scholarly journals Analytical Study for the Charge-Transfer Complexes of Pregabalin

2009 ◽  
Vol 6 (2) ◽  
pp. 332-340 ◽  
Author(s):  
Hesham Salem
Keyword(s):  
Charge Transfer ◽  
Pharmaceutical Preparation ◽  
Correlation Coefficients ◽  
Charge Transfer Complexes ◽  
Chloranilic Acid ◽  
Spectrophotometric Methods ◽  
Linear Relationships ◽  
Accuracy And Precision ◽  
Optimum Reaction ◽  
First Time

Studies were carried out, for the first time, to investigate the charge-transfer reactions of Pregabalin (PRE) asn-electron donor with various π-acceptors: 7,7,8,8-tetracyanoquinodimethane (TCNQ), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone (chloranilic acid,pCA), tetracyanoethylene (TCNE) and 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil). Different colored charge-transfer complexes and radical anions were obtained. Different variables affecting the reactions were studied and optimized. The formations of the colored complexes were utilized in the development of simple, rapid and accurate spectrophotometric methods for the analysis of PRE in pure form as well as in its pharmaceutical preparation. Under the optimum reaction conditions, linear relationships with good correlation coefficients (0.9995-0.9999) were found between the absorbance and the concentrations of PRE in the range of 8-400 µg mL-1. The limits of assays detection ranged from 0.60 to 8.11 µg mL-1. No interference could be observed from the additives commonly present in the capsules. The methods were successfully applied to the analysis of capsules that contain PRE, with good accuracy and precision; the recovery percentages ranged from 100.19±0.83 to 100.50±0.53. The results were compared favorably with the reported method.

scholarly journals Analytical Study for the Charge-Transfer Complexes of Risperidone in Pure and Dosage Forms

2016 ◽  
Vol 8 (3) ◽  
pp. 1745-1753
Author(s):  
F. Ibrahim ◽  
N. El-Enany ◽  
Sh. Shalan ◽  
Rasha Mostafa Elsharawy
Keyword(s):  
Charge Transfer ◽  
Reaction Pathway ◽  
Pharmaceutical Preparations ◽  
Comparison Method ◽  
Charge Transfer Complexes ◽  
Chloranilic Acid ◽  
Spectrophotometric Methods ◽  
Ich Guidelines ◽  
Optimum Reaction ◽  
Recovery Percentage

Two simple, accurate and sensitive spectrophotometric methods were carried out to investigate through charge-transfer reactions of risperidone (RIS) as n-electron donor with various π acceptors: 7, 7, 8, 8-tetracyanoquinodimethane (TCNQ) and p-chloranilic acid (pCA). The absorbance of reaction product was measured at 842 and 520 nm for TCNQ and pCA reagents respectively. Different experimental parameters affecting the reactions were carefully studied. The reaction pathway was postulated. The proposed spectrophotometric method was utilized for the analysis of RIS in pure form as well as in its pharmaceutical preparations. Under the optimum reaction conditions, Beer’s law is obeyed over the concentration range of 1-12 µg mL-1 and 10-180 µg mL-1 for TCNQ and pCA respectively. The limit of assays detection (LOD) is 0.114 µg mL-1 and 2.55 µg mL-1 for TCNQ and pCA respectively. The mean recovery percentage was 99.72 ± 1.06 and 100.50 ± 1.07 for TCNQ and pCA respectively. The results were compared favorably with those obtained by comparison method. The proposed method was validated statistically according to ICH guidelines.

scholarly journals Development and Validation of Spectrophotometric Methods for Determination of Fluoxetine, Sertraline, and Paroxetine in Pharmaceutical Dosage Forms

2005 ◽  
Vol 88 (1) ◽  
pp. 38-45 ◽  
Author(s):  
Ibrahim A Darwish
Keyword(s):  
Correlation Coefficients ◽  
Dosage Forms ◽  
Pharmaceutical Dosage Forms ◽  
Factors Affecting ◽  
Spectrophotometric Methods ◽  
Linear Relationships ◽  
Relative Standard ◽  
Optimum Reaction ◽  
Standard Deviations

Abstract Three simple and sensitive spectrophotometric methods were developed and validated for determination of the hydrochloride salts of fluoxetine, sertraline, and paroxetine in their pharmaceutical dosage forms. These methods were based on the reaction of the N-alkylvinylamine formed from the interaction of the free secondary amino group in the investigated drugs and acetaldehyde with each of 3 haloquinones, i.e., chloranil, bromanil, and 2,3-dichloronaphthoquinone, to give colored vinylamino-substituted quinones. The colored products obtained with chloranil, bromanil, and 2,3-dichloronaphthoquinone exhibit absorption maxima at 665, 655, and 580 nm, respectively. The factors affecting the reactions were studied and optimized. Under the optimum reaction conditions, linear relationships with good correlation coefficients (0.9986–0.9999) were found between the absorbances and the concentrations of the investigated drugs in the range of 4–120 μg/mL. The limits of detection for the assays ranged from 1.19 to 2.98 μg/mL. The precision values of the methods were satisfactory; the relative standard deviations were 0.56–1.24%. The proposed methods were successfully applied to the determination of the 3 drugs in pure and pharmaceutical dosage forms with good accuracy; the recoveries ranged from 99.1 to 101.3% with standard deviations of 1.15–1.92%. The results compared favorably with those of reported methods.

scholarly journals Spectrophotometric Determination of Mycophenolate Mofetil as Its Charge-Transfer Complexes with Twoπ-Acceptors

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
K. B. Vinay ◽  
H. D. Revanasiddappa ◽  
M. S. Raghu ◽  
Sameer. A. M. Abdulrahman ◽  
N. Rajendraprasad
Keyword(s):  
Mycophenolate Mofetil ◽  
Charge Transfer ◽  
Correlation Coefficients ◽  
Reference Method ◽  
Standard Addition ◽  
Molar Absorptivity ◽  
Charge Transfer Complexes ◽  
Complexation Reaction ◽  
Chloranilic Acid

Two simple, selective, and rapid spectrophotometric methods are described for the determination of mycophenolate mofetil (MPM) in pure form and in tablets. Both methods are based on charge-transfer complexation reaction of MPM with p-chloranilic acid (p-CA) or 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in dioxane-acetonitrile medium resulting in coloured product measurable at 520 nm (p-CA) or 580 nm (DDQ). Beer’s law is obeyed over the concentration ranges of 40–400 and 12–120 μg mL−1MPM for p-CA and DDQ, respectively, with correlation coefficients (r) of 0.9995 and 0.9947. The apparent molar absorptivity values are calculated to be1.06×103and3.87×103 L mol−1 cm−1, respectively, and the corresponding Sandell’s sensitivities are 0.4106 and 0.1119 μg cm−1. The limits of detection (LOD) and quantification (LOQ) are also reported for both methods. The described methods were successfully applied to the determination of MPM in tablets. Statistical comparison of the results with those of the reference method showed excellent agreement. No interference was observed from the common excipients present in tablets. Both methods were validated statistically for accuracy and precision. The accuracy and reliability of the methods were further ascertained by recovery studiesviastandard addition procedure.

scholarly journals Spectrophotometric determination of repaglinide in tablets based on charge-transfer complexation reaction with chloranilic acid and dichloro-dicyano benzoquinone

2011 ◽  
Vol 17 (4) ◽  
pp. 469-476 ◽  
Author(s):  
Madathil Cijo ◽  
Kanakapura Basavaiah ◽  
Sameer Abdulrahman ◽  
K.B. Vinay
Keyword(s):  
Charge Transfer ◽  
Correlation Coefficients ◽  
Molar Absorptivity ◽  
Complexation Reaction ◽  
Chloranilic Acid ◽  
Subsequent Formation ◽  
Spectrophotometric Methods ◽  
Bulk Drug ◽  
Charge Transfer Complexation

Two simple, accurate, precise, inexpensive, selective and sensitive spectrophotometric methods are described for the determination of repaglinide (RPG) in bulk drug and its tablets. The methods were based on the charge- transfer complex reaction between RPG in acetonitrile with p-chloranilic acid (CAA) or 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in dioxane and subsequent formation of intensely colored radical anions of the reagents which were measured at 520 nm (CAA) or 590 nm (DDQ). Several experimental variables affecting the complex formation, stability of the colored species and sensitivity of the reaction were optimized. Under the optimized conditions, Beer?s law was obeyed over the concentration ranges of 20-400 and 5-80 ?g ml-1 RPG for CAA and DDQ methods, respectively, and the corresponding correlation coefficients were 0.9995 and 0.9998. The apparent molar absorptivity values were 1.02x103 and 4.60x103 for CAA and DDQ methods respectively, with corresponding Sandell sensitivity values of 0.4438 and 0.0984 ?g cm-2. Limits of detection (LOD) were calculated to be 7.07 and 2.42 ?g ml-1 and the limits of quantification (LOQ) were 21.43 and 7.33 ?g ml-1 RPG, for CAA method and DDQ method, respectively. Validation results demonstrated that the inter day and intra day accuracy were up to 97.56%. The precision determined did not exceed 2.5% of RSD. The methods were successfully used for the determination of RPG in tablet form and the results were in good agreement with the label claims as shown by the recoveries which were in the range of 99.22- 102.8% with standard deviation values < 2%. The accuracy of the method was confirmed by recovery studies via standardaddition procedure with excellent recovery 98.24-104.0 ? 1.08-3.35.

scholarly journals CHARGE-TRANSFER COMPLEXES OF CHLORPHENOXAMINE HYDROCHLORIDE WITH CHLORANILIC ACID, 2,3-DICHLORO-5,6-DICYANO-1,4-BENZOQUINONE AND 7,7,8,8-TETRACYANOQUINODIMETHANE AS π-ACCEPTORS

2019 ◽  
pp. 117-123
Author(s):  
AKRAM M. EL-DIDAMONY ◽  
MOUNIR Z. SAAD ◽  
GEHAD M. RAMADAN
Keyword(s):  
Charge Transfer ◽  
Limit Of Detection ◽  
Standard Free Energy ◽  
Pharmaceutical Preparations ◽  
Molar Absorptivity ◽  
Charge Transfer Complexes ◽  
Reaction Products ◽  
Chloranilic Acid ◽  
Accuracy And Precision ◽  
Ct Complex

Objective: To develop simplified, accurate and precise visible spectrophotometric strategies for the assay of chlorphenoxamine hydrochloride (CPX) in pure drug and in its pharmaceutical preparations. Methods: The described methods depended on the formation of charge-transfer (CT) complexes of intense color between CPX as donor with three π-acceptors, chloranilic acid (CLA), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), and 7,7,8,8-tetracyanoquinodimethane (TCNQ) and the colored reaction products were estimated spectrophotometrically at 520 nm, 460 nm and 840 nm for CLA, DDQ, and TCNQ complexes, individually. All the optimum conditions were established. The proposed methods were validated in term of linearity, limit of detection as per the international conference on harmonization guidelines ICH Q2 (R1). Results: The complexes obeyed Beer’s law in the concentration range of 16-144, 6-54 and 4-76 μg/mlwith molar absorptivity at 0.30×104, 0.68×104 and 0.58×104 l/mol/cm for CLA, DDQ, and TCNQ, individually. According to Benesi-Hildebrand plots, the association constants and changes of standard free energy were determined. 1:1 was the ratio of composition of the formed CT-complex. Conclusion: The obtained results revealed that the developed method can be applied successfully for the determination of CPX in drug formulations samples with good accuracy and precision.

scholarly journals Utility of σ and π-Acceptors for the Spectrophotometric Determination of Gemifloxacin Mesylate in Pharmaceutical Formulations

2008 ◽  
Vol 5 (3) ◽  
pp. 493-498 ◽  
Author(s):  
Marothu Vamsi Krishna ◽  
Dannana Gowri Sankar
Keyword(s):  
Charge Transfer ◽  
Good Accuracy ◽  
Pharmaceutical Formulations ◽  
Charge Transfer Complexes ◽  
Complexation Reaction ◽  
Experimental Conditions ◽  
Spectrophotometric Methods ◽  
Accuracy And Precision ◽  
Charge Transfer Complexation

In this study, four simple, fast, accurate and sensitive spectrophotometric methods have been developed for the determination of gemifloxacin mesylate in pharmaceutical formulations. The methods are based on the charge transfer complexation reaction of the drug as n-electron donor with sigma (σ)-acceptor iodine, and thepi(π)-acceptors 2, 3-dichloro-5, 6-dicyano-p-benzoquinone (DDQ)-7,7,8,8-tetra cyanoquinodimethane (TCNQ) and tetracyanoethylene (TCNE). The obtained charge transfer complexes were measured at 290nm for iodine (in 1, 2-dichloro ethane), at 470, 840 and 420 nm for DDQ, TCNQ and TCNE (in acetonitrile), respectively. Optimization of different experimental conditions is described. Beer's law is obeyed in the concentration range of 6-30, 2-10, 2.5-12.5 and 1-5 μg mL−1for iodine, DDQ, TCNQ and TCNE methods, respectively. The proposed methods were applied successfully to the determination of GFX in pharmaceutical formulations with good accuracy and precision.

scholarly journals Charge Transfer Complexes of Ketotifen with 2,3-Dichloro-5,6-dicyano-p-benzoquinone and 7,7,8,8-Tetracyanoquodimethane: Spectroscopic Characterization Studies

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2039
Author(s):  
Gamal A. E. Mostafa ◽  
Ahmed Bakheit ◽  
Najla AlMasoud ◽  
Haitham AlRabiah
Keyword(s):  
Charge Transfer ◽  
Spectroscopic Characterization ◽  
Molar Ratio ◽  
Charge Transfer Complexes ◽  
Physical Parameters ◽  
Spectrophotometric Methods ◽  
Theoretical Approaches ◽  
The Stability ◽  
Ct Complexes

The reactions of ketotifen fumarate (KT) with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) as π acceptors to form charge transfer (CT) complexes were evaluated in this study. Experimental and theoretical approaches, including density function theory (DFT), were used to obtain the comprehensive, reliable, and accurate structure elucidation of the developed CT complexes. The CT complexes (KT-DDQ and KT-TCNQ) were monitored at 485 and 843 nm, respectively, and the calibration curve ranged from 10 to 100 ppm for KT-DDQ and 2.5 to 40 ppm for KT-TCNQ. The spectrophotometric methods were validated for the determination of KT, and the stability of the CT complexes was assessed by studying the corresponding spectroscopic physical parameters. The molar ratio of KT:DDQ and KT:TCNQ was estimated at 1:1 using Job’s method, which was compatible with the results obtained using the Benesi–Hildebrand equation. Using these complexes, the quantitative determination of KT in its dosage form was successful.

scholarly journals Extractive Spectrophotometric Methods for Determination of Zolmitriptan in Tablets

2007 ◽  
Vol 90 (5) ◽  
pp. 1237-1241 ◽  
Author(s):  
Zeynep Aydogmus ◽  
Ipek Inanli
Keyword(s):  
High Performance ◽  
Correlation Coefficients ◽  
Bromothymol Blue ◽  
Chromatography Method ◽  
Statistical Comparison ◽  
Spectrophotometric Methods ◽  
Accuracy And Precision ◽  
Liquid Chromatography Method ◽  
Comparison Of The Results

Abstract Two simple and sensitive extractive spectrophotometric methods have been developed for determination of zolmitriptan (ZTP) in tablets. These methods are based on the formation of yellow ion-pair complexes between ZTP and tropaeolin OO (TPOO) and bromothymol blue (BTB) in citratephosphate buffer of pH 4.0 and 6.0, respectively. The formed complexes were extracted with dichloromethane and measured at 411.5 and 410 nm for TPOO and BTB, respectively. The best conditions of the reactions were studied and optimized. Beer's law was obeyed in the concentration ranges of 220 and 1.517 g/mL with molar absorptivities of 1.42 104 and 1.60 104 L/mol/cm for the TPOO and BTB methods, respectively. Correlation coefficients were 0.9998 and 0.9999 for TPOO and BTB methods, respectively. Limits of detection of the TPOO and BTB methods were 0.341 and 0.344 g/mL, respectively, and the limits of quantitation were 1.034 and 1.051 g/mL, respectively. Sandell's sensitivity and stability constant were also calculated. The proposed methods have been applied successfully for the analysis of the drug in its dosage forms. No interference was observed from excipients present in tablets. Statistical comparison of the results with those obtained by a high-performance liquid chromatography method showed excellent agreement and indicated no significant differences in accuracy and precision.

scholarly journals Use of N, N-diethyl-p-phenylenediamine sulphate for the spectrophotometric determination of some phenolic and amine drugs

2010 ◽  
Vol 60 (2) ◽  
pp. 217-227 ◽  
Author(s):  
Padmarajaiah Nagaraja ◽  
Ashwinee Shrestha ◽  
Anantharaman Shivakumar ◽  
Avinash Gowda
Keyword(s):  
Spectrophotometric Determination ◽  
Correlation Coefficients ◽  
Dosage Forms ◽  
Pharmaceutical Dosage Forms ◽  
Variable Parameters ◽  
Spectrophotometric Methods ◽  
Linear Relationships ◽  
Colored Product ◽  
And Performance

Use ofN, N-diethyl-p-phenylenediamine sulphate for the spectrophotometric determination of some phenolic and amine drugsSpectrophotometric methods are proposed for the determination of drugs containing a phenol group [salbutamol sulphate (SLB), ritodrine hydrochloride (RTD), isoxsuprine hydrochloride (IXP)] and drugs containing an aromatic amine group [dapsone hydrochloride (DAP), sulfamethoxazole (SFM), and sulfadiazine (SFD)] in pharmaceutical dosage forms. The methods are based on coupling ofN, N-diethyl-p-phenylenediamine sulphate with the drugs in the presence of KIO4to give a green colored product (λmaxat 670 nm) and a red colored product (λmaxat 550 nm), respectively. Linear relationships with good correlation coefficients (0.9986-0.9996) were found between absorbance and the corresponding concentration of drugs in the range 1-7, 2-22, 1-17, 1.5-12, 2-25, and 2-21 μg mL-1for SLB, RTD, IXP, DAP, SFM and SFD, respectively. Variable parameters such as temperature, reaction time and concentration of the reactants have been analyzed and optimized. The RSD of intra-day and inter-day studies was in the range of 0.2-1.0 and 0.4-1.0%, respectively. No interference was observed from common pharmaceutical adjuvants. The reliability and performance of the proposed methods was validated statistically; the percentage recovery ranged from 99.5 ± 0.1 to 99.9 ± 0.3%. Limits of detection were 0.14, 0.21, 0.51, 0.44, 0.33 and 0.37 μg mL-1for SLB, RTD, IXP, DAP, SFM, and SFD, respectively.

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