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 Drug Clonazepam in Pure form and Pharmaceutical Tablets by Oxidative Coupling Reaction with Chlorpromazine hydrochloride

2019 ◽  
Vol 10 (02) ◽  
Author(s):  
Nahlah Salman Saddam ◽  
K H Kadhim
Keyword(s):  
Oxidative Coupling ◽  
Coupling Reaction ◽  
Molar Absorptivity ◽  
Pure Form ◽  
Chlorpromazine Hydrochloride ◽  
Pharmaceutical Tablets ◽  
Spectrophotometric Methods ◽  
Oxidative Coupling Reaction ◽  
Quantification Limit

Sensitive, simple and a Precise spectrophotometric methods were development for the estimation reduced clonazepam (CZP) in purity form and in the pharmaceutical tablets from through using potassium bromate as oxidizing reagent for the drug and Chlorpromazine Hydrochloride (CPZ.HCL) as new chromogenic reagent. That led to forms colored products with a maximum absorbance of 530 nm. For the conditions reaction have been studied and optimized. The linearity range for Clonazepam was 0.05–3.5 μg/ ml, while the detections limit 0.0061 and the quantification limit 0.020 μg ml-1. The Molar Absorptivity 1.381×104 L/ mol cm with Shandell's sensitivity 0.0228 μg. cm-2. Finally the proposed methods were successfully Appling for estimation CZP in pure form and commercial formulations.

scholarly journals Spectrophtometric determination of Hydrochlorothiazaide by oxidative coupling with O-Phenylendiamine

2019 ◽  
Vol 24 (2) ◽  
pp. 46
Author(s):  
Rahma Abdul Hameed Hasan1 ◽  
Ali Ibraheem Khaleel2
Keyword(s):  
Oxidative Coupling ◽  
Coupling Reaction ◽  
Molar Absorptivity ◽  
Water Soluble ◽  
Sensitivity Index ◽  
Medium Ph ◽  
Oxidative Coupling Reaction ◽  
Stable Product ◽  
Orange Color

This study includes the development of a new sensitive spectrophotometric method for the determination of a hydrochlorothaizide in aqueous solution and pharmaceultical preparations. The method is based on the oxidative coupling reaction of hydrochlorothaizide with O-phenylendiamine reagent in a acidic medium pH 1.5 in the presence of potassium ferricyanide  to produce an intense orange color, water soluble and stable product , which exhibits maximum absorption at 450 nm. Beer’s law is obeyed over the concentration arange 6 to 48 µg.ml-1 of hydrochlorothaizide, with a molar absorptivity of  3602.17  L.mo1-1 .cm -1 , Sandell’s sensitivity index of 0.03 µg.cm-2 , relative error range not more than 0.215% , and D.L 0.0835µg.ml-1 . The method has been successfully applied for the determination of hydrochlorothaizide in tablets.   http://dx.doi.org/10.25130/tjps.24.2019.030

scholarly journals Spectrophotometric Determination of Phenylephrine Hydrochloride in Pharmaceutical Preparations by Oxidative Coupling Reaction

2020 ◽  
Vol 10 (03) ◽  
pp. 323-327
Author(s):  
Ahmed Hamdi Hattab ◽  
Abdul Majeed Khorsheed Ahmed ◽  
Sunbul M. Anwar
Keyword(s):  
Oxidative Coupling ◽  
Pharmaceutical Preparations ◽  
Coupling Reaction ◽  
Molar Absorptivity ◽  
Simple Condition ◽  
First Line ◽  
Phenylephrine Hydrochloride ◽  
Oxidative Coupling Reaction ◽  
Prevention And Treatment

Phenylephrine is a medication mainly applied as a decongestant to relieve hemorrhoids, increase blood pressure, and dilate the pupil. It is the first-line choice for prevention and treatment of hypotension during spinal anesthesia for cesarean section. However, many methods were used for the determination of this drug and its properties. This paper proposes a method that uses N, N dimethyl-p-phenylenediamine dihydrochloride as a new chromogenic reagent (NNDPH). This method is based on the oxidative coupling reaction of phenylephrine with N, N dimethyl-p-phenylenediamine dihydrochloride with ferric chloride in basic media to form green-blue soluble dye product. The outcomes demonstrate that the maximum absorption is at 680 nm, molar absorptivity of 5.54 × 103 mol-1.cm-1, and Sandell’s sensitivity of 0.038 μg.cm-2. The concentration range of 4 to 22 μg.mL-1 of the product is conformable to Beer’s law. Furthermore, it is applied successfully for estimating the drug properties on a simple condition or pharmaceutical preparations.

scholarly journals Spectrophotometric method for the determination of benzocaine by cerium ammonium sulphate with promethazine hydrochloride in pure and phar-maceuticals preparation

2019 ◽  
Vol 10 (2) ◽  
pp. 1420-1423 ◽  
Author(s):  
Amal H. Mhemeed
Keyword(s):  
Ammonium Sulphate ◽  
Spectrophotometric Method ◽  
Oxidative Coupling ◽  
Pharmaceutical Preparation ◽  
Coupling Reaction ◽  
Molar Absorptivity ◽  
Oxidative Coupling Reaction ◽  
Promethazine Hydrochloride ◽  
Cerium Ammonium

Easy, the accurate, sensitive spectrophotometric method used to determine Benzocaine in a pure and pharmaceutical preparation. The proposed method depends on using Promethazine hydrochloride as a reagent. Where it depends on oxidative coupling reaction of benzocaine by cerium ammonium sulphate with promethazine hydrochloride in the presence of hydrochloric acid to form green dye product, lmax 615 nm. Beers law is obeyed in the concentration of (5 –300 µg.ml-1). The molar absorptivity is (1.77 * 10 3) L.mol -1.cm-1, a sandal sensitivity of (0.0098) µq.cm-2 and RSD (± 0.56 %). The method gave a successful determination for benzocaine in a pharmaceutical preparation.

scholarly journals Spectrophotometric Determination of sulphadiazine by oxidative coupling reaction with ortho-amino phenol as reagent

2019 ◽  
Vol 24 (4) ◽  
pp. 40
Author(s):  
Aisha A. Abd ◽  
Ali I. Khaleel ◽  
, Faiez M. Hamed
Keyword(s):  
Oxidative Coupling ◽  
Coupling Reaction ◽  
Molar Absorptivity ◽  
Dosage Forms ◽  
Pharmaceutical Dosage Forms ◽  
Oxidative Coupling Reaction ◽  
Relative Standard ◽  
Amino Phenol ◽  
532 Nm

A simple, rapid and sensitive spectrophotometric method for determination of sulphadiazine (SDZ) in aqueous solution is described. The method iis based on the oxidation of SDZ by potasium Periodate, and coupling with ortho-amino phenol to give a violet colour of  maximum absorbaance at 532 nm. Beer's law is obeyed over the concentration range of 5-40 µg /ml of SDZ with a (R2=0.9980) and molar absorptivity 5581.6 L.mol-1.cm-1  and a relative error in the range of - 0.06 - 2.3  % and a relative standard deviation of not more than 0.31 %. The composition of the resulting product is also investigated and it is found to be1:1. The method is successfully applied for the determinatiion of SDZ in pure and pharmaceutical dosage forms, with recovery of noot less than 101.1%.   http://dx.doi.org/10.25130/tjps.24.2019.070

Sign in / Sign up

Export Citation Format

Share Document