scholarly journals Use of Charge Transfer Complexation Reactions for the Spectrophotometric Determination of Sumatriptan in Pharmaceuticals

2012 ◽  
Vol 2012 ◽  
pp. 1-10
Author(s):  
Kudige N. Prashanth ◽  
Basavaiah Kanakapura ◽  
Madihalli S. Raghu ◽  
Kanakapura B. Vinay
Keyword(s):  
Charge Transfer ◽  
Correlation Coefficients ◽  
Molar Absorptivity ◽  
Spectrophotometric Methods ◽  
Ct Complex ◽  
Reaction Stoichiometry ◽  
Complexation Reactions ◽  
Charge Transfer Complexation ◽  
Job's Method

Studies were carried out to use the charge-transfer reactions of sumatriptan (SMT), extracted from neutralized sumatriptan succinate (STS), as n-electron donor with the π-acceptor, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and σ-acceptor, and iodine (I2). The formation of the colored complexes was utilized for the development of simple, rapid, and accurate spectrophotometric methods for the determination of SMT in pure form as well as in its tablets. The quantification of colored products was made spectrophotometrically at 585 nm for the CT complex formed between SMT and DDQ (DDQ method) and at 375 nm for the CT complex formed between SMT and I2 (I2 method). Beer’s law is obeyed over the concentration ranges of 4.0–56.0 μg mL−1 and 2.0–28.0 for DDQ and I2, respectively, with correlation coefficients () of 0.9997 and 0.9998. The analytical parameters such as apparent molar absorptivity, Sandell’s sensitivities, and limits of detection (LOD) and quantification (LOQ) are also reported for both methods. The described methods were successfully applied to the determination of SMT in tablets. No interference was observed from the common excipients present in tablets. The reaction stoichiometry in both methods was evaluated by Job’s method of continuous variations and was found to be 1 : 1 (donor : acceptor).

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 Spectrophotometric Methods for the Assay of Pyrilamine Maleate Using Chromogenic Reagents

2010 ◽  
Vol 7 (4) ◽  
pp. 1507-1513 ◽  
Author(s):  
V. Annapurna ◽  
G. Jyothi ◽  
V. Nagalakshmi ◽  
B. B. V. Sailaja
Keyword(s):  
Charge Transfer ◽  
Oxidative Coupling ◽  
Coupling Reaction ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Method Of Least Squares ◽  
Spectrophotometric Methods ◽  
Oxidative Coupling Reaction ◽  
Charge Transfer Complexation

Simple, accurate and reproducible UV spectrophotometric methods were established for the assay of pyrilamine maleate (PYRA) based on the formation of oxidative coupling and precipitation, charge transfer complexation products. Method A includes the oxidative coupling reaction of PYRA with 3-methyl-2-benzathiazolinone hydrazone (MBTH) in presence of Ce(IV). The formation of oxidative coupling product with 4-amino phenazone (4-AP) in presence of K3Fe(CN)6is incorporated in method B. Precipitation/charge transfer complex formation of the PYRA with tannic acid (TA)/Metol-Cr(VI) in method C were proposed. The optical characteristics such as Beers law limits, molar absorptivity and Sandell’s sensitivity for the methods (A-C) are given. Regression analysis using the method of least squares was made to evaluate the slope (b), intercept (a) and correlation coefficient (r) and standard error of estimation (Se) for each system. Determination of pyrilamine in bulk form and in pharmaceutical formulations were also incorporated.

scholarly journals Spectrophotometric Determination of Three Anti-Ulcer Drugs Through Charge-Transfer Complexation

2002 ◽  
Vol 85 (5) ◽  
pp. 1003-1008 ◽  
Author(s):  
Sheikha Al-Ghannam ◽  
Fathalla Belal
Keyword(s):  
Free Energy ◽  
Charge Transfer ◽  
Stability Constants ◽  
Pharmaceutical Preparations ◽  
Correlation Coefficients ◽  
Spectrophotometric Assay ◽  
Electron Donors ◽  
Radical Anions ◽  
Charge Transfer Complexation

Abstract A simple charge-transfer complexation method is described for the spectrophotometric assay of nizatidine, ranitidine, and famotidine. This method is based on interaction of these drugs, as n-electron donors, with 7,7,8,8-tetracyanoquinodimethane, as the π-acceptor, in acetonitrile to give highly colored green radical anions that are measured at 840 nm. Calibration graphs for the 3 compounds are linear over the concentration ranges of 1–6 μg/mL for nizatidine and ranitidine and 1–7 μg/mL for famotidine, with correlation coefficients (n = 6) of &gt;0.999. The conditioned stability constants and the free energy changes were measured; the values obtained were generally high and negative, respectively, suggesting highly stable complexes. The proposed method was successfully applied to the determination of the drugs in pharmaceutical preparations. The assay results were in accordance with those obtained by using reference methods.

scholarly journals Spectrophotometric determination of quetiapine fumarate in pharmaceuticals and human urine by two charge-transfer complexation reactions

2012 ◽  
Vol 18 (2) ◽  
pp. 263-272 ◽  
Author(s):  
K.B. Vinay ◽  
H.D. Revenasiddappa
Keyword(s):  
Charge Transfer ◽  
Human Urine ◽  
Charge Transfer Complexes ◽  
Experimental Conditions ◽  
Chloranilic Acid ◽  
Quetiapine Fumarate ◽  
Complexation Reactions ◽  
Charge Transfer Complexation ◽  
Spiked Human Urine

Two simple, rapid and accurate spectrophotometric procedures are proposed for the determination of quetiapine fumarate (QTF) in pharmaceuticals and in spiked human urine. The methods are based on charge transfer complexation reactions of free base form of the drug (quetiapine, QTP), as n-electron donor (D), with either p-chloranilic acid (p-CAA) (method A) or 2,3-dichloro-5,6-dicyanoquinone (DDQ) (method B) as ?-acceptors (A). The coloured charge transfer complexes produced exhibit absorption maxima at 520 and 540 nm, in method A and method B, respectively. The experimental conditions such as reagent concentration, reaction solvent and time have been carefully optimized to achieve the maximum sensitivity. Beer?s law is obeyed over the concentration ranges of 8.0 - 160 and 4.0 - 80.0 ?g ml-1, for method A and method B, respectively. The calculated molar absorptivity values are 1.77 ? 103 and 4.59 ? 103 l mol-1cm-1, respectively, for method A and method B. The Sandell sensitivity values, limits of detection (LOD) and quantification (LOQ) have also been reported. The stoichiometry of the reaction in both cases was accomplished adopting the limiting logarithmic method and was found to be 1: 2 (D: A). The accuracy and precision of the methods were evaluated on intra-day and inter-day basis. The proposed methods were successfully applied for the determination of QTF in pharmaceutical formulations and spiked human urine.

scholarly journals Spectrophotometric Determination of Sulfamethoxazole Based on Charge-Transfer Complexation with Sodium Nitroprusside

2017 ◽  
Vol 30 (3) ◽  
pp. 102
Author(s):  
Tariq Y. Mahmoud ◽  
Sarmad B. Dikran ◽  
Alaa K. Mohammed
Keyword(s):  
Charge Transfer ◽  
Sodium Nitroprusside ◽  
Pharmaceutical Preparation ◽  
Molar Absorptivity ◽  
Amine Hydrochloride ◽  
Colored Complex ◽  
Central Composite Experimental Design ◽  
Charge Transfer Complexation ◽  
Good Agreement

   A simple, accurate and precise spectrophotometric method has been developed for the analysis of sulfamethoxazole (SMZ) in pure form and pharmaceutical preparation. The method involves a direct charge transfer complexation of sulfamethoxazole (SMZ) with sodium nitroprusside (SNP) in alkaline medium and the presence of hydroxyl amine hydrochloride. Variables affecting the formation of the formed orange colored complex were optimized following two approaches univariate and central composite experimental design (CCD) multivariate. Under optimum recommended conditions, the formed complex exhibits λmax at 512 nm and the method conforms Beer's law for SMZ concentration in the range of 5.0-150.0 (µg.mL-1) with molar absorptivity 1.139×103 L.mol-1.cm-1, and r = 0.9997. Analysis of SMZ pharmaceutical dosages shows a good agreement with the real amounts.

scholarly journals Simple Methods for the Spectrophotometric Determination of Carvedilol

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Divya N. Shetty ◽  
B. Narayana
Keyword(s):  
Charge Transfer ◽  
Complex Formation ◽  
Confidence Level ◽  
Charge Transfer Complex ◽  
Condensation Reaction ◽  
Pharmaceutical Preparations ◽  
Molar Absorptivity ◽  
Spectrophotometric Methods ◽  
Accuracy And Precision

Two simple spectrophotometric methods are described for the determination of carvedilol (CAR). Method A is the condensation reaction of CAR with p-dimethylaminobenzaldehyde (PDAB), and the reaction mixture exhibits maximum absorbance at 601 nm. Method B is based on the charge transfer complex formation of CAR with p-chloranil; the color developed is measured at 662 nm. The calibration graphs are found to be linear over 50.00–250.00 and 20.00–100.0 μg mL−1 with molar absorptivity values of 0.92×103 and 0.257×104 L mol−1cm−1 for CAR-PDAB and CAR-p-chloranil, respectively. Statistical comparisons of the results are performed with regard to accuracy and precision using Student’s t-test and F-test at 95% confidence level. The methods are successfully employed for the determination of CAR in pharmaceutical preparations, and the results agree favorably with the reference and proposed methods.

scholarly journals Utility of Charge Transfer and Ion-Pair Complexation for Spectrophotometric Determination of Eletriptan Hydrobromide in Pure and Dosage Forms

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Ayman A. Gouda ◽  
Ragaa El Sheikh ◽  
Rham M. El-Azzazy
Keyword(s):  
Charge Transfer ◽  
Correlation Coefficients ◽  
Standard Addition ◽  
Molar Absorptivity ◽  
Dosage Forms ◽  
Ion Pair ◽  
Charge Transfer Complexes ◽  
Alizarin Red ◽  
Relative Standard

Three simple, sensitive, and accurate spectrophotometric methods have been developed for the determination of eletriptan hydrobromide (ELT) in pure and dosage forms. The first two methods are based on charge transfer complex formation between ELT and chromogenic reagents quinalizarin (Quinz) and alizarin red S (ARS) producing charge transfer complexes which showed an absorption maximum at 569 and 533 nm for Quinz and ARS, respectively. The third method is based on the formation of ion-pair complex between ELT with molybdenum(V)-thiocyanate inorganic complex in hydrochloric acid medium followed by extraction of the colored ion-pair with dichloromethane and measured at 470 nm. Different variables affecting the reactions were studied and optimized. Beer's law is obeyed in the concentration ranges 2.0–18, 1.0–8.0, and 2.0–32 μg mL−1for Quinz, ARS, and Mo(V)-thiocyanate, respectively. The molar absorptivity, Sandell sensitivity, detection, and quantification limits are also calculated. The correlation coefficients were ≥0.9994 with a relative standard deviation (R.S.D%.) of ≤0.925. The proposed methods were successfully applied for simultaneous determination of ELT in tablets with good accuracy and precision and without interferences from common additives, and the validity is assessed by applying the standard addition technique, which is compared with those obtained using the reported method.

scholarly journals Two charge-transfer complex spectrophotometric methods for the determination of sulpiride in pharmaceutical formulations

2009 ◽  
Vol 7 (4) ◽  
pp. 870-875 ◽  
Author(s):  
Sayed Zayed
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Complex ◽  
Standard Free Energy ◽  
Pharmaceutical Formulations ◽  
Association Constants ◽  
Official Method ◽  
Chloranilic Acid ◽  
Spectrophotometric Methods ◽  
Charge Transfer Complexation

AbstractTwo simple, rapid, accurate and sensitive spectrophotometric methods are described for the determination of sulpiride. They are based on charge transfer complexation between the drug as n-electron donor and p-chloranilic acid as π acceptor or iodine as σ-acceptor. These give highly coloured complexes with absorption maxima at 518 and 363, 294 nm, respectively. Beer’s law linear ranges were 13.7–341.4 and 1.7–20.5 µg mL−1 for the p-chloranilic acid and iodine methods. The methods were successfully applied to the determination of the drug in Dogmatil® Fort tablets and the results compared with the official method. The complex association constants and standard free energy changes were calculated using Benesi-Hildebrand plots.

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