditious spectrophotometric methods have been developed for the determination of itopride (ITO), midodrine (MID), diclofenac (DIC), mesalamine (MES), and sumatriptan (SUM) in their pure form as well as in pharmaceutical preparations. The method was based on ion-pair complex formation between the drugs and anionic dye, bromothymol blue in an acidic medium (pH 2.0–4.0). The yellow colored complexes formed were quantitatively extracted into chloroform and measured at 411, 410, 413, 412, and 414 nm wavelength for ITO, MID, DIC, MES, and SUM, respectively. Beer’s law was obeyed in the concentration range of 3.0–30 µg/mL for ITO, 1.0–20 µg/mL for MID, 1.5–40 µg/mL for DIC, 1.2–12 µg/mL for MES, and 0.5–15 µg/mL for SUM. The stoichiometry of the complexes formed between the drugs and the dye was 1:1 as determined by Job’s method of continuous variation. The association constant (KIP) of the ion-pair complexes formed was evaluated using Benesi–Hildebrand equation. Limit of detection, limit of quantification, and Sandell’s sensitivity of the methods were also estimated. The proposed methods were successfully employed for the determination of these drugs in their pharmaceutical dosage forms.

SPECTROPHOTOMETRIC METHODS FOR THE ESTIMATION OF DULOXETINE HYDROCHLORIDE IN BULK AND IN PHARMACEUTICAL DOSAGE FORM

Three simple, accurate, sensitive and economical spectrophotometric methods have been developed and subsequently validated for determination of duloxetine hydrochloride in bulk and pharmaceutical formulation. Method A is an extractive spectrophotometric method based on formation of ion-pair complexes of duloxetine hydrochloride with Solochrome Black T, to form pink colored chromogen, which showed a maximum absorption at 512 nm, and obeys Beer’s law in the concentration range of 2-10 μg/mL. Method B is based on the formation of charge transfer complexation reactions of duloxetine hydrochloride with picric acid to form a yellow colored chromogen, which showed maximum absorption at 420 nm and obeys Beer’s law in the concentration range of 5-25 μg/mL. Method C is a UV spectrophotometric method using isopropyl alcohol as solvent, in which absorption maxima was at 290 nm, Beer’s law obeyed in the concentration range of 5-30 μg/mL. The validation of the above methods was done and the results demonstrated that, the procedures were accurate, precise and reproducible. So, the proposed methods can be applied for the routine analysis of duloxetine hydrochloride in bulk drug and in its tablet dosage form.

Extraction of hydrogen chloride by a coupled reaction-solvent extraction process

A coupled reaction-solvent extraction process was used to remove HCl from a simulated distiller waste. The extraction performances of various extractants and diluents were compared and the apparent basicity of N235 (a mixture of tertiary amines) in various diluents was determined. The best results were obtained using N235 and isoamyl alcohol as the extractant and diluent, respectively. The yield of HCl from the coupled extraction was 75% with this extraction system. The mechanisms for the removal of HCl in both the direct and coupled extractions were investigated. For the coupled extraction, the formation of an R3NHCl ion-pair complex was involved in the HCl removal. For the direct extraction, the mechanism involved the formation of hydrogen bonds at high concentrations of HCl.

Application of Ion-Pair Complex Formation in Spectrophotometric Analysis of Dexlansoprazole

Application of Ion-Pair Complex Formation in Spectrophotometric Analysis of Dexlansoprazole

WITHDRAWN: Preconcentration and indirect quantification of trace nitrite, nitrate and total nitrite in selected beverage and milk samples using ion-pairing cloud-point extraction with acridine orange

Abstract A new indirect preconcentration method was developed for micellar-sensitive detection of trace nitrite as analyte by spectrophotometry. It is based on selective ion-pairing complex formation of triiodide ion, I3− with acridine orange, AOH+ (3,6-bis(dimethylamino) acridine) at pH 4.0 and its cloud-point extraction (CPE) with Triton X-114 as extracting agent. The extracted surfactant-rich phase is diluted with acetonitrile, and its absorbance is measured against analyte blank at 450 nm. The variables affecting CPE efficiency were investigated, and a set of optimized conditions was obtained. The calibration graph was rectilinear in the range of 1.5–150 μg L−1. The detection limit was 0.42 μg L−1 with a precision lower than 4.1%. The validation was statistically confirmed by analysis of a certified reference material. The method was successfully applied to determination of nitrite, nitrate and total nitrite in selected beverage and milk samples before and after reduction with two different reducing agents.

Optimized and validated spectrophotometric determination of two antifungal drugs in pharmaceutical formulations using an ion-pair complexation reaction

Simple, rapid, cost-effective, sensitive and extractive spectrophotometric methods were developed for the determination of two antifungal drugs (i.e., sertaconazole nitrate (SER) and miconazole nitrate (MCO)) in pure and dosage forms. The methods are based on the formation of ion-pair complexes between the drugs and acid dyes (i.e., bromocresol purple (BCP), bromophenol blue (BPB) and methyl orange (MO)) in acidic buffer solutions. The formed complexes were extracted with chloroform and measured at 410, 416 and 427nm for SER and at 408, 415 and 426nm for MCO using BCP, BPB and MO, respectively. The analytical parameters and their effects on the reported systems were investigated. Beer's law was obeyed in the 1.0–20 and 1.0–24μgmL−1 ranges for SER and MCO, respectively. The composition of the ion pairs was determined to be 1:1. The molar absorptivity, Sandell sensitivity, limits of detection and limits of quantification were calculated. Other method validation parameters, such as precision, accuracy, robustness, ruggedness and selectivity, were satisfactory. The proposed methods have been successfully applied for the analysis of the studied drugs in their pure and dosage forms. Statistical comparison of the results with the reference methods indicated excellent agreement and no significant difference in accuracy and precision.

Spectrophotometric Determination of Macrolides Using Bromocresol Green in Pharmaceutical Formulations and Urine Samples

Simple and rapid methods have been developed for the determination of azithromycin, roxithromycin and erythromycin in bulk and pharmaceutical formulations. The methods were based on the formation of bluish-green ion pair complexes of these antibiotics with bromocresol green (BCG) in acetonitrile-ethanol medium. 2:1 complexes were formed between the drug and reagent almost instantaneously with absorption maxima at 630 nm, 620 nm and 625 nm for the three drugs respectively. Under optimum conditions, calibration curves were found to be linear over the range of 4-46 µg mL-1, 3-53 µg mL-1 and 7-73 µg mL-1respectively for the three drugs. The detection limits were found to be 0.19, 0.56 and 0.30 µg mL-1. The methods were subjected to analytical quality control. Recovery studies and interference studies were carried out. The proposed methods were successfully applied to the determination of these drugs in their pharmaceutical formulations and spiked urine samples.

Determination of Buspirone HCl in Commercial Dosage Forms by Extractive Spectrophotometric Method and Comparison by HPLC Method

An extractive spectrophotometric method has been developed for the determination of buspirone HCl in tablets. It was based on the ion-pair complex formation between buspirone and bromothymol blue in presence of disodium hydrogen phosphate and citric acid buffer solution of pH 4.0 which is extractable in chloroform. The extracted complex showed maximum absorbance at 412 nm. Beer’s law was obeyed in the concentration range of 1.25-30 μg ml-1. Various factors affecting the reaction conditions were carefully studied and optimized. Validation parameters based on the guidelines of International Conference on Harmonisation, USA were followed. Effect of common excipients used as additives has been tested and the tolerance limit was calculated for the determination of buspirone HCl. Limits of detection and quantitation were 0.165 and 0.499 g ml-1, respectively. Proposed method has been successfully applied for the determination of buspirone HCl in pharmaceutical formulations. High performance liquid chromatographic method was employed using 250 mm × 4.6 mm i.d., 5-m particle, reversed phase C18 column with 70:30 (v/v) methanol-0.01M NaH2PO4 buffer as a mobile phase at a flow rate of 0.8 ml min-1 and UV detection at 240 nm for best separation of buspirone. Results obtained by the proposed method were statistically compared with the HPLC reference method using t- and F- values and found no significant difference between the two methods. The proposed method can be used as an alternate method for routine quality control analysis of buspirone HCl in pharmaceutical formulations.

Spectrophotometric Determination of Some Antibiotics Using Bromophenol Blue as Ion Pair Reagent

Objective: Simple and rapid methods have been developed for the determination of azithromycin, sparfloxacin and cephalexin monohydrate in bulk and pharmaceutical formulations. Method: These methods were based on the formation of bluish-green ion pair complexes of these antibiotics with bromophenol blue (BPB). Acetonitrile was used as a solvent for azithromycin and sparfloxacin whereas methanolacetonitrile medium for cephalexin monohydrate. Results: 2:1 complexes were formed between the drug and reagent almost instantaneously with absorption maxima 595 nm, 620 nm, 600 nm for the three drugs respectively. Different parameters such as effect of time, effect of reagent concentration were optimised. Under optimum conditions, calibration curves were found to be linear over the range of 0-50 μg mL-1 for azithromycin, 10-80 μg mL-1 for sparfloxacin and 10-170 μg mL-1 for cephalexin monohydrate respectively. The detection limits were found to be 0.10 μg mL-1, 0.21 μg mL-1 and 1.69 μg mL-1 with Sandell’s sensitivity 0.0559 μg cm-2, 0.1034 μg cm-2 and 1.3920 μg cm-2 respectively for the three drugs. Stability constant (log K) was found to be 6.19 ± 0.04, 5.00 ± 0.07 and 4.05 ± 0.05 showing high stability of the complexes. Molar absorptivity was found to be 1.369×104 L mol-1 cm-1, 3.774×103 L mol-1 cm-1 and 2.620×102 L mol-1 cm-1 with Gibb’s free energy change -2.725×103 kJ mol-1, -2.393×103 kJ mol-1 and -1.938×103 kJ mol-1. These methods were subjected to analytical quality control. Accuracy, precision, recovery and interference studies have been carried out. Conclusion: The proposed methods were successfully applied to the determination of these drugs in their pharmaceutical formulations and human urine samples.

Spectrophotometric Determination of Cefixime Trihydrate in Pharmaceutical Formulations Based on Ion-Pair Reaction with Bromophenol Blue.

Cefixime trihydrate is a broad spectrum cephalosporin antibiotic, effective against gram-positive and gram-negative bacterial infections. Simple and rapid method has been developed for the determination of cefixime trihydrate in bulk and pharmaceutical formulations. This method was based on the formation of bluish-green ion-pair complex of cefixime trihydrate with bromophenol blue in dimethyl sulfoxide (DMSO)–acetonitrile medium. Different parameters were studied and optimized. A 2:1 complex was formed between the drug and reagent almost instantaneously at room temperature which has λmax of 610 nm. Under optimum conditions, calibration curve was found to be linear over the range of 10–130 μg mL−1. The method was subjected to analytical quality control. The limit of detection was found to be 1.08 μg mL−1. Recovery studies and interference studies were carried out. The proposed method was successfully applied to the determination of cefixime trihydrate in bulk and pharmaceutical formulations with high precision and accuracy.

A sensitive emulsification liquid phase microextraction coupled with on-line phase separation followed by HPLC for trace determination of sulfonamides in water samples.

For the first time, ion-pair based emulsification liquid phase microextraction coupled with a novel approach for phase separation followed by high performace liquid chromatgraphy (HPLC) was utilized for trace determination of sulfonamides in water samples. After the formation of ion-pair complex with a cationic surfactant, sulfonamides were extracted into the drops of dispersed organic extracting solvent. Then, the cloudy solution was passed through an in-line filter located in a suitable holder and was separated based on emulsion filtration. By changing the HPLC valve position, the filter was laid in the mobile phase path, and the extraction phase was eluted by the mobile phase and introduced into the separation column for analysis. The effects of important parameters, such as type of extraction solvent, type of ion-pair agent and its concentration, pH of sample solution, ionic strength, and volume of extraction phase, on the extraction efficiency, were investigated and optimized. Under optimal conditions, the linear range, limits of detection, and precision (relative standard deviations) were 0.3-100, 0.1-0.3 μg L(-1), and 4.7-5.8%, respectively. Preconcentration factors (PFs) for the compounds studied were obtained in the range of 268-664. These PFs correspond to extraction recoveries in the range of 41-97%. The sample throughput of the method was 3 samples per hour, regarding 20 min analysis time for a single procedure. Finally, the method was successfully applied to determine the selected sulfonamides in some water samples.

Extraction-Free Ion-Pair Methods for the Assay of Trifluoperazine Dihydrochloride in Bulk Drug, Tablets, and Spiked Human Urine Using Three Sulfonphthalein Dyes

Three simple and sensitive extraction-free spectrophotometric methods are described for the determination of trifluoperazine dihydrochloride (TFH). The methods are based on ion pair complex formation between the nitrogenous compound trifluoperazine (TFP) converted from trifluoperazine dihydrochloride and sulfonphthalein dyes, namely, bromocresol green (BCG), bromothymol blue (BTB), and bromophenol blue (BPB) in dichloromethane medium in which all the above experimental variables were circumvented. The colored products are measured at 425 nm in the BCG method, 415 nm in the BTB method, and 420 nm in the BPB method. The stoichiometry of the ion-pair complexes formed between the drug and dye (1:1) was determined by Job’s continuous variations method, and the stability constants of the complexes were also calculated. These methods quantify TFP over the concentration ranges of 1.25–20.0 μg/ml in the BCG method, 1.5–21.0 μg/ml in the BTB method, and 1.5–18.0 μg/ml in the BPB method. The molar absorptivity (l·mol–1·cm–1) and Sandell sensitivity (ng/cm2) were calculated to be 2.06·104 and 0.0197; 1.82·104 and 0.0224; and 2.22·104 and 0.0183 for the BCG, BTB, and BPB methods, respectively. The methods were successfully applied to the determination of TFP in pure drug, pharmaceuticals, and in spiked human urine with good accuracy and precision.

Extractive Spectroscopic Determination of Lansoprazole in Pharmaceutical Dosage Form

Two simple and sensitive extractive spectrophotometric methods have been described for the assay of Lansoprazole (LPZ) either in pure form or in pharmaceutical formulations. The methods were based on the formation of ion-pair complex between LPZ and Metanil Yellow (MY) - Method- A and methyl orange (MO)- Method- B, at pH 2.5 has been described. The formed complex were extracted quantitatively into chloroform and measured at 440 nm and 450 nm with MY and MO respectively. Beer's law was obeyed in the concentration range of 20-70 µg mL -1 and 6-16 µg mL -1 with molar absorptivity of 1.329 x 10 -8 and 1.822 x 10 -8 L mol -1 cm -1 with MY and MO respectively. Statistical comparison of the results of the proposed method with those of the reference method shows excellent agreement and indicates no significant difference in accuracy and precision. The limits of detection and quantification have been determined for two methods. Both the methods have been validated as per the guidelines of ICH. The methods have been applied to the determination of drug in commercial capsules and results of analysis were validated statistically through recovery studies

Extraction-free Spectrophotometric Determination of Pyrantel Pamoate in Pharmaceuticals

The objective of this work was to develop and validate two direct, simple, highly sensitive, rapid and extraction-free spectrophotometric methods for the determination of Pyrantel pamoate (PYP) in commercial dosage forms. The methods are based on the formation of ion-pair complex between the base form of Pyrantel pamoate (PYL) and two sulphonthalein dyes, namely, phenol red (method A) and thymol blue (method B), followed by the measurement of absorbance at 430 nm and 420 nm respectively. Conformity to Beer’s law enabled the assay of drug in the range 0.02-0.5 and 0.05-0.8 µg ml –1 with apparent molar absorptivities of 5.11×10 5 and 2.55×10 5 l mol –1 cm –1 for method A and method B, respectively. The Sandell sensitivity values, limits of detection (LOD) and quantification (LOQ) values have also been reported for both the methods. The stoichiometry of the ion-pair complexes as evaluated by Job’s continuous variations method was 1:2 and the conditional stability constants (log K f ) were calculated to be 6.92 and 8.19 for method A and method B, respectively. The accuracy and precision of the methods were evaluated on intra-day and inter-day basis; the relative error (%RE) was < 2.17% and the relative standard deviation (RSD) was < 1.77%. The methods were successfully applied to the determination of drug in tablets without interference by the common co-formulated substances. Statistical comparison of the results with the reference method showed good agreement and indicated that no significant difference in accuracy and precision.

Spectrophotometric determination of β-adrenergic antagonists drugs via ion-pair complex formation using MO and EBT

Two simple, rapid and sensitive spectrophotometric methods have been proposed for the assay of bisoprolol fumarate (BSF), propranolol hydrochloride (PRH), and timolol maleate (TIM) either in bulk or in pharmaceutical formulations. The methods are based on the reaction of the selected drugs with methyl orange (MO) and eriochrome black T in acidic buffers, after extracting in dichloromethane and measured quantitatively with maximum absorption at 428 and 518 nm for MO and EBT, respectively. The analytical parameters and their effects on the reported systems are investigated. The extracts are intensely colored and very stable at room temperature. The calibration graphs were linear over the concentration range of 0.8–6.4, 0.4–3.6, 0.8–5.6 μg/mL for BSF, PRH, and TIM, respectively, with MO and 0.8–6.4, 0.4–3.2, and 0.8–8.0 μg/mL for BSF, PRH, and TIM, respectively, with EBT. The stoichiometry of the complexes was found to be 1 : 1 in all cases. The proposed methods were successfully extended to pharmaceutical preparations. Excipients used as additive in commercial formulations did not interfere in the analysis. The proposed methods can be recommended for quality control and routine analysis where time, cost effectiveness and high specificity of analytical technique are of great importance.

Sensitive and selective spectrophotometric assay of piroxicam in pure form, capsule and human blood serum samples via ion-pair complex formation

A simple, accurate and highly sensitive spectrophotometric method has been developed for the rapid determination of piroxicam (PX) in pure and pharmaceutical formulations. The proposed method involves formation of stable yellow colored ion-pair complexes of the amino derivative (basic nitrogen) of PX with three sulphonphthalein acid dyes namely; bromocresol green (BCG), bromothymol blue (BTB), bromophenol blue (BPB) in acidic medium. The colored species exhibited absorption maxima at 438, 429 and 432nm with molar absorptivity values of 9.400×103, 1.218×103 and 1.02×104Lmol−1cm−1 for PX–BCG, PX–BTB and PX–BPB complexes, respectively. The effect of optimum conditions via acidity, reagent concentration, time and solvent were studied. The reactions were extremely rapid at room temperature and the absorbance values remained constant for 48h. Beer’s law was obeyed with a good correlation coefficient in the concentration ranges 1–100μgmL−1 for BCG, BTB complexes and 1–95μgmL−1 for BPB complex. The composition ratio of the ion-pair complexes were found to be 1:1 in all cases as established by Job’s method. No interference was observed from common additives and excipients which may be present in the pharmaceutical preparations. The proposed method was successfully applied for the determination of PX in capsule and human blood serum samples with good accuracy and precision.