The Ion Associates of Methyl-, Ethyl- and Isopropyl Derivatives of Dialkylaminoethyl Dialkylamidofluorophosphate with Bromophenol Blue

1992 ◽  
Vol 57 (1) ◽  
pp. 56-63 ◽  
Author(s):  
Emil Halámek ◽  
Zbyněk Kobliha
Keyword(s):  
Extraction Efficiency ◽  
Ion Pairs ◽  
Amino Nitrogen ◽  
Ion Pair ◽  
Amide Group ◽  
Bromophenol Blue ◽  
Amino Group ◽  
Methyl Ethyl ◽  
Derivatives Of

Nine new Tammelin esters were studied on the basis of the chloroform extracts of their ion associates with bromophenol blue. A study was made of the effect of the alkyl on the amino and amido groups of dialkylaminoethyl dialkylamidofluorophosphate and on the extraction efficiency of the ion pair. An increase in the number of carbon atoms on the amide group leads to the increase in the extraction efficiency of the ion pairs as a consequence of the increasing hydrophobicity. A further contribution to the increase in the extraction efficiency with increasing number of carbon atoms in the alkyls of the amino nitrogen is clearly retarded by the increasing basicity of the amino group. An extraction spectrophotometric determination of the test derivatives of dialkylaminoethyl dialkylamidofluorophosphate was developed and the interferences from precursors in the synthesis were examined.

scholarly journals Spectrophotometric determination of dothiepin hydrochloride in pharmaceuticals through ion-pair complexation reaction

2012 ◽  
Vol 18 (2) ◽  
pp. 339-347 ◽  
Author(s):  
Sameer Abdulrahman ◽  
Kanakapura Basavaiah
Keyword(s):  
Ion Pair ◽  
Pure Form ◽  
Bromocresol Green ◽  
Bromophenol Blue ◽  
Complexation Reaction ◽  
Conditional Stability ◽  
Conditional Stability Constant ◽  
Accuracy And Precision ◽  
Significant Difference

Two simple, sensitive and extraction-free spectrophotometric methods are described for the determination of dothiepin hydrochloride (DOTH) both in pure form and in pharmaceutical tablets. The methods are based on ion-pair complex formation between dothiepin base (DOT) and two acidic dyes, namely, bromophenol blue (BPB) or bromocresol green (BCG) with absorption maximum at 425 nm for BPB method or 430 nm for BCG method. Beer?s law is obeyed over the concentration ranges of 1.0-15.0 and 1.0-17.5 ?g mL-1 DOT for BPB and BCG methods, respectively. The molar absorptivity values and Sandell?s sensitivity values are reported for both methods. The limits of detection (LOD) and quantification (LOQ) were calculated to be 0.18 and 0.53 ?g mL-1 for BPB method, and 0.17 and 0.50 ?g mL-1 for BCG method, respectively. The stoichiometry of the complex in either case was found to be 1: 1 and the conditional stability constant (KF) of the complexes has also been calculated. The proposed methods were applied successfully to the determination of DOTH in pure form and in its tablet form with good accuracy and precision. Statistical comparison of the results was performed using Student's t-test and variance ratio F-test at 95% confidence level and there was no significant difference between the official and proposed methods with regard to accuracy and precision. Further, the validity of the proposed methods was confirmed by recovery studies via standard addition technique.

scholarly journals Spectrophotometric Determination of Doxazosin Mesylate in Tablets by Ion-Pair and Charge-Transfer Complexation Reactions

2009 ◽  
Vol 92 (1) ◽  
pp. 131-137 ◽  
Author(s):  
Zeynep Aydomu ◽  
Asli Barla
Keyword(s):  
Charge Transfer ◽  
Ion Pair ◽  
Bromophenol Blue ◽  
Bromocresol Purple ◽  
Charge Transfer Reaction ◽  
Accuracy And Precision ◽  
Doxazosin Mesylate ◽  
Significant Difference ◽  
Complexation Reactions

Abstract Two accurate, easy spectrophotometric methods for the determination of doxazosin mesylate were described. The first method was based on the formation of ion-pair complexes with the acidic sulfophthalein dyes bromocresol purple (BCP) and bromophenol blue (BPB) in pH 3.3 and 4.5 citratephosphate buffer, respectively. The formed complexes were extracted into dichloromethane, and their absorbance was measured at 403 and 410 nm for BCP and BPB, respectively. The second method was based on the charge transfer reaction of the drug as an n-electron donor with either 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) or 7,7,8,8-tetracyanoquinodimethane (TCNQ) as -acceptors, to give colored radical anions. The absorbances of products were measured at 457 nm in acetonitrile and 838 nm in methanol for DDQ and TCNQ, respectively. Under the optimum reaction conditions, Beer's law was obeyed with a good correlation coefficient (r = 0.99970.9999) in the concentration ranges 3.018.0, 3.020.0, 15.095.0, and 10.0100.0 g/mL for the BCP, BPB, DDQ, and TCNQ methods, respectively. Limits of detection of the BCP, BPB, DDQ, and TCNQ methods were 0.314, 0.408, 1.935, and 1.610 g/mL, respectively. The limits of quantification were 1.045, 1.360, 6.449, and 5.367 g/mL, respectively. The parameters molar absorptivity, precision, accuracy, recovery, robustness, and stability constant were studied. The proposed methods were successfully applied for determination of the drug in tablets with good accuracy and precision. Statistical comparison of the results with those obtained by a reported method showed good agreement and indicated no significant difference in accuracy and precision.

Rapid Colorimetric Assay of Trimethoprim and Sulfamethoxazole in Pharmaceuticals

1983 ◽  
Vol 66 (6) ◽  
pp. 1447-1449 ◽  
Author(s):  
Asis K Sanyal ◽  
Dinabandhu Laha
Keyword(s):  
Solvent Extraction ◽  
Colorimetric Assay ◽  
Pharmaceutical Preparations ◽  
Ion Pair ◽  
Pair Formation ◽  
Bromophenol Blue ◽  
Colorimetric Determination ◽  
Ion Pair Formation ◽  
Subsequent Measurement

Abstract A method is described for the direct colorimetric determination of trimethoprim and sulfamethoxazole in pharmaceutical preparations, without prior separation. Estimation of trimethoprim is based on its ion-pair formation with bromophenol blue and subsequent measurement of absorbance of the ionpair at 418 nm. Estimation of sulfamethoxazole is possible without removal of trimethoprim by solvent extraction.

scholarly journals Factorial design-assisted spectroscopic determination of oxybutynin hydrochloride

2021 ◽  
Vol 8 (11) ◽  
Author(s):  
Eman Yosrey ◽  
Heba Elmansi ◽  
Zeinab A. Sheribah ◽  
Mohamed El-Sayed Metwally
Keyword(s):  
Ion Pair ◽  
Critical Parameters ◽  
Spectroscopic Methods ◽  
Amino Group ◽  
Quenching Mechanism ◽  
Spectrophotometric Measurement ◽  
Volmer Plot ◽  
Tertiary Amino ◽  
Oxybutynin Hydrochloride

In this study, we have developed two facile spectroscopic methods for quantifying oxybutynin (OBT) hydrochloride in its pure form and tablets using design of experiments (DOEs). The spectroscopic methods depended on the ion-pair complex formation between the tertiary amino group in the drug and eosin in 0.2 M acetate buffer of pH 4. Method I involves spectrophotometric measurement of the absorbance of the developed complex at 550 nm and showed linearity through 1.0–10.0 µg ml −1 . Method II involves spectrofluorometric measurement of the quenching influence of OBT on the native fluorescence of eosin (λ excitation/λ emission of 304/548 nm) and showed linearity through 1.0–6.0 µg ml −1 . Critical parameters were identified through preliminary trials and optimized using the DOE. Additionally, the quenching mechanism was investigated and the pathway of the reaction was postulated. The fluorescence quenching constant and thermodynamic parameters were explored using the Stern–Volmer plot and Van't Hoff graph, respectively. Assessments conducted via analytical ecoscale revealed the ‘excellent-greenness’ of the methodology. The two methods have the potentials of being green and fast compared with other reported methods.

scholarly journals Validated Extractive Spectrophotometric Method for Determination of Domperidone in Pharmaceutical Formulations

2015 ◽  
Vol 17 (1) ◽  
pp. 25-31
Author(s):  
Jasmin Shah ◽  
M Rasul Jan ◽  
Muhammad Tariq Shah
Keyword(s):  
Acidic Medium ◽  
Pharmaceutical Formulations ◽  
Pharmaceutical Journal ◽  
Bromothymol Blue ◽  
Hplc Method ◽  
Ion Pair ◽  
Bromophenol Blue ◽  
Spectrophotometric Methods ◽  
New Methods

Simple, precise and sensitive extractive spectrophotometric methods have been developed for the determination of domperidone in pharmaceutical formulations. The new methods involve the formation of colored extractable ion pair complexes of the drug with bromothymol blue (BTB) and bromophenol blue (BPB) in acidic medium. The effects of various parameters like pH, reagent concentration and shaking time were studied. The extracted complexes of domperidone showed maximum absorbance at 410 nm with BTB and at 415 nm with BPB dye. The stiochiometry of the reaction between domperidone, BTB and BPB was found to be 1: 4. Domperidone was found to obey Beer’s law in the concentration ranges of 0.6-35 ?g/ml, 1-30 ?g/ml with BTB and BPB, respectively. The method has been applied successfully for the determination of domperidone in commercial tablets and suspension samples. The results obtained by the proposed methods were validated statistically and compared with the official HPLC method. DOI: http://dx.doi.org/10.3329/bpj.v17i1.22310 Bangladesh Pharmaceutical Journal 17(1): 25-31, 2014

scholarly journals Application of ion pair complexes to design novel potentiometric membrane sensors for direct determination of frusemide in pharmaceuticals

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Nagaraju Rajendraprasad ◽  
Kanakapura Basavaiah
Keyword(s):  
Limit Of Detection ◽  
Direct Determination ◽  
Standard Addition ◽  
Ion Pair ◽  
Bromocresol Green ◽  
Bromophenol Blue ◽  
Experimental Parameters ◽  
The Mean

Abstract Background Fabrication of two membrane sensors using two acidic indicators among sulphonthalein dyes, namely bromophenol blue (BPB) and bromocresol green (BCG), and their use as indicative electrodes for the quantification of frusemide (FUR) is presented. The ion pair complexes of FUR with BPB or BCG are used to prepare the membranes in THF solvent, PVC matrix and dibutyl phthalate (DBP) as plasticizer and subsequently to fabricate FUR-BPB (Sensor I) and FUR-BCG (Sensor II) sensors. Results Sensors I and II are employable to determine 2.4 × 10-5–2.4 × 10-3 mol/L FUR at operative pH of 3.71. The calibration curve between the potentials against the concentration of FUR yielded the slopes of 58.73 ± 1 and 57.66 ± 1 mV/decade, respectively, using Sensors I and II, and this confirmed the Nernstian behaviour. Satisfactory correlation was obtained between the measured potentials and FUR concentration with the proposed sensors, and this was revealed by regression coefficient values of 0.9987 and 0.9980 for Sensors I and II, respectively. The LOD (limit of detection) values were calculated and reported for both the sensors. The experimental parameters were optimised to yield acceptable characteristics of both the sensors in the context of performance. The role of excipients of tablets and interferences were assessed by standard addition protocol. The obtained results confirmed the ineffective role of excipients of tablets and foreign species used as interferents. Conclusion The designed sensors were validated to confirm the accurate, precise, robust and rugged functioning in determining FUR. The mean of recovered FUR, close to 100%, revealed the acceptable and effective functioning of the proposed sensors. Excellent results were obtained by FUR tablets’ analysis using both the sensors.

scholarly journals Spectrophotometric and theoretical studies on the determination of etilefrine hydrochloride in pharmaceutical formulations and biological samples

2017 ◽  
Vol 16 (10) ◽  
pp. 2487-2500
Author(s):  
Ahmed Mohamed El Defrawy ◽  
Amr Lotfy Saber
Keyword(s):  
Methyl Orange ◽  
Correlation Coefficient ◽  
Density Functional ◽  
Ion Pairs ◽  
Ion Association ◽  
Pharmaceutical Formulations ◽  
Ion Pair ◽  
Bromocresol Green ◽  
Geometrical Parameters

Purpose: To develop a simple and cost effective spectrophotometric method for the determination of etilefrine hydrochloride (ET) in pharmaceutical formulations and human plasma.Methods: The method is based on extraction of ET into chloroform as ion-pair  complexes with bromocresol green (BCG) and methyl orange (MO) in acidic medium. The interaction of ET with BCG and MO reagents were investigated using  B3LYP/6-31G(d) level of theory. The geometrical parameters of the interacting species and the ion pairs formed were characterized based on their frontier  molecular orbitals, atomic charges, electrostatic potential map, as well as NBO analysis.Results: The colored species exhibited absorption maxima at 410 and 479 nm for the two systems in universal buffer of pH range (3.0 - 3.5), with molar absorptivity of 2.4 × 104 and 1.7 × 104 Lmol-1cm-1, for BCG and MO methods, respectively. The methods demonstrated good linearity with correlation coefficient ranging from  0.9987 – 0.9991 in the concentration ranges 0.5 – 16 and 2.0 – 18 μgmL-1 for BCG and MO methods, respectively. The composition ratio of the ion-association complexes was 1:1 in all cases as established by Job’s method. Sandell,s  sensitivity, correlation coefficient, detection and quantification limits were also calculated. Molecular descriptors were obtained based on optimized structures of the molecules under investigation, by applying the B3LYP/6-31G(d) method, and used to interpret the mode of interaction between these molecules to form the investigated ion pairs.Conclusion: The proposed methods make use of simple reagents, which a basic  analytical laboratory can afford. No interference was observed from common  pharmaceutical excipients and additives. ETMO ion pair has a larger interaction energy (higher stability) than ET-BCG ion pair as inferred from their interaction energies.Keywords: Density functional theory, Etilefrine hydrochloride, Ion pair complex, Spectrophotometry, Bromocresol green, Methyl orange, Geometric analysis

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