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 Use of the Charge Transfer Reactions for the Spectrophotometric Determination of Risperidone in Pure and in Dosage Forms

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Hemavathi Nagaraju Deepakumari ◽  
Hosakere Doddarevanna Revanasiddappa
Keyword(s):  
Charge Transfer ◽  
Pharmaceutical Preparations ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Charge Transfer Complexes ◽  
Chloranilic Acid ◽  
Colored Complex ◽  
Relative Standard ◽  
Complexation Reactions

The aim of study was to develop and validate two simple, sensitive, and extraction-free spectrophotometric methods for the estimation of risperidone in both pure and pharmaceutical preparations. They are based on the charge transfer complexation reactions between risperidone (RSP) as n-electron donor and p-chloranilic acid (p-CA) in method A and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in method B as π-acceptors. In method A, RSP reacts with p-CA in methanol to produce a bright pink-colored chromogen measured at 530 nm whereas, in method B, RSP reacts with DDQ in dichloromethane to form orange-colored complex with a maximum absorption at 460 nm. Beer's law was obeyed in the concentration range of 0–25 and 0–50 μg/mL with molar absorptivity of and L/moL/cm for RSP in methods A and B, respectively. The effects of variables such as reagents, time, and stability of the charge transfer complexes were investigated to optimize the procedures. The proposed methods have been successfully applied to the determination of RSP in pharmaceutical formulations. Results indicate that the methods are accurate, precise, and reproducible (relative standard deviation %).

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 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 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 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.

Utility of π-acceptor reagents for spectrophotometric determination of sulphonamide drugs via charge-transfer complex formation

2009 ◽  
Vol 63 (6) ◽  
Author(s):  
Faten Nour El-Dien ◽  
Gehad Mohamed ◽  
Eman Frag
Keyword(s):  
Charge Transfer ◽  
Standard Deviation ◽  
Limit Of Detection ◽  
Molar Absorptivity ◽  
Official Method ◽  
Limit Of Quantification ◽  
Experimental Conditions ◽  
Chloranilic Acid ◽  
Relative Standard

AbstractA simple, sensitive and accurate spectrophotometric method for the determination of sulphonamides (sulphamethoxazole (SMZ), sulphaguanidine (SGD), sulphaquinoxaline sodium (SQX), sulphametrole (SMR), and sulphadimidine sodium (SDD)) has been developed. The charge-transfer reactions between sulphonamides as n-electron donors and 7,7,8,8-tetracyanoquinodimethane (TCNQ), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), and 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone (chloranilic acid, p-CLA) as π-acceptors resulting in highly coloured complexes were studied. Experimental conditions for these CT reactions were carefully optimised. Beer’s law is valid over the concentration ranges from 4–280 µg mL−1, 4–260 µg mL−1, 4–200 µg mL−1, and 4–200 µg mL−1 of SMZ, SGD, SQX, and SDD using DDQ reagent, respectively. While the calibration curves are linear in the concentration ranges from 4–180 µg mL−1, 4–80 µg mL−1, 4–60 µg mL−1, 4–180 µg mL−1, and 4–60 µg mL−1 of SMZ, SGD, SQX, SMR, and SDD, respectively, using TCNQ reagent and from 4–380 µg mL−1 and 4–300 µg mL−1 of SQX and SDD, respectively, using p-CLA reagent, respectively. Different analytical parameters, namely molar absorptivity (ε), standard deviation, relative standard deviation, correlation coefficient, limit of detection, and limit of quantification, were calculated. The results obtained by the proposed methods are in good agreement with those obtained by the official method as indicated by the percent recovery values.

Spectrophotometric Determination of Zolmitriptan in Pure Form and in Tablets Through Charge Transfer Complex Reaction

2019 ◽  
Author(s):  
Safwan Ashour
Keyword(s):  
Charge Transfer ◽  
Limit Of Detection ◽  
Pharmaceutical Preparations ◽  
Dominant Mode ◽  
Pure Form ◽  
Apert Syndrome ◽  
Charge Transfer Complexes ◽  
Midfacial Hypoplasia ◽  
Limit Of Quantitation

Apert syndrome (AS) a type of acrocephalosyndactyly is a rare congenital disorder with autosomal dominant mode of transmission that consists of craniofacial synostosis, midfacial hypoplasia and bilateral limb syndactyly. Patients present in early childhood for multiple surgeries which make it imperative to know about various anaesthetic implications like difficult airway ventilation, airway hyper reactivity, associated congenital anomalies, increased airway secretions and deranged temperature thermoregulation associated with this syndrome. The patient should be thoroughly evaluated preoperatively and managed accordingly. We discuss the successful management of a three and a half years old male child two simple, rapid and selective colorimetric methods were developed for the determination of zolmitriptan (ZMT) in pure form and pharmaceutical preparations. These methods are based on the directly formation of charge-transfer complexes between ZMT and m-nitrophenol (MNP) in aqueous medium (ZMT: MNP, 1:1) and 2,4-dinitrophenol (DNP) in ethanol:water (80:20). The developed method involves formation of coloured complexes (1:1) of ZMT with MNP and DNP. The yellow formed complexes were quantitatively measured at 400 and 440 nm for ZMT-MNP and ZMT-DNP, respectively. Beer's law was obeyed in the concentration ranges of 3.0–260 μg/mL for MNP and 3.5–120 μg/mL for DNP. Limit of detection and limit of quantitation for MNP were calculated as 0.58 and 1.75 μg/mL, respectively, and for DNP were 0.32 and 0.97 μg/mL, respectively. The method was validated with respect to accuracy, robustness and selectivity. The proposed method has been successfully applied for the determination of ZMT in tablets.

scholarly journals Spectrophotometric Determination of Zidovudine in Pharmaceuticals Based on Charge-Transfer Complexation Involving N-Bromosuccinimide, Metol and Sulphanilic Acid as Reagents

2007 ◽  
Vol 4 (2) ◽  
pp. 173-179 ◽  
Author(s):  
K. Basavaiah ◽  
U. R. Anil Kumar
Keyword(s):  
Limit Of Detection ◽  
Pharmaceutical Preparations ◽  
Reference Method ◽  
Standard Addition ◽  
Molar Absorptivity ◽  
Sulphanilic Acid ◽  
Bulk Drug ◽  
Student’S T ◽  
Charge Transfer Complexation

A simple spectrophotometric method is proposed for the determination of zidovudine(ZDV) in bulk drug and in pharmaceutical preparations. The method is based on the oxidation of ZDV by a known excess of oxidant N-bromosuccinimide (NBS), in buffer medium of pH 1.5, followed by the estimation of unreacted amount of oxidant with metol and sulphanilic acid. The reacted oxidant corresponds to the amount ZDV. The purple-red reaction product absorbs maximally at 530 nm and Beer’s law is obeyed over a range 5 to 75 μg mL-1. The apparent molar absorptivity is calculated to be 5.1×103L mol-1cm-1, and the corresponding Sandell sensitivity value is 0.052 μg cm-2. The limit of detection and quantification are found to be 0.90 and 2.72, respectively. Intra-day and inter-day precision and accuracy of the developed methods were evaluated as per the current ICH guidelines. The method was successfully applied to the assay of ZDV in tablet/capsule preparations and the results were statistically compared with those of the reference method by applying the Student’s t-test and F-test. No interference was observed from the common tablet/capsule excipients. The accuracy of the method was further ascertained by performing recovery studies via standard-addition method.

Molecular Complexes of Cyclophanes, Part XVII Charge-Transfer Complexes of [2.2]- and [2.2.2]Paracyclophane-carbamates with π-Acceptors

1987 ◽  
Vol 42 (9) ◽  
pp. 1147-1152 ◽  
Author(s):  
Aboul-fetouh E. Mourad ◽  
Verena Lehne
Keyword(s):  
Charge Transfer ◽  
Functional Group ◽  
Lone Pair ◽  
Molecular Complexes ◽  
Charge Transfer Complexes ◽  
Electronic Interactions ◽  
H Nmr ◽  
Ct Complex ◽  
Nitrogen Lone Pair ◽  
Lone Pair Electrons

Charge-transfer (CT) complexation between some [2.2]- and [2.2.2]paracyclophane-carbamates as donors with 2,3-dichloro-5.6-dicyanobenzoquinone (DDO ) as well as tetracyanoethylene (TCNE) as π-acceptors has been evidenced by VIS. 1H NMR and IR spectroscopy. The site of interaction in the two different donor systems was determined. The results reveal no contribution of the nitrogen lone pair electrons of the carbamate functional group in the CT complexation. and the interaction is mainly of π-π* type. In addition, the existence of the transannular electronic interactions in [2.2]paracyclophane derivatives is responsible for CT complex formation.

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