Spectrophotometric and Colorimetric Determination of Pharmaceutical by Oxidative Coupling Reaction: A Review

2020 ◽  
Vol 11 (04) ◽  
Keyword(s):  
Oxidative Coupling ◽  
Coupling Reaction ◽  
Colorimetric Determination ◽  
Oxidative Coupling Reaction

scholarly journals A novel sensitive colorimetric determination of catecholamine drug in dosage form via oxidative coupling reaction with MBTH and potassium ferricyanide

2021 ◽  
Vol 5 (1) ◽  
pp. 51-58
Author(s):  
Safwan Ashour
Keyword(s):  
Oxidative Coupling ◽  
Colorimetric Method ◽  
Standard Free Energy ◽  
Coupling Reaction ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Potassium Ferricyanide ◽  
Colorimetric Determination ◽  
Oxidative Coupling Reaction

A new and direct colorimetric method has been established for the determination of catecholamine (methyldopa, MD) in both pure form and in pharmaceutical formulations. The method is based on the oxidative coupling reaction of MD with 3-methyl-2-benzothiazolinone hydrazone hydrochloride monohydrate (MBTH) and potassium ferricyanide at pH 10.4 in aqueous medium to form an orange product that has a maximum absorption at 460 nm. Beer's law plot showed good correlation in the concentration range of 1.0−56.0 µg mL-1, with detection limit of 0.31 µg mL-1. Molar absorptivity for the above method was found to be 6.56×103 L mol-1 cm-1. All the measurements were carried out at 25 ± 1.0 °C, the formation constant (logKf) value of colored species is 9.48 and the standard free energy (DG‡) is − 54.09 KJ mol-1. This method was applied successfully to determination of MD in tablets and the results were compared with the USP method. Common excipients used as additives in tablets do not interfere in the proposed method. The method is accurate, precise and highly reproducible, while being simple, cheap and less time consuming and hence can be suitably applied for routine analysis of MD in bulk and dosage forms.

scholarly journals Indirect spectrophotometric Indirect spectrophotometric determination of chlordiazepoxide in pharmaceutical formulations via oxidative coupling reaction with phenothiazine

2018 ◽  
pp. 7-14
Author(s):  
Hind Hadi ◽  
Mariam Jamal
Keyword(s):  
Oxidative Coupling ◽  
Coupling Reaction ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Dosage Forms ◽  
Calibration Plot ◽  
Pharmaceutical Dosage Forms ◽  
Oxidative Coupling Reaction ◽  
Formed Product

Abstract A sensitive, precise and reliable indirect spectrophotometric method for the determination of chlordiazepoxide (CDE) in pure and pharmaceutical dosage forms is described. The method is based on oxidative coupling reaction between amino group resulting from acidic decomposition of CDE with phenothiazine in the presence of sodium periodate to produce an intense green soluble dye that is stable and shows a maximum absorption at 602 nm. The calibration plot indicates that Beer’s law is obeyed over the concentration range of 0.1?50 µg/mL, with a molar absorptivity of 1×104 L/mol cm and correlation coefficient of 0.9994.All the conditions that affecting on the stability and sensitivity of the formed product were studied and optimized and the suggested method was effectively applied for the determination of CDE in commercial dosage forms.

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.

Spectrophotometric Determination of Chlorpromazine Hydrochloride Using 4-Nitroanilline by Oxidative Coupling Reaction

2019 ◽  
Vol 16 (1(Suppl.)) ◽  
pp. 0194
Author(s):  
Al-rashidy Et al.
Keyword(s):  
Oxidative Coupling ◽  
Analytical Data ◽  
Reaction Medium ◽  
Coupling Reaction ◽  
Suggested Method ◽  
Sensitivity Index ◽  
Chlorpromazine Hydrochloride ◽  
Oxidative Coupling Reaction ◽  
Relative Standard

A simple, rapid spectrophotometric method has been established for the determination of chlorpromazine hydrochloride (CPZ) in its pure form and in a tablet formulations. The  suggested  method  is  based  on  the  oxidative coupling  reaction  with4-nitroainlline using KIO3 in acidic solution to produce a violet colored product with maximum absorption at λ=526 nm.The  analytical data  obtained  throughout  this  study  could  be  summarid  as  follows:  1ml of 1M HCl (pH=2.2), 1 ml  of  4-nitroanilline (1x10-2M), and 1.5ml  of (1x10-2)KIO3 per 25 ml reaction medium. The order of additions, coupling reaction time, and temperature in addition to the type of solvent were studied. The Beer′s law is obeyed over the concentration range of(5–40) µg ml-1, but the detection limit and quantification limit are 0.34 besides 1.03 µg ml-1 respectively. The correlation coefficient (r) for the calibration graph was found to be 0.9980, molar absorptivity of 10. 25 × 103 L.mol -1.cm-1, and Sandell′s sensitivity index of 0.03467 µg.cm-2. The precision and accuracy of the method were tested by calculating the percentage of relative standard deviation (RSD%) (<1.831%) and the average recovery percent (99.22%) average error percent Erel%(0.558). Direct and standard addition procedures were applied to both standards and specimens of pharmaceutical and the results indicate that the suggested method was successfully applied for the determination of CPZ.

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